CAUTION - This text file is provided for the sole purpose of allowing text-string searching. It is NOT a faithful reproduction of the published document: figures, equations, special characters, and character attributes used to convey information are not reproduced in this text file; tables, which may be reproduced as text, may have lost crucial row or column alignment. A Portable Document Format (PDF) version of this document is available in the main document listing. The PDF file contains all elements of the document as published by the CCSDS. The PDF file should be used in all cases where there is a need for faithful reproduction of the information contained in the published document. CONSULTATIVE COMMITTEE FOR SPACE DATA SYSTEMS RECOMMENDATIONS FOR SPACE DATA SYSTEM STANDARDS RADIO FREQUENCY AND MODULATION SYSTEMS PART 1 EARTH STATIONS AND SPACECRAFT CCSDS 401.0-B BLUE BOOK [IMAGE] AUTHORITY Issue:: Blue Book, Issue 1 & 2 Recs. First September 1989 Release: Latest November 1994 Revision: Revision Management Council Meeting: Meeting NASA, Greenbelt, Location: Maryland USA This document has been approved for publication by the Management Council of the Consultative Committee for Space Data Systems (CCSDS) and represents the consensus technical agreement of the participating CCSDS Member Agencies. The procedure for review and authorization of CCSDS Recommendations is detailed in Reference [1] and the record of Agency participation in the authorization of this document can be obtained from the CCSDS Secretariat at the address below. This document is published and maintained by: CCSDS Secretariat Program Integration Division National Aeronautics and Space Administration Washington, DC 20546, USA CCSDS 401 B i November 1994 STATEMENT OF INTENT The Consultative Committee for Space Data Systems (CCSDS) is an organization officially established by the management of member space Agencies. The Committee meets periodically to address data systems problems that are common to all participants, and to formulate sound technical solutions to these problems. Inasmuch as participation in the CCSDS is completely voluntary, the results of Committee actions are termed Recommendations and are not considered binding on any Agency. These Recommendations are issued by, and represent the consensus of, the CCSDS Plenary body. Agency endorsement of these Recommendations are entirely voluntary. Endorsement, however, indicates the following understandings: o Whenever an Agency establishes a CCSDS-related standard, this standard will be in accord with the relevant Recommendation. Establishing such a standard does not preclude other provisions which an Agency may develop. o Whenever an Agency establishes a CCSDS-related standard, the Agency will provide other CCSDS member Agencies with the following information: -- The standard itself. -- The anticipated date of initial operational capability. -- The anticipated duration of operational service. o Specific service arrangements shall be made via memoranda of agreement. Neither these Recommendations nor any ensuing standards are a substitute for a memorandum of agreement. No later than five years from its date of issuance, these Recommendations will be reviewed by the CCSDS to determine whether they should: (1) remain in effect without change; (2) be changed to reflect the impact of new technologies, new requirements, or new directions; or (3) be retired or canceled. In those instances when a new version of a Recommendation is issued, existing CCSDS-related Agency standards and implementations are not negated or deemed to be non-CCSDS compatible. It is the responsibility of each Agency to determine when such standards or implementations are to be modified. Each Agency is, however, strongly encouraged to direct planning for its new standards and implementations towards the later version of the Recommendation. CCSDS 401 B ii November 1994 FOREWORD This document, which is a set of technical Recommendations prepared by the Consultative Committee for Space Data Systems (CCSDS), is intended for use by participating space Agencies in their development of Radio Frequency and Modulation systems for earth stations and spacecraft. These Recommendations allow implementing organizations within each Agency to proceed coherently with the development of compatible Standards for the flight and ground systems that are within their cognizance. Agency Standards derived from these Recommendations may implement only a subset of the optional features allowed by the Recommendations herein, or may incorporate features not addressed by the Recommendations. In order to establish a common framework within which the Agencies may develop standardized communications services, the CCSDS advocates adoption of a layered systems architecture. These Recommendations pertain to the physical layer of the data system. Within the physical layer, there are additional layers covering the technical characteristics, policy constraints, and procedural elements relating to communications services provided by radio frequency and modulation systems. Recommendations contained in this document have been grouped into separate sections representing technical, policy, and procedural matters. These Recommendations for Radio Frequency and Modulation Systems, Part 1: Earth Stations and Spacecraft, were developed for conventional near- earth and deep-space missions having moderate communications requirements. Part 2 will be concerned with data relay satellites and will address the needs of users requiring services not provided by the earth stations covered in this document. The CCSDS will continue to develop Recommendations for Part 1: Earth Stations and Spacecraft, to ensure that new technology and the present operating environment are reflected. New Recommendations for Part 1, which are developed in the future, will utilize the same format and be designed to be inserted into this book. Holders of this document should make periodic inquiry of the CCSDS Secretariat, at the address on page i, to make sure that their book is fully current. Through the process of normal evolution, it is expected that expansion, deletion, or modification to individual Recommendations in this document may occur. This document is therefore subject to CCSDS document management and change control procedures which are defined in reference [1]. CCSDS 401 B iii November 1994 DOCUMENT CONTROL DOCUMENT TITLE DATE STATUS/REMARKS CCSDS 401.0 B- Recommendations for January Original Issue 1 Space Data System 1987 Standards. Radio Frequency and Modulation Systems, Part 1: Earth Stations and Spacecraft, Issue- 1. CCSDS 401.0 B- Recommendations for Septemb New RF and Mod. 1 Space Data System er Recommendations Standards. Radio 1989 added to Book Frequency and at September Modulation Systems, 1989 Ottawa Part 1: Earth Stations Plenary. and Spacecraft, Issue- 1. CCSDS 401 B-1 Recommendations for June 1 New RF and Mod. and B-2 Space Data System 993 Recommendations Standards, Radio added to book Frequency and at May 1992 and Modulation Systems, June 1993 Part 1: Earth Stations Meetings. See and Spacecraft. dates in Table of Contents. CCSDS 401 B-1 Novemb Recommendations for er New RF and Mod. Space 1994 Recommendations Data System Standards, 2.6.7B, 2.6.8B, Radio 3.1.4A, and Frequency and 3.3.4. Modulation Systems, Part 1: Earth Stations and Spacecraft. CCSDS 401 B iv November 1994 REFERENCES [1] Procedures Manual for the Consultative Committee for Space Data Systems, CCSDS A00.0-Y-6, Yellow Book. Issue 6. Washington D.C.: CCSDS May 1994 or later issue. [2] Radio Frequency and Modulation Report, CCSDS 411.0 G-1, June 1990 or latest edition. [3] Radio Regulations, International Telecommunication Union, Geneva, Switzerland, 1992. [4] Recommendations and Reports of the CCIR, 1986 Plenary Assembly, Dubrovnik, Yugoslavia, 1986. [5] Radio Frequency and Modulation Systems, Spacecraft - Earth Station Compatibility Test Procedures, CCSDS 412.0 G-1, May 1992. The latest issues of CCSDS documents may be obtained from the CCSDS Secretariat at the address indicated on page i. CCSDS 401 B v November 1994 CONTENTS SECTION TITLE ISSUE PAGE NO. DATE NO. AUTHORITY 11-94 i STATEMENT OF INTENT 06-93 ii FOREWORD 06-93 iii DOCUMENT CONTROL 11-94 iv REFERENCES 06-93 v 1.0 INTRODUCTION 06-93 1.0-1 1.1 PURPOSE06-93 1.0-1 1.2 SCOPE 06-93 1.0-1 1.3 APPLICABILITY06-93 1.0-1 1.4 DOCUMENT FORMAT 06-93 1.0-1 1.5 DEEP SPACE AND NON DEEP SPACE 06-93 1.0-3 2.0 TECHNICAL RECOMMENDATIONS 06-93 2.0-1 EARTH-TO-SPACE RF RECOMMENDATION SUMMARY 06-93 2.0-2 TELECOMMAND RECOMMENDATION SUMMARY 06-93 2.0-3 SPACE-TO-EARTH RF RECOMMENDATION SUMMARY 06-93 2.0-4 TELEMETRY RECOMMENDATION SUMMARY 06-93 2.0-5 RADIO METRIC RECOMMENDATION SUMMARY 06-93 2.0-6 SPACECRAFT RECOMMENDATION SUMMARY 06-93 2.0-7 2.1 EARTH-TO-SPACE RF RECOMMENDATIONS 2.1.1 RF CARRIER MODULATION OF THE EARTH-TO-SPACE LINK 01-872.1.1-1 2.1.2 POLARIZATION OF EARTH-TO-SPACE LINKS 01-872.1.2-1 CCSDS 401 B vii November 1994 SECTION TITLE ISSUE PAGE NO. DATE NO. 2.1 EARTH-TO-SPACE RF RECOMMENDATIONS (Continued) 2.1.3A TRANSMITTER FREQUENCY SWEEP RANGE ON EARTH-TO-SPACE LINK, CATEGORY A 01-872.1.3A-1 2.1.3B TRANSMITTER FREQUENCY SWEEP RANGE ON EARTH-TO-SPACE LINK, CATEGORY B 01-872.1.3B-1 2.1.4A TRANSMITTER FREQUENCY SWEEP RATE ON EARTH-TO-SPACE LINK, CATEGORY A 01-87 2.1.4A 2.1.4.B TRANSMITTER FREQUENCY SWEEP RATE ON EARTH-TO-SPACE LINK, CATEGORY B 01-87 2.1.4B 2.1.5 RELATIONSHIP OF MODULATOR INPUT VOLTAGE TO RESULTANT RF CARRIER PHASE SHIFT 01-872.1.5-1 2.1.6 RF CARRIER SUPPRESSION ON EARTH-TO-SPACE LINKS FOR RESIDUAL CARRIER SYSTEMS 01-872.1.6-1 2.1.7B OPERATIONAL AND EQUIPMENT CONSTRAINTS RESULTING FROM SIMULTANEOUS TELECOMMAND AND RANGING IN RESIDUAL CARRIER SYSTEMS, CATEGORY B 09-892.1.7B-1 2.1.8A MINIMUM EARTH STATION TRANSMITTER FREQUENCY RESOLUTION FOR SPACECRAFT RECEIVER ACQUISITION, CATEGORY A 09-892.1.8A-1 2.1.8B MINIMUM EARTH STATION TRANSMITTER FREQUENCY RESOLUTION FOR SPACECRAFT RECEIVER ACQUISITION, CATEGORY B 09-892.1.8B-1 2.2 TELECOMMAND RECOMMENDATIONS 2.2.2 SUBCARRIERS IN TELECOMMAND SYSTEMS 01-872.2.2-1 2.2.3 CHOICE OF WAVEFORMS IN TELECOMMAND LINKS 01-872.2.3-1 2.2.4 RANGE OF TELECOMMAND BIT RATES 01-872.2.4-1 2.2.5 TELECOMMAND SUBCARRIER FREQUENCY STABILITY 01-872.2.5-1 2.2.6 SYMMETRY OF BASEBAND MODULATING WAVEFORMS 09-892.2.6-1 CCSDS 401 B viii November 1994 SECTION TITLE ISSUE PAGE NO. DATE NO. 2.3 SPACE-TO-EARTH RF RECOMMENDATIONS 2.3.1 RESIDUAL CARRIERS FOR LOW RATE TELEMETRY, SPACE-TO-EARTH LINKS 01-872.3.1-1 2.3.2 SUPPRESSED CARRIERS FOR HIGH RATE TELEMETRY, SPACE-TO-EARTH LINKS 01-872.3.2-1 2.3.3A EARTH STATION RECEIVER ACQUISITION FREQUENCY SWEEP RANGE, CATEGORY A 01-872.3.3A-1 2.3.3B EARTH STATION RECEIVER ACQUISITION FREQUENCY SWEEP RANGE, CATEGORY B 01-872.3.3B-1 2.3.4A EARTH STATION RECEIVER ACQUISITION FREQUENCY SWEEP RATE, CATEGORY A 09-892.3.4A-1 2.3.4B EARTH STATION RECEIVER ACQUISITION FREQUENCY SWEEP RATE, CATEGORY B 01-872.3.4B-1 2.3.5 POLARIZATION OF SPACE-TO-EARTH LINKS 01-872.3.5-1 2.3.6 RELATIONSHIP OF MODULATOR INPUT VOLTAGE TO RESULTANT RF CARRIER PHASE SHIFT 01-872.3.6-1 2.3.7 EARTH STATION OSCILLATOR REFERENCE FREQUENCY STABILITY 01-872.3.7-1 2.3.8 RF CARRIER SUPPRESSION ON SPACE-TO-EARTH LINKS FOR RESIDUAL CARRIER SYSTEMS 06-932.3.8-1 2.4 TELEMETRY RECOMMENDATIONS 2.4.2 MODULATING PCM WAVEFORMS FOR SUPPRESSED CARRIER SYSTEMS 01-872.4.2-1 2.4.3 SUBCARRIERS IN LOW BIT RATE RESIDUAL CARRIER TELEMETRY SYSTEMS 01-872.4.3-1 2.4.4 PSK MODULATION FOR TELEMETRY SUBCARRIERS 01-872.4.4-1 2.4.5 TELEMETRY SUBCARRIER WAVEFORMS 01-872.4.5-1 2.4.6 TELEMETRY SUBCARRIER FREQUENCY STABILITY 01-872.4.6-1 2.4.7 CHOICE OF PCM WAVEFORMS IN RESIDUAL CARRIER TELEMETRY SYSTEMS 01-872.4.7-1 CCSDS 401 B ix November 1994 SECTION TITLE ISSUE PAGE NO. DATE NO. 2.4 TELEMETRY RECOMMENDATIONS (Continued) 2.4.8 SYMMETRY OF BASEBAND MODULATING WAVEFORMS 09-902.4.8-1 2.4.9 MINIMUM MODULATED SYMBOL TRANSITION DENSITY ON THE SPACE-TO-EARTH LINK 09-892.4.9-1 2.4.10 CHANNEL INPUT AND CODING CONVENTIONS FOR QPSK SYSTEMS 09-892.4.10-1 2.4.11 PHASE-AMBIGUITY RESOLUTION FOR QPSK MODULATION SYSTEMS 05-922.4.11-1 2.4.12A MAXIMUM PERMISSIBLE PHASE AND AMPLITUDE IMBALANCES FOR SUPPRESSED CARRIER (BPSK/QPSK) RF MODULATORS FOR SPACE-TO-EARTH LINKS, CATEGORY A 05-922.4.12A-1 2.4.13B MAXIMUM PERMISSIBLE PHASE AND AMPLITUDE IMBALANCES FOR SPACECRAFT SUBCARRIER MODULATORS, CATEGORY B 06-932.4.13B-1 2.5 RADIO METRIC RECOMMENDATIONS 2.5.1A MINIMUM EARTH STATION GROUP DELAY CALIBRATION ACCURACY, CATEGORY A 09-892.5.1A-1 2.5.2A MINIMUM EARTH STATION RANGING GROUP DELAY STABILITY, CATEGORY A 09-892.5.2A-1 2.5.2B MINIMUM EARTH STATION RANGING GROUP DELAY STABILITY, CATEGORY B 09-892.5.2B-1 2.5.3A MINIMUM SPACECRAFT RANGING CHANNEL GROUP DELAY STABILITY, CATEGORY A 09-892.5.3A-1 2.5.3B MINIMUM SPACECRAFT RANGING CHANNEL GROUP DELAY STABILITY, CATEGORY B 09-892.5.3B-1 2.5.4A RANGING TRANSPONDER BANDWIDTH FOR RESIDUAL CARRIER SYSTEMS, CATEGORY A 09-892.5.4A-1 2.5.4B RANGING TRANSPONDER BANDWIDTH FOR RESIDUAL CARRIER SYSTEMS, CATEGORY B 09-892.5.4B-1 2.5.5A PN CODE PHASE SHIFT STABILITY REQUIRED IN SPACECRAFT SPREAD SPECTRUM REGENERATIVE RANGING TRANSPONDERS, CATEGORY A 09-892.5.5A-1 CCSDS 401 B x November 1994 SECTION TITLE ISSUE PAGE NO. DATE NO. 2.6 SPACECRAFT RECOMMENDATIONS 2.6.1 TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 2025 - 2120 MHz AND 2200 - 2300 MHz BANDS 01-872.6.1-1 2.6.2 TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 7145 - 7235 MHz AND 8400 - 8500 MHz BANDS01-87 2.6.2- 1 2.6.3A TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 2025 - 2110 MHz AND 8450 - 8500 MHz BANDS, CATEGORY A 01-872.6.3A-1 2.6.4A TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 7190 - 7235 MHz AND 2200 - 2290 MHz BANDS, CATEGORY A 01-872.6.4A-1 2.6.5B TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 2110 - 2120 MHz AND 8400 - 8450 MHz BANDS, CATEGORY B 01-872.6.5B-1 2.6.6B TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 7145 - 7190 MHz AND 2290 - 2300 MHz BANDS, CATEGORY B 01-872.6.6B-1 2.6.7B TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 7145 - 7190 MHz AND 31.8 - 32.3 GHz BANDS, CATEGORY B 11-942.6.7B-1 2.6.8B TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 31.8 - 32.3 GHz AND 34.2 - 34.7 GHz BANDS, CATEGORY B 11-942.6.8B-1 2.6.12 SPACECRAFT TRANSPONDER IF AND AGC AMPLIFIER BANDWIDTHS FOR COHERENT OPERATION 09-892.6.12-1 3.0 POLICY RECOMMENDATIONS 06-93 3.0-1 FREQUENCY UTILIZATION RECOMMENDATION SUMMARY 06-93 3.0-2 POWER LIMITATIONS RECOMMENDATION SUMMARY 06-93 3.0-3 MODULATION METHODS RECOMMENDATION SUMMARY 06-93 3.0-4 CCSDS 401 B xi November 1994 SECTION TITLE ISSUE PAGE NO. DATE NO. 3.0 POLICY RECOMMENDATIONS (Continued) 06-93 3.0-1 OPERATIONAL PROCEDURES RECOMMENDATION SUMMARY 06-93 3.0-5 TESTING RECOMMENDATION SUMMARY 06-93 3.0-6 SPACECRAFT SYSTEMS RECOMMENDATION SUMMARY 06-93 3.0-7 3.1 FREQUENCY UTILIZATION 3.1.1 EFFICIENT UTILIZATION OF THE 2 GHz BANDS BY SATELLITE MISSIONS 01-873.1.1-1 3.1.2A USE OF THE 8450 - 8500 MHz BAND FOR SPACE RESEARCH, CATEGORY A 01-873.1.2A-1 3.1 FREQUENCY UTILIZATION (Continued) 3.1.3A USE OF THE 13.25 - 15.35 GHz BANDS FOR SPACE RESEARCH, CATEGORY A 01-873.1.3A-1 3.1.4A CONSTRAINTS ON THE USE OF THE 14.00 - 15.35 GHz AND THE 16.6 - 17.1 GHz BANDS FOR SPACE RESEARCH, CATEGORY A 11-943.1.4A-1 3.1.5B USE OF THE 31.8 - 34.7 GHz BANDS FOR SPACE RESEARCH, CATEGORY B 01-873.1.5B-1 3.1.6B CHANNEL FREQUENCY PLAN FOR 2, 7, AND 8 GHz, CATEGORY B 01-873.1.6B-1 3.2 POWER LIMITATIONS 3.2.1 LIMITATIONS ON EARTH-TO-SPACE LINK POWER LEVELS 01-873.2.1-1 CCSDS 401 B xii November 1994 SECTION TITLE ISSUE PAGE NO. DATE NO. 3.3 MODULATION METHODS 3.3.1 OPTIMAL RANGING MODULATION WAVEFORMS FOR SIMULTANEOUS RANGING, TELECOMMANDING AND TELEMETRY OPERATIONS 09-893.3.1-1 3.3.2A CRITERIA FOR USE OF DIRECT SEQUENCE SPREAD SPECTRUM MODULATION, CATEGORY A 09-893.3.2A-1 3.3.3A CRITERIA FOR USE OF QPSK MODULATION IN SUPPRESSED CARRIER SYSTEMS, CATEGORY A 09-893.3.3A-1 3.3.4 USE OF SUBCARRIERS ON SPACECRAFT TELEMETRY CHANNELS 11-943.3.4-1 3.4 OPERATIONAL PROCEDURES 3.4.1 SIMULTANEOUS TELECOMMAND, TELEMETRY, AND RANGING OPERATIONS 09-893.4.1-1 3.4.2 CHARGED PARTICLE MEASUREMENTS IN THE TELECOMMUNICATIONS PROPAGATION PATH 09-893.4.2-1 3.4.3A OPTIMAL CHARGED PARTICLE CALIBRATION TECHNIQUES FOR RANGING DATA UNDER VARIOUS PROPAGATION CONDITIONS, SINGLE STATION TRACKING, CATEGORY A 05-923.4.3A-1 3.5 TESTING RECOMMENDATIONS 3.5.1 MINIMUM SET OF SPACECRAFT - EARTH STATION TESTS REQUIRED TO ENSURE COMPATIBILITY 09-893.5.1-1 3.6 SPACECRAFT SYSTEMS 3.6.1A REDUCTION IN INTERFERENCE FROM SPACE-TO- SPACE LINKS TO OTHER SPACE SERVICES IN THE 2025 - 2110 AND 2200 - 2290 MHz BANDS, CATEGORY A09-89 3.6.1A-1 CCSDS 401 B xiii November 1994 SECTION TITLE ISSUE PAGE NO. DATE NO. 4.0 PROCEDURAL RECOMMENDATIONS 06-93 4.0-1 DESIGN TOOLS RECOMMENDATION SUMMARY 06-93 4.0-2 COMPUTATIONAL ALGORITHMS RECOMMENDATION SUMMARY 06-93 4.0-3 4.1 DESIGN TOOLS 4.1.1 SELECTION OF OPTIMUM MODULATION INDICES FOR SIMULTANEOUS RANGING, TELECOMMAND, AND TELEMETRY OPERATIONS 09-894.1.1-1 4.1.2 TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE 09-894.1.2-1 4.1.3 STANDARD TERMINOLOGY FOR TELECOMMUNICATIONS LINK PERFORMANCE CALCULATIONS 09-894.1.3-1 4.1 DESIGN TOOLS (Continued) 4.1.4 DEFAULT PROBABILITY DENSITY FUNCTIONS FOR LINK COMPUTATION IN THE CCSDS TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE 09-914.1.4-1 4.1.5 COMPUTATIONAL TECHNIQUE FOR THE MEAN AND VARIANCE OF THE MODULATION LOSSES FOUND IN THE CCSDS TELECOMMUNICATION LINK DESIGN CONTROL TABLE 06-934.1.5-1 4.2 COMPUTATIONAL ALGORITHMS 4.2.1 COMPUTATIONAL METHOD FOR DETERMINING THE OCCUPIED BANDWIDTH OF UNFILTERED PCM/PM SIGNALS 06-93 4.2.1 5.0 TERMINOLOGY AND GLOSSARY 09-89 5.0-1 5.1 TERMINOLOGY09-89 5.1-1 5.2 GLOSSARY09-895.2-1 CCSDS 401 B xiv November 1994 1.0 INTRODUCTION 1.1 PURPOSE This document recommends standards for radio frequency and modulation systems operated by the Consultative Committee for Space Data Systems (CCSDS) member and observer agencies. 1.2 SCOPE Recommendations contained in this document, Radio Frequency and Modulation Systems, Part 1, focus upon the standardization of RF and modulation systems for earth stations and spacecraft. Part 2, when completed, will comprise Recommendations relating to data relay satellite systems. Unlike the CCSDS Radio Frequency and Modulation Report, Reference [2], these Recommendations describe the capabilities, policies, and procedures that the CCSDS agencies believe will be needed in future years. By proposing specific characteristics and attributes for subjects in these categories, the CCSDS hopes that the ensuing designs will be sufficiently similar so as to permit cross support of one agency's spacecraft by another agency's network. These Recommendations are complementary to the information contained in the RF and Modulation Report. To obtain a complete understanding of an agency's tracking facilities, readers should consult both documents. The Report describes the RF and modulation characteristics of spacecraft tracking systems that the CCSDS member and observer agencies are planning for the mid-1990 time period. It comprises a multiplicity of tables summarizing the technical characteristics of those systems. These Recommendations do not provide specific designs. Rather they describe certain capabilities and provide technical characteristics in sufficient detail so that an agency may design compatible equipment. Guidelines are also provided for the use of agencies' RF and modulation systems, as well as their use of the RF spectrum. Because an ability to provide cross support implies some standardization of design and operations, certain procedural Recommendations have been included to assist in these areas. Recommendations are assigned to one of three sections depending upon whether their primary focus is technical, policy, or procedural in nature. These Recommendations are intended to promote an orderly transition to RF and modulation systems that are internationally compatible. The CCSDS believes that this course will not only assure better engineering practices but, also, that it will facilitate international cross support agreements. 1.3 APPLICABILITY These Recommendations apply to future implementation of RF and modulation systems. In combination with the RF and Modulation Report, Reference [2], this document describes the physical transport system used to carry data to and from spacecraft and earth stations. 1.4 DOCUMENT FORMAT These introductory remarks are followed by three sections containing technical, policy, and procedural Recommendations, respectively. Often, it is not obvious to which section a Recommendation belongs because it may be concerned with more than one area. The decision usually turns upon whether the primary focus is quantitative, directive, or instructive. CCSDS 401 B Page 1.0-1 June 1993 Section 2 contains Technical Recommendations. Following the format established in the CCSDS RF and Modulation Report, technical Recommendations are subdivided into groups representing the various subsystems. These are: 2.1 Earth-to-Space Radio Frequency 2.4 Telemetry 2.2 Telecommand 2.5 Radio Metric 2.3 Space-to-Earth Radio Frequency 2.6 Spacecraft Recommendations pertaining to each of these subjects are grouped together for easy accessibility. This approach facilitates cross referencing with the Report. If a reader wishes to determine whether an agency follows a specific CCSDS Recommendation, he need only turn to the corresponding section in the Report to determine that agency's capabilities. Section 3 comprises Policy Recommendations. Because of the requirement for sharing the radio frequency spectrum, it is desirable to establish guidelines to promote its efficient use. Accordingly, these Recommendations are directive in nature and are principally concerned with operational aspects. Specific sections are: 3.1 Frequency Utilization 3.4 Operational Procedures 3.2 Power Limitations 3.5 Testing Recommendations 3.3 Modulation Methods 3.6 Spacecraft Systems Section 4 holds Procedural Recommendations. Here will be found Recommendations intended to assist agencies with procedures or processes. At this juncture, only two subsections have been identified. These are: 4.1 Design Tools 4.2 Computational Algorithms As additional procedural topics are identified, this section will be expanded with appropriate subsections. Section 5 defines Terms and provides a Glossary for acronyms used in these Recommendations. This section is intended as an aid for readers to facilitate a uniform interpretation of the Recommendations. Two subsections are required: 5.1 Terminology 5.2 Glossary Because the Recommendations are designed to be easily removable from this book to facilitate copying, a unique page numbering system has been employed. Recommendation page numbers contain information about the section, subsection, position, mission category, and page number. Thus, Page 2.5.3A-1 tells the reader, in order, that this is: a Technical Recommendation (2), for Radio Metric systems (5), the third in that subsection (3), concerned with Category A missions (A), the first page of that Recommendation (1). This numbering system is intended to avoid confusion and errors when returning pages to the book by uniquely describing the position of each page in the document. Unlike other CCSDS Recommendations which focus upon specific topics such as channel coding or SFDUs, this document contains several subjects related to radio frequency and modulation systems. To promote brevity, clarity, and expandability, the authors have adopted a Recommendation format which is similar to the one used by the International Telecommunications Union's (ITU) International Radio Consultative Committee (CCIR). CCSDS 401 B Page 1.0-2 June 1993 Each Recommendation consists of brief statements and generally requires only one or two pages. Reasons justifying each Recommendation are set forth in clear, crisp sentences. When appropriate, additional information providing the rationale for a Recommendation is included as an annex to this document. This modular format permits inclusion of additional Recommendations as the CCSDS agencies' RF and modulation systems grow and as technology matures. 1.5 DEEP SPACE AND NON-DEEP SPACE Much of the radio frequency standardization has already been accomplished by the International Telecommunications Union (ITU) and will be found in the Radio Regulations. The provisions contained in the ITU Radio Regulations, as well as applicable CCIR documents, are adopted and incorporated here by reference. Four radiocommunication services are of interest to the CCSDS. In accordance with the ITU definitions, these are the Space Research Service, the Space Operation Service, the Earth Exploration Satellite Service, and the Meteorological Satellite Service. Within the Space Research Service, a distinction is made between Deep Space and non-Deep Space spacecraft. Those bands allocated to Space Research/Deep Space shall only be used by spacecraft engaged in interplanetary research, whose range exceeds a specified distance. Earth station-spacecraft distance is important for two reasons. First, certain frequencies are reserved for spacecraft operating in Deep Space. Second, the RF and modulation characteristics may be different for the two categories. Formerly, the Radio Regulations set the Deep Space boundary at lunar distance. However, the advent of spacecraft in highly elliptical earth orbits that go beyond lunar distance, or which may be in orbits around the sun-earth libration points, resulted in non-optimum use of the Deep Space bands when frequency assignments for these missions were based upon the former definition. In October 1988, the World Administrative Radio Conference (WARC) ORB-88 revised the boundary for Deep Space contained in Article 1 of the ITU Radio Regulations. The new boundary for Deep Space, which became effective on 16 March 1990, has been established to be at a distance equal to, or greater than, 2.0 x 10 6 km. While the Radio Regulations contain a definition for Deep Space, they do not specifically name that zone lying closer to the earth. Thus, there is no internationally recognized term for non-Deep Space missions. Several years ago, the CCSDS recognized the deficiencies with the ITU's lunar distance Deep Space boundary. Accordingly, CCSDS members agreed among themselves to establish the Deep Space boundary at 2.0 x 10 6 km whenever that was possible under the then existing Radio Regulations. To avoid confusion with the ITU's definition for Deep Space, as well as to simplify the nomenclature for missions at any distance, the CCSDS defined the following mission categories: Category A Those missions having an altitude above the earth of less than, 2.0 x 10 6 km. Category B Those missions having an altitude above the earth of greater than, or equal to, 2.0 x 10 6 km. CCSDS 401 B Page 1.0-3 June 1993 Figure 1.5-1 pictorially depicts the Category A and B mission regions. Because this terminology has become well established over the years, and because the ITU has still failed to define that region lying closer to earth than 2.0 x 10 6 km, the CCSDS will continue to use the two Categories to represent the applicability of a Recommendation to a specific class of mission. Therefore, the letter A or B following the Recommendation number means that the Recommendation applies solely to Category A or Category B missions, respectively. If the Recommendation number stands alone, with neither an A or B following, then that Recommendation applies equally to both Category A and Category B missions. [IMAGE] 6445-796ab FIGURE 1.5-1: MISSION CATEGORIES CCSDS 401 B Page 1.0-4 June 1993 2.0 TECHNICAL RECOMMENDATIONS Section 2 focuses upon the technical characteristics of RF and modulation systems for earth stations and spacecraft. Each recommended standard delineates a specific capability which the CCSDS agencies believe will be needed in future years. Some suggested standards argue for retaining existing facilities, while others propose developing systems not presently used by any agency. The goal is to set forth recommended standards with which the agencies can create a group of uniform capabilities. To facilitate the document's use, this section has been subdivided into six modules, each containing an individual subject: 2.1 Earth-to-Space Radio Frequency 2.4 Telemetry 2.2 Telecommand 2.5 Radio Metric 2.3 Space-to-Earth Radio Frequency 2.6 Spacecraft Note that these subsections are identical to, and have been arranged in the same order as, those found in the CCSDS Radio Frequency and Modulation Report. However, an additional subsection for spacecraft has been included. Here, one can find those characteristics pertaining to spacecraft radio frequency and modulation systems. Six summary tables corresponding to the six modules follow these introductory remarks. These tables contain the subject matter of each recommendation, its number, and a summary description. Using these tables, the reader can quickly locate specific recommendations contained in Section 2. CCSDS 401 B Page 2.0-1 June 1993 EARTH-TO-SPACE RF RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 2.1.1 Phase Modulation Use with residual carriers. 2.1.2 Circular Polarization Use on earth-to-space RF links. 2.1.3 ñ (1-150) kHz; ñ (1- Min Cat A acquisition sweep range at A 500) kHz 2 and 7 GHz. 2.1.3 ñ (1-300) kHz; ñ (1- Min Cat B acquisition sweep range at B 1000) kHz 2 and 7 GHz. 2.1.4 500 Hz/s [...] 50 Min Cat A acquisition sweep rate A kHz/s range. 2.1.4 1 Hz/s [...] 10 kHz/s Min Cat B acquisition sweep rate B range. 2.1.5 Pos Voltage [...] Pos Modulator input voltage to carrier Phase Shift phase shift. 2.1.6 10 dB Carrier Max carrier suppression resulting Suppression from all signals. 2.1.7 Mod Indices; Data Constraints from simultaneous B Rates Codes service operations. 2.1.8 Uplink Freq Steps Min Cat A earth station transmitter A [...] 100 Hz freq resolution. 2.1.8 Uplink Freq Steps Min Cat B earth station transmitter B 0.01 [...] 5 Hz freq resolution. CCSDS 401 (2.0) B Page 2.0-2 November 1994 TELECOMMAND RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 2.2.1 Reserved 2.2.2 8 or 16 kHz, PSK, Subcarrier frequencies, modulation, Sine Wave and waveform. 2.2.3 NRZ-L, M Choice of telecommand data waveforms. 2.2.4 4000/2n; n = 0, 1, Range of telecommand bit rates. 2 ... 9 2.2.5 ñ 2x10-4fsc; ñ 1x10- Subcarrier frequency offset and 5; ñ 5x10-5 stabilities. 2.2.6 0.98 [...] 1.02 Symmetry of baseband modulating waveforms. CCSDS 401 (2.0) B Page 2.0-3 November 1994 SPACE-TO-EARTH RF RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 2.3.1 Residual Carriers Use with low bit rate telemetry systems. 2.3.2 Suppressed Carriers Use where residual carriers exceed PFD limits. 2.3.3 ñ 150 kHz; ñ 600 kHz Min Cat A acquisition sweep range A at 2 & 8 GHz. 2.3.3 ñ 300 kHz; ñ 1 MHz Min Cat B acquisition sweep range B at 2 & 8 GHz. 2.3.4 100 Hz/s [...] 420 Min Cat A acquisition sweep rate at A kHz/s 2 & 8 GHz. 2.3.4 1 Hz/s [...] 10 Min Cat B acquisition sweep rate at B kHz/s 2 & 8 GHz. 2.3.5 RCP or LCP Polarization of space-to-earth links. 2.3.6 Pos Voltage [...] Modulator input voltage to carrier Pos Phase Shift phase shift. 2.3.7 ñ 5 x 10-13 (0.2 Min earth station reference [...] s [...] 100) frequency stability. 2.3.8 10 dB Sin; 15 dB Sq Max carrier suppression resulting from all signals. CCSDS 401 (2.0) B Page 2.0-4 November 1994 TELEMETRY RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 2.4.1 Reserved 2.4.2 NRZ-M (DNRZ) Use with suppressed carrier systems. Modulation 2.4.3 Subcarriers Use with very low rate residual carrier subsystems. 2.4.4 PSK Modulation Use with telemetry subcarriers. 2.4.5 Sine Wave; Square Cat A, Cat B subcarrier waveforms. Wave 2.4.6 ñ 1x10-4fsc; ñ 1x10-6; Subcarrier frequency offset and ñ 1x10-5 stabilities. 2.4.7 NRZ-L; SP-L Choice of PCM waveforms in resid. carrier systems. 2.4.8 0.98 1.02 Symmetry of baseband modulating waveforms. 2.4.9 64; 125/1000; Min Cat A, Cat B symbol transition 275/1000 densities. 2.4.1 00=0o; 01=90o; Channel coding conventions for QPSK 0 11=180o; 10=270o systems. 2.4.1 Phase Ambiguity in Use sync marker to resolve. 1 QPSK Sys. 2.4.1 2 Degrees; 0.2 dB Max Cat A phase & amplitude BPSK 2A mod. imbal. 2.4.1 Reserved 2B 2.4.1 2 Degrees; 0.2 dB Max Cat B phase & amplitude subcar. 3B mod. imbal. CCSDS 401 (2.0) B Page 2.0-5 November 1994 RADIO METRIC RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 2.5.1 10 ns Min Cat A group delay calibration A accuracy. 2.5.2 20 ns Min Cat A earth station group delay A stability in 12h. 2.5.2 2 ns Min Cat B earth station group delay B stability in 12h. 2.5.3 ñ 50 ns Min Cat A spacecraft group delay A stability. 2.5.3 ñ 30 ns Min Cat B spacecraft group delay B stability. 2.5.4 ñ 0.5 dB (3 kHz [...] Min Cat A ranging transponder A 110 kHz) bandwidth. 2.5.4 ñ 0.5 dB (3 kHz [...] Min Cat B ranging transponder B 1.1 MHz) bandwidth. 2.5.5 20 ns Max Cat A regen. transponder PN code A delay. CCSDS 401 (2.0) B Page 2.0-6 November 1994 SPACECRAFT RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 2.6.1 221/240 Transponder Freq ratio 2025-2120 MHz to 2200- Ratio 2300 MHz. 2.6.2 749/880 Transponder Freq ratio 7145-7235 MHz to 8400- Ratio 8500 MHz. 2.6.3 221/900 Transponder Cat A Freq ratio 2025-2110 MHz to A Ratio 8450-8500. 2.6.4 765/240 Transponder Cat A Freq ratio 7190-7235 MHz to A Ratio 2200-2290. 2.6.5 221/880 Transponder Cat B Freq ratio 2110-2120 MHz to B Ratio 8400-8450 MHz. 2.6.6 749/240 Transponder Cat B Freq ratio 7145-7190 MHz to B Ratio 2290-2300 MHz. 2.6.7 749/3344 Transponder Cat B Freq ratio 7145-7190 MHz to B Ratio 31.8-32.3 GHz. 2.6.8 3599/3344 Transponder Cat B Freq ratio 34.2-34.7 GHz to B Ratio 31.8-32.3 GHz. 2.6.9 Reserved Transponder Ratio 2.6.1 Reserved Transponder Ratio 0 2.6.1 Reserved Transponder Ratio 1 2.6.1 15 [...] 45 Hz; 1 Min Cat A; Cat B transponder AGC 2 [...] 3 Hz amplifier BW. CCSDS 401 (2.0) B Page 2.0-7 November 1994 2.1.1 RF CARRIER MODULATION OF THE EARTH-TO-SPACE LINK The CCSDS, considering (a) that most space agencies currently utilize spacecraft receivers employing phase-locked loops; (b) that conventional phase-locked loop receivers require a residual carrier to operate efficiently; (c) that phase modulation results in efficient demodulation; recommends that CCSDS agencies provide a capability to support phase modulation with a residual carrier for their earth-to-space links. CCSDS 401 (2.1.1) B-1 Page 2.1.1-1 January 1987 2.1.2 POLARIZATION OF EARTH-TO-SPACE LINKS The CCSDS, considering (a) that a linear electric field polarization on links to spacecraft, having nearly omnidirectional antenna patterns, may vary considerably with aspect angle; (b) that the aspect angle of a near-earth orbiting satellite varies greatly during a pass; (c) that for satellites having a stable linear polarization in the direction of the earth station (e.g., geostationary satellites with suitable attitude stabilization or satellites using tracking antennas) the propagation effects such as Faraday rotation may cause substantial rotation in the received polarization at lower carrier frequencies; (d) that automatic correction of rotation in the earth station's polarization adds undesirable complexity to the system; (e) that most existing earth stations are equipped for RCP and LCP polarization; recommends (1) that CCSDS agencies use circular polarization on their earth-to-space RF links for telecommand and ranging; (2) that payload service links use circular polarization in those cases where TTC is carried out in the payload service band or where on-board antennas are shared with payload functions; (3) that the earth station be designed to switch between LCP and RCP polarization without causing an interruption of the transmitted carrier exceeding 5 seconds in those cases where changes of polarization are desired. CCSDS 401 (2.1.2) B-1 Page 2.1.2-1 January 1987 2.1.3A TRANSMITTER FREQUENCY SWEEP RANGE ON EARTH-TO-SPACE LINKS, CATEGORY A The CCSDS, considering (a) that the Doppler frequency shift on the earth-to-space link, resulting from relative motion between earth stations and Category A spacecraft, can achieve values up to: ñ 80 kHz at 2 GHz ñ 300 kHz at 7 GHz; (b) that the rest frequency uncertainties in spacecraft receivers are in the order of: ñ 50 kHz at 2 GHz ñ 200 kHz at 7 GHz; (c) that the lock-in frequency range of spacecraft receivers is much smaller than the frequency deviations given in (a) and (b); (d) that the Doppler frequency shift can usually be predicted to an accuracy of better than ñ 1 kHz; (e) that most of the spacecraft receivers have a tracking range up to: ñ 150 kHz at 2 GHz ñ 500 kHz at 7 GHz; (f) that the acquisition time should be kept to a minimum; recommends that the earth station's transmitter should have a minimum sweep range capability of at least: ñ 1 kHz and a maximum sweep range capability of: ñ 150 kHz at 2 GHz ñ 500 kHz at 7 GHz. CCSDS 401 (2.1.3A) B-1 Page 2.1.3A-1 January 1987 2.1.3B TRANSMITTER FREQUENCY SWEEP RANGE ON EARTH-TO-SPACE LINKS, CATEGORY B The CCSDS, considering (a) that the Doppler frequency shift on the earth-to-space link, resulting from relative motion between earth stations and category B spacecraft, can achieve values up to: ñ 250 kHz at 2 GHz ñ 900 kHz at 7 GHz; (b) that the rest frequency uncertainties in spacecraft receivers are on the order of: ñ 1 kHz at 2 GHz ñ 4 kHz at 7 GHz; (c) that the Doppler frequency shift can usually be predicted to an accuracy of ñ 1 kHz; (d) that most of the spacecraft receivers have tracking ranges less than or equal to: ñ 300 kHz at 2 GHz ñ 1 MHz at 7 GHz; (e) that the lock-in frequency range of spacecraft receivers is much smaller than the frequency deviations given in (a) and (b) above; (f) that the effect on the radio link, resulting from variation in the columnar charged-particle content, is generally negligible; (g) that the acquisition time should be kept to a minimum; recommends that the earth station's transmitter should have a minimum sweep range capability of: ñ 1 kHz at 2 and 7 GHz and a maximum sweep range capability of at least: ñ 300 kHz at 2 GHz ñ 1 MHz at 7 GHz. CCSDS 401 (2.1.3B) B-1 Page 2.1.3B-1 January 1987 2.1.4A TRANSMITTER FREQUENCY SWEEP RATE ON EARTH-TO-SPACE LINKS, CATEGORY A The CCSDS, considering (a) that the rate of change of the Doppler frequency shift on the earth-to-space link, resulting from relative motion between earth stations and Category A spacecraft, is smaller than: 3 kHz/s at 2 GHz 10 kHz/s at 7 GHz; (b) that most of the spacecraft receivers have a phase-locked loop with a bandwidth (2 BLO) in the range 200 Hz to 800 Hz at their threshold; (c) that the maximum permissible rate of input frequency variation for most types of spacecraft receivers is between 2 kHz/s and 30 kHz/s at their threshold; (d) that the frequency sweep rate on the earth-to-space link should be chosen such that the total rate of frequency variation, resulting from both the transmitter's sweep rate and the orbital Doppler rate, does not unlock the spacecraft's phase-locked loop; (e) that the acquisition time should be kept to a minimum for each mission phase; recommends that the earth station's transmitter should have a minimum frequency sweep rate capability of: 500 Hz/s and a maximum frequency sweep rate capability of at least: 50 kHz/s. CCSDS 401 (2.1.4A) B-1 Page 2.1.4A-1 January 1987 2.1.4B TRANSMITTER FREQUENCY SWEEP RATE ON EARTH-TO-SPACE LINKS, CATEGORY B The CCSDS, considering (a) that the rate of change of the Doppler frequency shift on the earth-to-space link, resulting from relative motion between earth stations and category B spacecraft, is smaller than: 60 Hz/s at 2 GHz 200 Hz/s at 7 GHz; (b) that most of the spacecraft receivers have a phase-locked loop with a bandwidth (2 BLO) in the range 10 Hz to 100 Hz at their threshold; (c) that the maximum permissible rate of input frequency variation for this type of spacecraft receiver is between 6 Hz/s and 1 kHz/s at its threshold; (d) that the maximum permissible rate of input frequency variation for signals above the receiver's threshold can be as much as 10 kHz/s; (e) that the frequency sweep rate on the earth-to-space link should be chosen such that the total rate of frequency variation, resulting from both the transmitter's sweep rate and the orbital Doppler rate, does not unlock the spacecraft's phase-locked loop; (f) that the acquisition time should be kept to a minimum for each mission phase; recommends that the earth station's transmitter should have a minimum frequency sweep rate capability of: 1 Hz/s and a maximum frequency sweep rate capability of at least: 10 kHz/s. CCSDS 401 (2.1.4B) B-1 Page 2.1.4B-1 January 1987 2.1.5 RELATIONSHIP OF MODULATOR INPUT VOLTAGE TO RESULTANT RF CARRIER PHASE SHIFT The CCSDS, considering that a clear relationship between the modulating signal and the RF carrier's phase is desirable to avoid unnecessary ambiguity problems; recommends that a positive-going voltage at the modulator input should result in an advance of the phase of the radio frequency signal. NOTE: 1. This Recommendation is also filed as Rec. 401 (2.3.6) B-1. CCSDS 401 (2.1.5) B-1 Page 2.1.5-1 January 1987 2.1.6 RF CARRIER SUPPRESSION ON EARTH-TO-SPACE LINKS FOR RESIDUAL CARRIER SYSTEMS The CCSDS, considering that high modulation indices may make the residual carrier difficult to detect with a conventional phase-locked loop receiver; recommends that CCSDS agencies select modulation indices such that the reduction in carrier power, with respect to the total unmodulated carrier power, does not exceed 10 dB. CCSDS 401 (2.1.6) B-1 Page 2.1.6-1 January 1987 2.1.7B OPERATIONAL AND EQUIPMENT CONSTRAINTS RESULTING FROM SIMULTANEOUS TELECOMMAND AND RANGING IN RESIDUAL CARRIER SYSTEMS, CATEGORY B The CCSDS, considering (a) that coherent transmissions are generally employed for making range measurements to a Category B mission spacecraft; (b) that conventional phase locked loop receivers require a residual carrier component to operate properly; (c) that sufficient power must be reserved to the residual carrier so that the spacecraft receiver can track with an acceptable phase jitter; (d) that sufficient power must be allocated to the command data channel to obtain the required bit error rate; (e) that in two-way operation, the noise contained in the transponder's ranging channel bandwidth will be retransmitted to the earth station along with the ranging signal; (f) that sufficient power must be allocated to the ranging signal to obtain the required accuracy and probability of error; (g) that some ranging systems permit the simultaneous transmission of several tone frequencies from the earth station and that a proper choice of these frequencies will minimize the cross-modulation and interference to the telecommand signal by the ranging signal; (h) that transmission of a single, low frequency ranging tone by the earth station may result in interference in the telecommand channel on the spacecraft; recommends (1) that the telecommand modulation index shall not be less than 0.2 radians peak; (2) that the telecommand data bit rate shall not exceed 2000 b/s when simultaneous telecommand and ranging operations are required; (3) that the earth station's ranging modulation index shall not exceed 1.4 radians peak; (4) that the telecommand subcarrier's period should be an integer subdivision of the data bits' period; (5) that for those ranging systems which do not conform with "recommends" (6) below, the telecommand subcarrier's period should be a coherent multiple of the ranging tone's period; (6) that, where necessary, each and every lower frequency ranging tone be chopped (modulo-2 added) with the highest frequency ranging tone; CCSDS 401 (2.1.7B) B-1 Page 2.1.7B-1 September 1989 2.1.8A MINIMUM EARTH STATION TRANSMITTER FREQUENCY RESOLUTION FOR SPACECRAFT RECEIVER ACQUISITION, CATEGORY A The CCSDS, considering (a) that Category A spacecraft receivers typically have phase-locked loop bandwidths (2 BLO) in the range of 200 to 800 Hz at their thresholds; (b) that, for spacecraft receivers having a second order phase-locked- loop with the threshold bandwidths shown in (a), the frequency lock- in range is typically 267 to 1067 Hz; (c) that steps in earth station's transmitter frequency which exceed the spacecraft receiver's lock-in range can result in long acquisition times or complete failure of the spacecraft to acquire the signal; (d) that some margin should be included to ensure proper acquisition of the earth station's signal by the spacecraft receiver's phase- locked loop; (e) that the spacecraft's receiver may fail to acquire or remain locked to the earth station's transmitted signal if abrupt phase discontinuities in that signal occur during the acquisition of that signal; recommends (1) that the earth station transmitter's frequency be adjustable over its specified operating range in increments (step size) of 100 Hz or less; (2) that the earth station transmitter's RF phase continuity be maintained at all times during tuning operations, using frequency sweep rates that are in accordance with Recommendation 401 (2.1.4A) B-1, which will ensure that the spacecraft's receiver remains locked following acquisition. CCSDS 401 (2.1.8A) B-1 Page 2.1.8A-1 September 1989 2.1.8B MINIMUM EARTH STATION TRANSMITTER FREQUENCY RESOLUTION FOR SPACECRAFT RECEIVER ACQUISITION, CATEGORY B The CCSDS, considering (a) that Category B spacecraft receivers typically have phase-locked loop bandwidths (2 BLO) in the range of 10 to 100 Hz at their thresholds; (b) that for spacecraft receivers having a second order phase-locked- loop with the threshold bandwidths shown in (a), the frequency lock- in range is typically 13 to 133 Hz; (c) that steps in earth station's transmitter frequency which exceed the spacecraft receiver's lock-in range can result in long acquisition times or complete failure of the spacecraft to acquire the signal; (d) that some margin should be included to ensure proper acquisition of the earth station's signal by the spacecraft receiver's phase- locked loop; (e) that, with certain Category B missions, it is desirable to continuously tune the earth-to-space link's transmitter frequency to maintain its value, at the spacecraft, at a single, optimal frequency; (f) that the spacecraft's receiver may fail to acquire or remain locked to the earth station's transmitted signal if abrupt phase discontinuities in that signal occur during the acquisition of that signal; recommends (1) that the earth station's transmitter frequency be variable over its specified operating range in increments (step size) which can be adjusted from 0.01 Hz to 5 Hz; (2) that the earth station transmitter's RF phase continuity be maintained at all times during tuning operations, using frequency sweep rates that are in accordance with Recommendation 401 (2.1.4B) B-1, which will ensure that the spacecraft's receiver remains locked following acquisition. CCSDS 401 (2.1.8B) B-1 Page 2.1.8B-1 September 1989 RESERVED for RECOMMENDATION 401 (2.2.1) CCSDS 401 (2.2.1) B-1 Page 2.2.1-1 January 1987 2.2.2 SUBCARRIERS IN TELECOMMAND SYSTEMS The CCSDS, considering (a) that most space agencies presently utilize either 8 kHz or 16 kHz subcarriers for telecommand transmissions where data rates are less than or equal to 4 kb/s; (b) that modulation schemes employing subcarriers reduce the interference to the RF carrier loop resulting from data sidebands; (c) that PSK modulation is the most efficient type of digital modulation because of its bit error performance; (d) that it is important to limit the occupied bandwidth; recommends that CCSDS agencies use a sine wave subcarrier for telecommand, with a frequency of either 8 kHz or 16 kHz, which has been PSK modulated. CCSDS 401 (2.2.2) B-1 Page 2.2.2-1 January 1987 2.2.3 CHOICE OF WAVEFORMS IN TELECOMMAND LINKS The CCSDS, considering (a) that NRZ-L, -M waveforms result in efficient spectrum utilization; (b) that present telecommand bit rates are generally less than or equal to 4 kb/s; (c) that telecommand data sidebands are separated from the carrier by employing a PSK subcarrier; (d) that NRZ-L waveforms result in very good signal-to-noise performance; (e) that NRZ-M waveforms avoid ambiguity errors; recommends (1) that CCSDS agencies use NRZ-L, -M waveforms with PSK subcarriers for telecommand data; (2) that due consideration be given to the bit transition density of the telecommand modulation to ensure proper operation of the spacecraft's receiving equipment. CCSDS 401 (2.2.3) B-1 Page 2.2.3-1 January 1987 2.2.4 RANGE OF TELECOMMAND BIT RATES The CCSDS, considering (a) that many space agencies utilize PCM-PSK modulation for the telecommand links; (b) that phase coherency between the PCM signal and the subcarrier facilitates system implementation; (c) that subcarrier frequencies of either 8 kHz or 16 kHz are commonly used; (d) that many space agencies have developed, or will develop, equipment using telecommand data rates in the range 8-4000 b/s; recommends (1) that CCSDS agencies provide telecommand bit rates in the range 4000/2n b/s, where n = 0, 1, 2, ..., 9; (2) that data bit and subcarrier transitions should coincide. NOTE: 1. A 4000 b/s rate should only be used with a 16 kHz subcarrier and care should be taken to ensure that harmful interactions with other signals do not occur. CCSDS 401 (2.2.4) B-1 Page 2.2.4-1 January 1987 2.2.5 TELECOMMAND SUBCARRIER FREQUENCY STABILITY The CCSDS, considering (a) that the present use of subcarriers for modulating the earth-to-space RF links represents a mature technique for both Categories A and B missions and, therefore, is a well settled standard; (b) that modifications of this standard imply costly changes to space agencies' networks; recommends that CCSDS agencies' earth stations be designed to provide telecommand subcarriers with characteristics which are equal to or better than: Maximum Subcarrier Frequency Offset ñ (2 x 10 -4)fsc; Minimum Subcarrier Frequency Stability ñ 1 x 10 -5 (1 second); Minimum Subcarrier Frequency Stability ñ 5 x 10 -5 (24 hours). NOTE: 1. fsc = frequency of telecommand subcarrier. CCSDS 401 (2.2.5) B-1 Page 2.2.5-1 January 1987 2.2.6 SYMMETRY OF BASEBAND DATA MODULATING WAVEFORMS The CCSDS, considering (a) that the earth station's transmitter power should be used as efficiently as possible; (b) that undesired spectral components in the earth station's transmitted signal should be minimized; (c) that time-asymmetry in the modulating waveform results in a DC- component; (d) that such a DC-component in the modulating waveform results in a data power loss because of AC-coupling in the modulator; (e) that, in addition to the power loss, time-asymmetry results in matched filter losses; (f) that the above losses should not exceed 0.1 dB; (g) that the out-of-band emissions resulting from the time-asymmetry in the modulating waveform can be reduced by additional filtering; recommends that, the symmetry of all baseband square wave modulating waveforms should be such that the mark-to-space ratio will lie between 0.98 and 1.02. _________________ NOTE: 1. This Recommendation is also filed as Rec. 401 (2.4.8) B-1 for the space-to-earth link. 2. Where Bi-Phase modulation is utilized, larger baseband signal losses, than are permitted by considering (f), may result. CCSDS 401 (2.2.6) B-1 Page 2.2.6-1 September 1989 2.3.1 RESIDUAL CARRIERS FOR LOW RATE TELEMETRY, SPACE-TO-EARTH LINKS The CCSDS, considering (a) that many space agencies own and/or operate earth stations for communication with spacecraft in which they have substantial investments; (b) that these earth stations contain receiving equipment employing phase-locked loops; (c) that conventional phase-locked loop receivers require a residual carrier component to operate properly; (d) that most space agencies use autotrack systems for Category A missions, which need a residual carrier; recommends that CCSDS agencies retain residual carrier receiving systems in their earth stations for use with missions having low rate telemetry requirements. CCSDS 401 (2.3.1) B-1 Page 2.3.1-1 January 1987 2.3.2 SUPPRESSED CARRIERS FOR HIGH RATE TELEMETRY, SPACE-TO- EARTH LINKS The CCSDS, considering (a) that present technology makes the implementation of suppressed carrier systems practicable; (b) that a comparison of carrier signal-to-noise ratios in a conventional residual carrier phase-locked loop with those in a suppressed carrier loop shows that the latter provides a substantial advantage over the former, frequently exceeding 10 dB; (c) that a comparison of data symbol errors occurring in a conventional residual carrier phase-locked loop system with those occurring in a suppressed carrier loop system shows that the latter's performance is no worse, and frequently is better, than that of the former; (d) that suppressed carrier systems lend themselves to compliance with PFD limits on the Earth's surface more readily than do residual carrier systems; (e) that some space agencies still use autotrack systems for their Category A missions, which need a residual carrier; recommends (1) that CCSDS agencies utilize suppressed carrier systems for space-to-earth communications when a residual carrier system would exceed the PFD limits on the Earth's surface; (2) that CCSDS agencies may provide a beacon for autotracking their Category A missions using suppressed carrier modulation. CCSDS 401 (2.3.2) B-1 Page 2.3.2-1 January 1987 2.3.3A EARTH STATION RECEIVER ACQUISITION FREQUENCY SWEEP RANGE, CATEGORY A The CCSDS, considering (a) that the space-to-earth link may be operated in either a coherent turnaround mode, or in a one-way mode; (b) that for the coherent turnaround mode, the Doppler frequency shift induced on both the earth-to-space and the space-to-earth links is the major factor to be considered in selecting the frequency sweep range; (c) that for the one-way mode, both the Doppler frequency shift induced on the space-to-earth link and the frequency stability of the spacecraft's oscillator are the major factors to be considered in selecting the frequency sweep range; (d) that the maximum rate of change of distance between the earth station and Category B spacecraft can reach values of up to 10 km/s; (e) that the minimum frequency stability found in Category A spacecraft reference frequency oscillators is about ñ 2 x 10-5; recommends (1) that CCSDS agencies' earth station receivers be capable of frequency sweep ranges of at least: ñ 150 kHz at 2 GHz ñ 600 kHz at 8 GHz (2) that CCSDS agencies provide a minimum sweep range that is consistent with their ability to predict the Doppler frequency shift. CCSDS 401 (2.3.3A) B-1 Page 2.3.3A-1 January 1987 2.3.3B EARTH STATION RECEIVER ACQUISITION FREQUENCY SWEEP RANGE, CATEGORY B The CCSDS, considering (a) that the space-to-earth link may be operated in either a coherent turnaround mode, or in a one-way mode; (b) that in the coherent turnaround mode, the Doppler frequency shift induced on both the earth-to-space and the space-to-earth links is the major factor to be considered in selecting the frequency sweep range; (c) that the effect on the radio link, resulting from variation in the columnar charged-particle content, is generally negligible; (d) that the maximum rate of change of distance between the earth station and Category B spacecraft can reach values of up to 35 km/s; (e) that the minimum frequency stability found in Category B spacecraft reference frequency oscillators is about 1 x 10-6; recommends that CCSDS agencies' earth station receivers be capable of frequency sweep ranges of at least: ñ 300 kHz at 2 GHz ñ 1 MHz at 8 GHz. CCSDS 401 (2.3.3B) B-1 Page 2.3.3B-1 January 1987 2.3.4A EARTH STATION RECEIVER ACQUISITION FREQUENCY SWEEP RATE, CATEGORY A The CCSDS, considering (a) that the space-to-earth link may be operated in either a coherent turn-around mode or in a one-way mode; (b) that in the coherent turn-around mode, the Doppler frequency rates induced on both the earth-to-space and the space-to-earth links are the major factors to be considered in selecting the earth station receiver's frequency sweep rate; (c) that in the one-way mode, the Doppler frequency rate on the space- to-earth link and the earth station receiver's phase locked loop bandwidth (2 BLO), with its resulting maximum permissible input frequency variation, are the major factors to be considered in selecting the sweep rate; (d) that the rate-of-change of velocity between the earth station and Category A spacecraft can reach values up to 380 m/s2 at orbital altitudes of 300 km, which results in frequency variation rates of approximately 3 kHz/s at 2 GHz and 10 kHz/s at 8 GHz in the one-way mode (or 6 kHz/s and 20 kHz/s respectively in the coherent turn- around mode); (e) that the earth station's receivers generally have phase locked loop bandwidths (2 BLO) in the range of 30 Hz to 2 kHz at their threshold; (f) that, for an acquisition probability of 0.9, the maximum permissible rate of input frequency variation for this type of earth station receiver is between 100 Hz/s and 400 kHz/s at its threshold; (g) that the earth station receiver's frequency sweep rate plus the spacecraft's Doppler frequency rate must not exceed the receiver's ability to achieve phase-locked operation; (h) that the acquisition time should be kept to a minimum for each mission phase; recommends that CCSDS agencies' earth station receivers operating in the 2 and 8 GHz bands should have a minimum frequency sweep rate not exceeding 100 Hz/s and a maximum frequency sweep rate of at least 420 kHz/s. CCSDS 401 (2.3.4A) B-1 Page 2.3.4A-1 September 1989 2.3.4B EARTH STATION RECEIVER ACQUISITION FREQUENCY SWEEP RATE, CATEGORY B The CCSDS, considering (a) that the space-to-earth link may be operated in either a coherent turnaround mode, or in a one-way mode; (b) that in the coherent turnaround mode, the Doppler frequency rates induced on both the earth-to-space and the space-to-earth links are the major factors to be considered in selecting the earth station receiver's frequency sweep rate; (c) that in the one-way mode, the Doppler rate on the space-to-earth link and the earth station receiver's phase-locked loop bandwidth (2 BLO), with its resulting maximum permissible input frequency variation, are the major factors to be considered in selecting the sweep rate; (d) that the rate of change of velocity between the earth station and category B spacecraft can reach values up to 10 m/s2; (e) that the earth station's receivers have phase-locked loop bandwidths (2 BLO) in the range of 1 Hz to 1 kHz at their thresholds; (f) that typical earth station receivers, operating in the 2 and 8 GHz bands, allow a maximum permissible rate of input frequency variation of between 1 Hz/s and 10 kHz/s; (g) that the receiver's frequency sweep rate, plus the orbital Doppler frequency rate, must not exceed the earth station receiver's ability to achieve phase-locked operation; (h) that the acquisition time should be kept to a minimum for each mission phase; (i) that a lower limit for the signal-to-noise ratio in the earth station receiver's phase-locked loop is approximately 8.5 dB; recommends that CCSDS agencies' earth station receivers, operating in the 2 and 8 GHz bands, should have a minimum sweep rate not exceeding 1 Hz/s and a maximum sweep rate of at least 10 kHz/s. CCSDS 401 (2.3.4B) B-1 Page 2.3.4B-1 January 1987 2.3.5 POLARIZATION OF SPACE-TO-EARTH LINKS The CCSDS, considering (a) that a linear electric field polarization on links from spacecraft, having nearly omnidirectional antenna patterns, may vary considerably with aspect angle; (b) that the aspect angle of a near-earth orbiting satellite varies greatly during a pass; (c) that for satellites having a stable linear polarization in the direction of the earth station (e.g., geostationary satellites with suitable attitude stabilization or satellites using tracking antennas), the propagation effects such as Faraday rotation may cause changes in the received polarization at lower carrier frequencies; (d) that many earth stations are equipped with polarization diversity receivers; (e) that many existing spacecraft TTC antenna designs provide circular polarization; recommends (1) that CCSDS agencies utilize LCP or RCP polarization for satellite TTC space-to-earth links unless sharing of equipment with payload functions requires a different approach; (2) that automatic polarization tracking should be used for reception of satellite signals wherever possible; (3) that polarization diversity reception should be used to meet the required system time constants at earth stations used for Category A missions. CCSDS 401 (2.3.5) B-1 Page 2.3.5-1 January 1987 2.3.6 RELATIONSHIP OF MODULATOR INPUT VOLTAGE TO RESULTANT RF CARRIER PHASE SHIFT The CCSDS, considering that a clear relationship between the modulating signal and the RF carrier's phase is desirable to avoid unnecessary ambiguity problems; recommends that a positive-going voltage at the modulator input should result in an advance of the phase of the radio frequency signal. NOTE: 1. This Recommendation is also filed as Rec. 401 (2.1.5) B-1. CCSDS 401 (2.3.6) B-1 Page 2.3.6-1 January 1987 2.3.7 EARTH STATION OSCILLATOR REFERENCE FREQUENCY STABILITY The CCSDS, considering (a) that most of the space agencies use a reference frequency standard to which the earth station's receiver and transmitter local oscillators are locked; (b) that the short term frequency stability of the local oscillator substantially determines the range rate measurement's accuracy for Category A missions; (c) that the long term frequency stability of the local oscillator substantially determines the range rate measurement's accuracy for Category B missions; (d) that it is desirable for many missions to determine range rate with an accuracy of 1 mm/s or better; (e) that the oscillator's frequency shall be sufficiently stable such that its effect upon the range rate measurement's error shall be significantly less than 1 mm/s; (f) that, in addition to the foregoing, the long term stability of the local oscillator is also determined by the drift permitted in the earth station's clock which should not exceed 10 microseconds per month; recommends (1) that the short term frequency stability (Allan Variance) shall be better than ñ 5 x 10 -13 for time intervals between 0.2 s and 100 s; (2) that for Category B missions and for timekeeping, the long term frequency stability shall be better than ñ 2 x 10 -12 for any time interval greater than 100 s. CCSDS 401 (2.3.7) B-1 Page 2.3.7-1 January 1987 2.3.8 RF CARRIER SUPPRESSION ON SPACE-TO-EARTH LINKS FOR RESIDUAL CARRIER SYSTEMS The CCSDS, considering (a) that high modulation indices may make a residual carrier difficult to detect with a conventional phase-locked loop receiver; (b) that, for sine wave modulation, the carrier suppression should not exceed 10 dB as otherwise the recoverable power in the data channel decreases; (c) that, for square wave modulation, increasing the carrier suppression above 10 dB can result in a performance improvement in the data channel provided that the additional demodulation losses, resulting from the reduced carrier power, are less than the resulting data power increase; (d) that, where an error-detecting/correcting code is used on the data channel, a carrier tracking loop signal-to-noise ratio below 15 dB will result in demodulation losses which exceed the data power increase obtained by using a carrier suppression above 10 dB; recommends (1) that, for sine wave modulation, the carrier suppression should not exceed 10 dB; (2) that, for square wave modulation, the carrier suppression may exceed 10 dB provided that the carrier tracking loop's signal-to- noise ratio remains above 15 dB. CCSDS 401 (2.3.8) B-2 Page 2.3.8-1 June 1993 RESERVED for RECOMMENDATION 401 (2.4.1) CCSDS 401 (2.4.1) B-1 Page 2.4.1-1 September 1987 2.4.2 MODULATING PCM WAVEFORMS FOR SUPPRESSED CARRIER SYSTEMS The CCSDS, considering (a) that interaction between data sidebands and their RF carrier causes undesirable performance degradation; (b) that suppressed carrier modulation schemes eliminate interaction between data sidebands and the RF carrier; (c) that the necessary bandwidth for a suppressed carrier system with NRZ modulation is less than for a residual carrier system using Manchester or subcarrier modulation schemes; (d) that the lack of a carrier reference at the demodulator results in a phase ambiguity of 180 degrees in the data; (e) that this phase ambiguity is unacceptable and must be removed either by providing periodic, recognizable bit patterns for polarity determination, or by using a modulation that is insensitive to polarity; (f) that DNRZ modulation is insensitive to polarity; (g) that DNRZ inherently produces doublet errors, but bit pattern polarity determination schemes can result in the loss of entire frames; (h) that some CCSDS member agencies use DNRZ suppressed carrier modulation in their relay satellites to reduce the necessary bandwidth while preventing data-carrier interaction; (i) that either NRZ-M or NRZ-S is an acceptable DNRZ modulation scheme; (j) that NRZ-M is currently in use; recommends (1) that suppressed carrier modulation schemes use NRZ-M waveforms; (2) that in convolutionally encoded systems requiring conversion between NRZ-L and NRZ-M, the conversion from NRZ-L take place before the input to the Viterbi encoder, and the conversion from NRZ-M to NRZ-L take place after the output from the Viterbi decoder in order to maximize performance. CCSDS 401 (2.4.2) B-1 Page 2.4.2-1 January 1987 2.4.3 SUBCARRIERS IN LOW BIT RATE RESIDUAL CARRIER TELEMETRY SYSTEMS The CCSDS, considering (a) that at low bit rates, interaction between data sidebands and the residual RF carrier causes a performance degradation; (b) that subcarrier modulation schemes eliminate interaction between data sidebands and the residual RF carrier; (c) that some space agencies presently utilize ranging systems whose minor tones are below 20 kHz and whose major tone is 100 kHz, while others are planning to do so in the near future; (d) that simultaneous ranging and telemetry operation should be possible; recommends (1) that CCSDS agencies use subcarriers with their residual carrier systems when transmitting low bit rates; (2) that the subcarrier be placed between the 20 kHz and 100 kHz ranging tones, or above the 100 kHz tone. CCSDS 401 (2.4.3) B-1 Page 2.4.3-1 January 1987 2.4.4 PSK MODULATION FOR TELEMETRY SUBCARRIERS The CCSDS, considering (a) that PSK modulation is a very efficient type of digital modulation because of its bit error performance; (b) that many space agencies presently utilize PSK subcarrier modulation techniques, while others are planning to do so in the near future; recommends that CCSDS agencies use PSK subcarrier modulation if a telemetry subcarrier is employed. CCSDS 401 (2.4.4) B-1 Page 2.4.4-1 January 1987 2.4.5 TELEMETRY SUBCARRIER WAVEFORMS The CCSDS, considering (a) that space agencies frequently employ subcarriers to separate data sidebands from the RF carriers; (b) that for Category A missions, it is more important to limit the occupied bandwidth while for Category B missions, it is more important to minimize the susceptibility to in-band interference; (c) that it is easier to generate square wave subcarriers; recommends (1) that for Category A mission telemetry transmissions, CCSDS agencies use sine wave subcarriers when they are modulated in the PSK mode; (2) that for Category B mission telemetry transmissions, CCSDS agencies use square wave subcarriers when they are modulated in the PSK mode. CCSDS 401 (2.4.5) B-1 Page 2.4.5-1 January 1987 2.4.6 TELEMETRY SUBCARRIER FREQUENCY STABILITY The CCSDS, considering (a) that the present use of subcarriers for modulating the space-to-earth RF links represents a mature technique for both Categories A and B missions and, therefore, is a well settled standard; (b) that modifications of this standard imply costly changes to space agencies' networks; recommends that spacecraft radio frequency subsystems generating telemetry subcarriers be designed with characteristics equal to or better than: Maximum Subcarrier Frequency Offset ñ (1 x 10 -4)fsc Minimum Subcarrier Frequency Stability ñ 1 x 10 -6 (short term) Minimum Subcarrier Frequency Stability ñ 1 x 10 -5 (long term) NOTES: 1. fsc = frequency of telemetry subcarrier. 2. Short term time intervals are less than or equal, 100 times the subcarrier's waveform period. CCSDS 401 (2.4.6) B-1 Page 2.4.6-1 January 1987 2.4.7 CHOICE OF PCM WAVEFORMS IN RESIDUAL CARRIER TELEMETRY SYSTEMS The CCSDS, considering (a) that NRZ waveforms rely entirely on data transitions for symbol clock recovery, and this recovery becomes problematical unless an adequate transition density can be guaranteed; (b) that due to the presence of the mid-bit transitions, Split Phase (SP) waveforms provide better properties for bridging extended periods of identical symbols after initial acquisition; (c) that convolutionally encoded data have sufficient data transitions to ensure symbol clock recovery in accordance with the CCSDS recommended standards; (d) that with coherent PSK subcarrier modulation, it is possible by adequate hardware implementation to bridge extended periods of identical symbols even when NRZ waveforms are used; (e) that NRZ waveforms without a subcarrier have a non-zero spectral density at the RF carrier; (f) that coherent PSK subcarrier modulated by NRZ data and using an integer subcarrier frequency to symbol rate ratio, as well as SP waveforms, have zero spectral density at the RF carrier; (g) that the ambiguity which is peculiar to NRZ-L and SP-L waveforms can be removed by adequate steps; (h) that use of NRZ-M and NRZ-S waveforms results in errors occurring in pairs; (i) that it is desirable to prevent unnecessary decoder node switching by frame synchronization prior to convolutional decoding (particularly true for concatenated convolutional Reed-Solomon coding); (j) that to promote standardization, it is undesirable to increase the number of options unnecessarily, and that for any proposed scheme, those already implemented by space agencies should be considered first; recommends (1) that for modulation schemes which use a subcarrier, the subcarrier to bit rate ratio should be an integer; (2) that in cases where a subcarrier is employed, NRZ-L should be used; (3) that for direct modulation schemes having a residual carrier, only Split Phase - Level (SP-L) waveforms should be used; (4) that ambiguity resolution should be provided. CCSDS 401 (2.4.7) B-1 Page 2.4.7-1 January 1987 2.4.8 SYMMETRY OF BASEBAND DATA MODULATING WAVEFORMS The CCSDS, considering (a) that the spacecraft's transmitter power should be used as efficiently as possible; (b) that undesired spectral components in the spacecraft's transmitted signal should be minimized; (c) that time-asymmetry in the modulating waveform results in a DC- component; (d) that such a DC-component in the modulating waveform results in a data power loss because of AC-coupling in the modulator; (e) that, in addition to the power loss, time-asymmetry results in matched filter losses; (f) that the above losses should not exceed 0.1 dB; (g) that the out-of-band emissions resulting from the time-asymmetry in the modulating waveform can be reduced by additional filtering; recommends that, the symmetry of all baseband square wave modulating waveforms should be such that the mark-to-space ratio will lie between 0.98 and 1.02. NOTE: 1. This Recommendation is also filed as Rec. 401 (2.2.6) B-1 for the earth-to-space link. 2. Where Bi-Phase modulation is utilized, larger baseband signal losses, than are permitted by considering (f), may result. CCSDS 401 (2.4.8) B-1 Page 2.4.8-1 September 1989 2.4.9 MINIMUM MODULATED SYMBOL TRANSITION DENSITY ON THE SPACE-TO-EARTH LINK The CCSDS, considering (a) that symbol clock recovery systems usually extract the clock's frequency from the received symbol transitions; (b) that a large imbalance between ones and zeros in the data stream could result in a bit-error-rate degradation in the symbol detection process; (c) that NRZ waveforms are widely used in standard modulation systems; (d) that NRZ waveforms require sufficient symbol transitions for symbol clock recovery; (e) that the tracking system loop bandwidth is usually less than, or equal to, one percent of the symbol rate; (f) that, for Category A, the specified degradation in bit error rate, due to symbol sync error, is usually less than 0.3 dB; (g) that, for Category B, the specified degradation in bit error rate, due to symbol sync error, is usually less than 0.1 dB; recommends (1) that the maximum string of either ones or zeros be limited to 64 bits; (2) that, for Category A, a minimum of 125 transitions occur in any sequence of 1000 consecutive symbols;1 (3) that, for Category B, a minimum of 275 transitions occur in any sequence of 1000 consecutive symbols;1 NOTE: 1. See: CCSDS Recommendation for Packet Telemetry, CCSDS 102-B-2, January 1987, or later issue and CCSDS Recommendation for Telemetry Channel Coding, CCSDS 101.0-B-2, January 1987, or later issue to determine the recommended method(s) for ensuring adequate symbol transition density. CCSDS 401 (2.4.9) B-1 Page 2.4.9-1 September 1989 2.4.10 CHANNEL INPUT AND CODING CONVENTIONS FOR QPSK SYSTEMS The CCSDS, considering (a) that a clear relation between digital information and the resulting RF carrier phase is necessary to reconstruct the digital data stream following reception and demodulation; (b) that the digital data format will conform to the CCSDS Recommendation for Packet Telemetry; (c) that some communications systems with high data rate transmission requirements use QPSK modulation; (d) that the phase states representing each of the possible dibit values should be judiciously chosen so that a phase error of 90 degrees can cause an error in no more than one bit; (e) that it should be possible to have two logically independent channels; (f) that in the case of a single data stream the odd and even bits should be forwarded to two independent channels; recommends (1) that the serial input digital data stream to QPSK systems be divided so that odd bits are modulated on the I-channel and even bits are modulated on the Q-channel. (2) that carrier phase states have the following meanings: - 0 degrees represents a "00" bit pair, - 90 degrees represents a "01" bit pair, - 180 degrees represents a "11" bit pair, - 270 degrees represents a "10" bit pair. CCSDS 401 (2.4.10) B-1 Page 2.4.10-1 September 1989 2.4.11 PHASE-AMBIGUITY RESOLUTION FOR QPSK MODULATION SYSTEMS 1 The CCSDS, considering (a) that resolution of phase ambiguities in the earth station's receiver is an inherent problem with systems using coherent Quaternary Phase-Shift-Keying (QPSK) modulation; (b) that coding conventions for QPSK systems are unambiguously defined in CCSDS Recommendation 401 (2.4.10); (c) that the phase ambiguity results from an inability of the receiver's carrier recovery circuitry to select the correct reference phase from the four possible stable lock points (Table 2.4.11-1); (d) that the phase-ambiguity can be resolved by using the techniques listed in Figure 2.4.11-1; (e) that the several methods for resolving the phase ambiguity depicted in Figure 2.4.11-1 are evaluated in Table 2.4.11-2; (f) that most space agencies currently employ differential encoding and synchronization (sync) markers for framed data transmission; (g) that any of the four possible phase states result in an unambiguously identifiable unique word pattern according to Table 2.4.11-1 which can be used to resolve the phase ambiguity; (h) that the sync markers already existing in the framed data transmission can be used as the unique words for resolving the phase ambiguity; recommends (1) that the sync marker(s), if available, shall be used to resolve the phase ambiguity; (2) that the differential encoding technique shall be used when no sync marker is available. NOTE: 1. Such systems employ a single, serial data stream and the channel ambiguity is resolved in accordance with CCSDS Recommendation 401 (2.4.10) B-1. CCSDS 401 (2.4.11) B-1 Page 2.4.11-1 May 1992 2.4.11 PHASE-AMBIGUITY RESOLUTION FOR QPSK MODULATION SYSTEMS (Continued) ANNEX TO RECOMMENDATION UŽŽŽŽŽŽŽŽŽŽŽŽŽ¨ 3 QPSK SYSTEM 3 AŽŽŽŽŽŽAŽŽŽŽŽŽU 3 UŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽAŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽ¨ 3 3 UŽŽŽŽŽŽŽAŽŽŽŽŽŽ¨ UŽŽŽŽŽŽAŽŽŽŽŽ¨ 3 UNCODED QPSK 3 3 CODED QPSK 3 3 SYSTEM 3 3 SYSTEM 3 3 3 3 3 AŽŽŽŽŽŽŽAŽŽŽŽŽŽU AŽŽŽŽŽŽAŽŽŽŽŽU 3 3 UŽŽŽŽŽŽŽŽŽŽAŽŽŽŽŽŽŽŽ¨ UŽŽŽŽŽŽŽŽŽAŽŽŽŽŽŽŽŽŽŽ¨ 3 3 3 3 UŽŽŽŽŽŽAŽŽŽŽŽŽŽ¨ UŽŽŽŽŽŽAŽŽŽŽŽŽ¨ UŽŽŽŽŽŽŽAŽŽŽŽŽŽ¨ UŽŽŽŽŽŽŽŽAŽŽŽŽŽŽŽŽŽ¨ 3 DIFFERENTIAL 3 3 UNIQUE WORD 3 3 DIFFERENTIAL 3 3 NON- DIFFERENTIAL 3 3 CODING 3 3 DETECTION 3 3 CODING 3 3 CODING 3 3 TECHNIQUE 3 3 TECHNIQUE 3 3 TECHNIQUE 3 3 TECHNIQUE 3 AŽŽŽŽŽŽŽŽŽŽŽŽŽŽU AŽŽŽŽŽŽŽŽŽŽŽŽŽU AŽŽŽŽŽŽŽAŽŽŽŽŽŽU AŽŽŽŽŽŽŽŽAŽŽŽŽŽŽŽŽŽU 3 3 UŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽŽU UŽŽŽŽŽŽŽŽŽŽU UŽŽŽŽŽŽŽŽŽŽAŽŽŽŽŽŽŽŽ¨ UŽŽŽŽŽŽŽŽŽAŽŽŽŽŽŽŽŽŽŽ¨ UŽŽŽŽŽŽAŽŽŽŽŽŽŽ¨ UŽŽŽŽŽŽAŽŽŽŽŽŽŽ¨ UŽŽŽŽŽAŽŽŽŽŽ¨ UŽŽŽŽŽŽAŽŽŽŽŽŽ¨ 3 DIFFERENTIAL 3 3 DIFFERENTIAL 3 3 THRESHOLD 3 3 UNIQUE WORD 3 3 INSIDE FEC 3 3 OUTSIDE 3 3 DECODER 3 3 DETECTION 3 3 CODEC 3 3 CODEC 3 3 TECHNIQUE 3 3 TECHNIQUE 3 AŽŽŽŽŽŽŽŽŽŽŽŽŽŽU AŽŽŽŽŽŽŽŽŽŽŽŽŽŽU AŽŽŽŽŽŽŽŽŽŽŽU AŽŽŽŽŽŽŽŽŽŽŽŽŽU FIGURE 2.4.11-1: LIST OF PHASE-AMBIGUITY RESOLUTION TECHNIQUES LEGEND: FEC : Forward-Error-Correcting CODEC: Encoder and Decoder Pair CCSDS 401 (2.4.11) B-1 Page 2.4.11-2 May 1992 2.4.11 PHASE-AMBIGUITY RESOLUTION FOR QPSK MODULATION SYSTEMS (Continued) ANNEX TO RECOMMENDATION (Continued) TABLE 2.4.11-1: RELATIONSHIPS BETWEEN THE TRANSMITTED AND RECEIVED DATA CARRIER RECEIVED DATA PHASE ERROR (DEGREES) IR QR 0 IT QT 90 -QT IT 180 -IT -QT 270 QT -IT NOTE: 1. The negative sign indicates the complement of the data. CCSDS 401 (2.4.11) B-1 Page 2.4.11-3 May 1992 2.4.11 PHASE-AMBIGUITY RESOLUTION FOR QPSK MODULATION SYSTEMS (Continued) ANNEX TO RECOMMENDATION (Continued) TABLE 2.4.11-2: SUMMARY OF THE SALIENT FEATURES OF THE PREFERRED TECHNIQUES PREFERRED BIT ERROR RATE ADVANTAGES & TECHNIQUES (BER) DEGRADATION DISADVANTAGE - REQUIRES UNIQUE WORDS UNIQUE WORD DETECTION NEGLIGIBLE - INCREASE COMPLEXITY - INCREASE BANDWIDTH DIFFERENTIAL CODING WITHOUT - SIMPLE TO IMPLEMENT FORWARD-ERROR-CORRECTING INCREASES BY APPROXIMATEL - CAN CAUSE DEGRADATION IN (FEC) Y THE A FACTOR OF TWO DETECTION OF THE TRANSMITTED SYNC MARKERS DIFFERENTIAL CODING INSIDE BIT SNR DEGRADATION IS AB - PROVIDES QUICK PHASE THE OUT AMBIGUITY FEC ENCODER AND DECODER PA 3 dB FOR CONVOLUTIONAL RESOLUTION IR CODE WITH R = «, K = 7 (CODEC) DIFFERENTIAL CODING OUTSIDE NEGLIGIBLE - REQUIRES RELATIVELY LONG THE FEC CODEC TIME TO RESOLVE THE PHASE AMBIGUITY - REQUIRES LESS BANDWIDTH - REQUIRES RELATIVELY LONG THRESHOLD DECODER NEGLIGIBLE TIME TO RESOLVE THE PHASE AMBIGUITY - DOES NOT PROVIDE AS MUCH CODING GAIN AS VITERBI AND SEQUENTIAL DECODERS CCSDS 401 (2.4.11) B-1 Page 2.4.11-4 May 1992 2.4.12A MAXIMUM PERMISSIBLE PHASE AND AMPLITUDE IMBALANCES FOR SUPPRESSED CARRIER (BPSK/QPSK) RF MODULATORS FOR SPACE-TO- EARTH LINKS, CATEGORY A The CCSDS, considering (a) that suppressed carrier modulation (PSK) is recommended by CCSDS [401 (2.3.2) B-1] for spacecraft telemetry transmissions in the 2 and 8 GHz bands when residual carrier modulation would exceed PFD limits on the earth's surface; (b) that the presence of unwanted discrete spectral lines in the received spectrum may degrade the receiver's performance; (c) that phase and amplitude imbalances in the modulated RF carrier, caused by imperfections in the PSK modulator, contribute to the generation of a spurious spectral line at the carrier's frequency which can be detrimental to the performance of a PSK system and which may exceed PFD constraints; (d) that a phase imbalance of less than 2 degrees and an amplitude imbalance of less than 0.2 dB will result in a carrier suppression of more than 30 dB, which is sufficient to protect terrestrial systems from excessive PFD; (e) that the above-mentioned figures can be achieved without excessive hardware complexity; recommends (1) that the phase imbalance between any two phase states of the modulated signal shall not deviate from the ideal value by more than 2 degrees; (2) that the amplitude imbalance between any two phase states of the modulated signal shall be less than 0.2 dB. CCSDS 401 (2.4.12A) B-1 Page 2.4.12A-1 May 1992 2.4.13B MAXIMUM PERMISSIBLE PHASE AND AMPLITUDE IMBALANCES FOR SPACECRAFT SUBCARRIER MODULATORS, CATEGORY B The CCSDS, considering (a) that the balanced modulator is widely used in phase-modulated residual carrier systems as the product modulator for modulating telemetry data on a subcarrier; (b) that imperfect subcarrier modulation, caused by phase and amplitude imbalances, results in subcarrier harmonics which, when modulated on the RF carrier, produce an interfering component at the carrier frequency; (c) that the interfering component at the RF phase modulator's output may be out of phase with respect to the RF residual carrier, making it undesirable; (d) that the magnitude of this interfering component is dependent upon the phase and amplitude imbalances present in the subcarrier modulator; (e) that, for a phase imbalance not exceeding 2 degrees and an amplitude imbalance not exceeding 0.2 dB, the RF carrier tracking loop is not significantly affected by the interfering component generated by these phase and amplitude imbalances; (f) that, in addition to the interfering component, the phase and amplitude imbalances can contribute to the generation of spurious spectral lines at the spacecraft transmitter's output; (g) that these spurious spectral lines can degrade the telemetry bit signal-to-noise ratio (SNR); (h) that the telemetry bit SNR degradation, due to phase and amplitude imbalances, can be considered as part of the detection loss and this loss is usually less than 0.1 dB; (i) that, for a phase imbalance not exceeding 2 degrees and an amplitude imbalance not exceeding 0.2 dB, the telemetry bit SNR degradation is negligible at bit-error-rates (BERs) less than 10 - 6; (j) that a subcarrier modulator having a phase imbalance of less than 2 degrees and an amplitude imbalance less than 0.2 dB can be implemented without excessive hardware complexity; recommends (1) that the maximum phase imbalance of the subcarrier modulator shall not exceed 2 degrees; (2) that the maximum amplitude imbalance of the subcarrier modulator shall not exceed 0.2 dB. CCSDS 401 (2.4.13B) B-1 Page 2.4.13B-1 June 1993 2.5.1A MINIMUM EARTH STATION GROUP DELAY CALIBRATION ACCURACY, CATEGORY A The CCSDS, considering (a) that earth station group delay calibrations must include all equipment used for ranging measurements; (b) that the path used for earth station group delay calibration is not always identical with the path used for ranging measurements; (c) that earth station group delay calibrations require frequency translation to close the loop between the earth station's transmitting and receiving equipment; (d) that frequency translation requires the use of a transponder or frequency translator which will not be in the path during ranging measurements; (e) that the group delay measurement error, exclusive of frequency translation, can reasonably be kept as low as 2 nanoseconds; (f) that the group delay measurement error of the frequency translation equipment can also be kept as low as 2 nanoseconds; (g) that, where a frequency translator is employed to close the loop between the earth station's transmitting and receiving equipment, the ranging tone modulation indices used for up- and/or down-link during calibrations are generally not the same as those used during ranging measurements; (h) that the group delay variation of the earth station receiver resulting from the use of different modulation indices does not exceed 4 nanoseconds; (i) that the calibration error due to spurious modulation in the earth station's equipment does not exceed 2 nanoseconds; recommends that the earth station's group delay be calibrated with an accuracy better than, or equal to, 10 nanoseconds for Category A missions. CCSDS 401 (2.5.1A) B-1 Page 2.5.1A-1 September 1989 2.5.2A MINIMUM EARTH STATION RANGING GROUP DELAY STABILITY, CATEGORY A The CCSDS, considering (a) that most space agencies use ranging measurements for spacecraft orbit or trajectory determination; (b) that a ranging accuracy of 10 meters is generally adequate to meet the orbit or trajectory determination accuracy required by Category A missions; (c) that the accuracy of the ranging measurement is dependent upon the following factors: - the accuracy with which the station has been located on a geodetic grid; - the accuracy with which the medium can be modeled; - the accuracy of the frequency and timing system; - the accuracy with which the ranging channel's group delay has been calibrated; - the ranging data noise; - the group delay variations between calibrations; (d) that the ground system's contribution to the total 10 meter ranging error can be limited to 30 percent of the total; (e) that the elapsed time between the ranging calibration and the actual measurement can be limited to 12 hours or less; recommends that the total group delay variation in the ground station ranging equipment, over any 12 hour period, shall not exceed 20 nanoseconds. CCSDS 401 (2.5.2A) B-1 Page 2.5.2A-1 September 1989 2.5.2B MINIMUM EARTH STATION RANGING GROUP DELAY STABILITY, CATEGORY B The CCSDS, considering (a) that most space agencies use ranging measurements for spacecraft orbit or trajectory determination; (b) that precision range measurements are frequently required to meet the scientific objectives of Category B missions; (c) that the ranging data can yield scientific information about the medium and other physical phenomena; (d) that the value of the information obtained from the ranging measurement for scientific purposes is directly related to its accuracy; (e) that to satisfy the needs of all users, the ranging system should be capable of measurement accuracies of three meters or better; (f) that the accuracy of the ranging measurement is dependent upon the following factors: - the accuracy with which the station has been located on a geodetic grid; - the accuracy with which the medium can be modeled; - the accuracy of the frequency and timing system; - the accuracy with which the ranging channel's group delay has been calibrated; - the ranging data noise; - the group delay variations between calibrations; (g) that, in order to meet the measurement accuracies set forth in (e) above, it is important to control the magnitude of the error sources listed in (f) above; (h) that group delay variations in the ground station ranging equipment, which occur between calibrations of that delay, should not exceed ten percent of the total error budget; (i) that the elapsed time between the ranging calibration and the actual measurement can be limited to 12 hours or less; (j) that short term variations in group delay affect range rate measurements which are sometimes required for range measurement; recommends (1) that the total group delay variation in the ground station ranging equipment, over any 12 hour period, shall not exceed 2 nanoseconds. (2) that the derivative of the group delay (in a mean square sense) with time is within ñ 0.1 mm/s. CCSDS 401 (2.5.2B) B-1 Page 2.5.2B-1 September 1989 2.5.3A MINIMUM SPACECRAFT RANGING CHANNEL GROUP DELAY STABILITY, CATEGORY A The CCSDS, considering (a) that most space agencies use ranging measurements for spacecraft orbit or trajectory determination; (b) that a distance measurement accuracy of 10 meters is generally adequate to meet the orbit or trajectory determination accuracies required by Category A missions; (c) that the highest frequency ranging signal determines the precision of the range measurement; (d) that the principal delay encountered by the highest frequency ranging signal results from the narrow band filter in the transponder's ranging channel; (e) that, in the absence of thermal noise, the spacecraft transponder's contribution to the total 10 meter ranging error should not exceed 15 percent of the total; (f) that transponder ranging channel phase linearity is desirable since it facilitates removing the range ambiguities; (g) that a linear phase response of transponder's ranging channel can be achieved with a four-pole Bessel bandpass filter having a one- sided bandwidth of 200 kHz and a group delay of 10 microseconds; (h) that a group delay stability of a few percent is easily achievable for such a filter; recommends (1) that the delay variation of the highest frequency ranging signal, which occurs in the spacecraft's transponder, shall not exceed ñ 50 nanoseconds; (2) that pre-launch calibrations, together with telemetered data (voltage, temperature, static phase error, etc.) be sufficient to permit calculation of the transponder's ranging channel group delay with an accuracy of ñ 5 nanoseconds at any time; (3) that recommendations (1) and (2) are applicable over the full range of Doppler frequencies, input signal level, temperatures, and voltages encountered during the mission's lifetime; NOTE: 1. For ranging transponder bandwidth, refer to Recommendation 401 (2.5.4A). CCSDS 401 (2.5.3A) B-1 Page 2.5.3A-1 September 1989 2.5.3B MINIMUM SPACECRAFT RANGING CHANNEL GROUP DELAY STABILITY, CATEGORY B The CCSDS, considering (a) that most space agencies use ranging measurements for spacecraft orbit or trajectory determination; (b) that a distance measurement accuracy of 3 meters is generally adequate to meet the orbit or trajectory determination accuracies required by Category B missions; (c) that the highest frequency ranging signal determines the precision of the range measurement; (d) that the principal delay encountered by the highest frequency ranging signal results from the narrow band filter in the transponder's ranging channel; (e) that, in the absence of thermal noise, the spacecraft transponder's contribution to the total 3 meter ranging error should not exceed 25 percent of the total; (f) that transponder ranging channel phase linearity is desirable since it facilitates removing the range ambiguities; (g) that a linear phase response of transponder's ranging channel can be achieved with a four-pole Bessel bandpass filter having a one- sided bandwidth of 3.5 MHz and a group delay of 600 nanoseconds; (h) that a filter group delay stability of a few percent is easily achievable; (i) that transponders with two or more space-to-earth links having frequency diversity provide a means for determining range measurement errors induced by charged particles if the group delay difference(s) between the transponder's ranging channels is known with great accuracy; recommends (1) that the delay variation of the highest frequency ranging signal, which occurs in the spacecraft's transponder, shall not exceed ñ 30 nanoseconds; (2) that pre-launch calibrations, together with telemetered data (voltage, temperature, static phase error, etc.) be sufficient to permit calculation of the transponder's ranging channel group delay with an accuracy of ñ 2.5 nanoseconds at any time; (3) that the variation in differential delay between any two channels in a single transponder be less than ñ 2 nanoseconds; (4) that the above recommendations are applicable over the full range of Doppler frequencies, input signal level, temperatures, and voltages encountered during the mission's lifetime; NOTE: 1. For ranging transponder bandwidth, refer to Recommendation 401 (2.5.4B). CCSDS 401 (2.5.3B) B-1 Page 2.5.3B-1 September 1989 2.5.4A RANGING TRANSPONDER BANDWIDTH FOR RESIDUAL CARRIER SYSTEMS, CATEGORY A The CCSDS, considering (a) that, for most missions, the ranging signals occupy a larger bandwidth than telecommand or housekeeping telemetry signals; (b) that it is important to limit the occupied bandwidth in the Category A mission frequency bands; (c) that sine-wave ranging modulation is used for limiting the occupied bandwidth; (d) that range measurement precision increases with the frequency of the highest frequency (major) ranging tone; (e) that most space agencies presently utilize a 100 kHz major tone as a compromise between range measurement precision and bandwidth occupancy; (f) that most space agencies currently employ tones at or above 4 kHz; (g) that the spacecraft transponder's ranging filter must reject d.c. and very low frequencies so that the residual carrier energy is not re-modulated on the return link; (h) that it is important to minimize earth-to-space link noise which is re-modulated on the space-to-earth link; (i) that high phase linearity of the spacecraft transponder's ranging channel filter over its bandwidth facilitates removing range ambiguities when multiple range tones are used; (j) that the ranging transponder's bandwidth can be adequately controlled using a 4-pole Bessel linear-phase bandpass filter which properly defines the attenuation roll-off characteristics; recommends (1) that spacecraft transponders incorporate a bandpass filter in their ranging channel; (2) that the transponder ranging channel's baseband frequency response be uniform within ñ 0.5 dB within the frequency range 3 kHz to 110 kHz; (3) that the transponder's ranging channel be designed to not deviate more than ñ 6 degrees from a linear phase-frequency relationship within the bandwidth stated in recommends (2). CCSDS 401 (2.5.4A) B-1 Page 2.5.4A-1 September 1989 2.5.4B RANGING TRANSPONDER BANDWIDTH FOR RESIDUAL CARRIER SYSTEMS, CATEGORY B The CCSDS, considering (a) that range measurement precision increases with the frequency of the highest frequency (major) range code component; (b) that some space tracking systems for Category B missions employ square-wave ranging modulation having range code component frequencies from 1 Hz to 1 MHz; (c) that other spacecraft tracking systems for Category B missions employ sine wave tones, which can be selected in frequency from 100 kHz to 1 MHz, which may be phase modulated by a square wave code; (d) that these systems are designed to bi-phase modulate the high frequency code component with the low frequency code components to reduce interference with the telecommand and telemetry signals; (e) that the ranging transponder's bandwidth required to accommodate the ranging codes described in (b) permit flexibility in the selection of the types of ranging codes and modulation techniques; (f) that the ranging transponder's bandwidth can be adequately controlled using a 4-pole Bessel linear-phase bandpass filter which properly defines the attenuation roll-off characteristics; (g) that some margin should be included in the transponder filter's bandwidth to ensure proper operation with the commonly used 1 MHz tone or code; recommends (1) that spacecraft transponders incorporate a bandpass filter in their ranging channel; (2) that the transponder ranging channel's baseband frequency response be uniform within ñ 0.5 dB within the frequency range 3 kHz to 1.1 MHz; (3) that the one-half power (-3 dB) bandpass frequencies of the transponder's ranging channel be greater than 3 MHz and less than 1 kHz; (4) that the transponder's ranging channel be designed to not deviate more than ñ 6 degrees from a linear phase-frequency relationship within the bandwidth stated in recommends (3); (5) that the one-sided equivalent noise bandwidth be limited to 3.5 MHz. CCSDS 401 (2.5.4B) B-1 Page 2.5.4B-1 September 1989 2.5.5A PN CODE PHASE SHIFT STABILITY REQUIRED IN SPACECRAFT SPREAD SPECTRUM REGENERATIVE RANGING TRANSPONDERS, CATEGORY A The CCSDS, considering (a) that most agencies use ranging measurements for spacecraft orbit or trajectory determination; (b) that Pseudo-Noise (PN) code sequences are used by some spacecraft transponders to make ranging measurements; (c) that, in the ranging mode, these transponders must synchronize an on-board PN code generator to the received PN code; (d) that, usually, the earth-to-space link's signal-to-noise ratio in the ranging code's tracking loop is sufficiently large so that the phase error in the spacecraft's code tracking loop is an insignificant part of the ranging measurement error; (e) that a 1-sigma distance measurement accuracy of 10 meters is generally sufficient to meet the orbit or trajectory determination requirements of Category A missions; (f) that the spacecraft transponder's contribution to the total 10 meter distance measurement error should not exceed 30 percent of the total; (g) that the variation of transponder's temperature is the principal cause of instability in the time delay and is normally measured and recorded prior to launch; recommends that the time delay of PN codes through a spacecraft's transponder should not vary from its calibrated, pre-launch value by more than 20 nanoseconds. CCSDS 401 (2.5.5A) B-1 Page 2.5.5A-1 September 1989 2.6.1 TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 2025 -- 2120 MHz AND 2200 -- 2300 MHz BANDS The CCSDS, considering (a) that a great number of space missions, which require coherency between the earth-to-space and space-to-earth links for development of navigational data, operate in the above frequency bands; (b) that for space missions which require coherency, a turnaround frequency ratio must be defined; (c) that many CCSDS agencies have used the 221/240 turnaround ratio in their space missions for many years; (d) that many CCSDS agencies have developed equipment using this ratio for their spacecraft and earth stations which represent a large financial investment; (e) that the 221/240 turnaround frequency ratio adequately translates the 2025 - 2120 MHz band to the 2200 - 2300 MHz band; recommends (1) that CCSDS agencies continue to use the 221/240 turnaround frequency ratio for Category A and Category B space missions which are operating in the above bands; (2) that this turnaround frequency ratio is only necessary for those space missions which require both cross support from other agencies' earth stations and coherency between the earth-to-space and space-to-earth links. CCSDS 401 (2.6.1) B-1 Page 2.6.1-1 January 1987 2.6.2 TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 7145 -- 7235 MHz AND 8400 -- 8500 MHz BANDS The CCSDS, considering (a) that a great number of space missions which require coherency between the earth-to-space and space-to-earth links for development of navigational data operate in the above frequency bands; (b) that for space missions which require coherency, a turnaround frequency ratio must be defined; (c) that some CCSDS agencies have used the 749/880 turnaround ratio for several years and others are planning its use for the near future; (d) that some CCSDS agencies have developed equipment using this ratio for their spacecraft and earth stations and others are planning to do so in the near future, representing a large financial investment; (e) that the 749/880 turnaround frequency ratio adequately translates the 7145 - 7235 MHz band to the 8400 - 8500 MHz band; recommends (1) that CCSDS agencies use the 749/880 turnaround frequency ratio for their Category A and Category B space missions operating in the 7145 - 7235 and 8400 - 8500 MHz bands; (2) that this turnaround frequency ratio is only necessary for those space missions which require both cross support from other agencies' earth stations and coherency between the earth-to-space and space-to-earth links. CCSDS 401 (2.6.2) B-1 Page 2.6.2-1 January 1987 2.6.3A TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 2025 -- 2110 MHz AND 8450 -- 8500 MHz BANDS, CATEGORY A The CCSDS, considering (a) that future Category A space missions will use earth-to-space links in the 2025 - 2110 MHz band in conjunction with space-to-earth links in the 8450 - 8500 MHz band; (b) that these space missions may require coherency between the earth-to-space and space-to-earth links for the development of navigational data; (c) that for space missions which require coherency, a turnaround frequency ratio must be defined; (d) that the two frequency bands under consideration differ regarding the available bandwidth; (e) that the lower and upper parts of the 2025-2110 MHz band are already rather densely occupied by long term missions and, consequently, they should be avoided; (f) that for reasons of standardization of the on-board receiver design, a ratio between the two bands under consideration should be chosen in such a way as to conserve the number "221" of the "221/240" ratio for 2 GHz downlink/uplink systems; (g) that for reasons of simplicity of on-board transmitter design, a ratio which can be divided down to small integers should be selected; recommends (1) that CCSDS agencies use a turnaround frequency ratio of 221/900 for systems operating in the 2075 - 2087 MHz and 8450 - 8500 MHz bands; (2) that this turnaround frequency ratio is only necessary for those space missions which require both cross support from other agencies' earth stations and coherency between the earth-to-space and space-to-earth links. CCSDS 401 (2.6.3) B-1 Page 2.6.3A-1 January 1987 2.6.4A TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 7190 -- 7235 MHz AND 2200 -- 2290 MHz BANDS, CATEGORY A The CCSDS, considering (a) that future Category A space missions will use earth-to-space links in the 7190 - 7235 MHz band in conjunction with space-to-earth links in the 2200 - 2290 MHz band; (b) that these space missions may require coherency between earth-to-space and space-to-earth links for the development of navigational data; (c) that for space missions which require coherency, a turnaround frequency ratio must be defined; (d) that the two frequency bands under consideration differ regarding the available bandwidth; (e) that the lower and upper parts of the 2200 - 2290 MHz band are already rather densely occupied by long term missions and, consequently, they should be avoided; (f) that in many cases, the 2 GHz transponder will not be modified, and the 7 GHz earth-to-space link can be considered as optional; (g) that a design goal of the 2/8 GHz transponder should be a simplicity of interfaces and system flexibility; (h) that similarity of the circuit layout with the transponders developed for the deep space frequency bands may make hardware reuse possible; recommends (1) that CCSDS agencies use a turnaround frequency ratio of 765/240 for systems operating in the 7190 - 7235 MHz and 2256 - 2270 MHz bands; (2) that this turnaround frequency ratio is only necessary for those space missions which require both cross support from other agencies' earth stations and coherency between the earth-to-space and space-to-earth links. CCSDS 401 (2.6.4) B-1 Page 2.6.4A-1 January 1987 2.6.5B TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 2110 -- 2120 MHz AND 8400 -- 8450 MHz BANDS, CATEGORY B The CCSDS, considering (a) that Category B space missions use earth-to-space links in the 2110 - 2120 MHz band in conjunction with space-to-earth links in the 8400 - 8500 MHz band; (b) that many of these space missions require coherency between the earth-to-space and space-to-earth links for the development of navigational data; (c) that for space missions which require coherency, a turnaround frequency ratio must be defined; (d) that for reasons of standardization of the on-board receiver design, a ratio between the two bands under consideration should be chosen in such a way as to conserve the number "221" of the "221/240" ratio for 2 GHz uplink/downlink systems; (e) that for reasons of simplicity of on-board transmitter design, a ratio which can be divided down to small integers should be selected; (f) that some CCSDS agencies utilize a turnaround frequency ratio of 221/880 and others are planning to do so in the near future; recommends (1) that CCSDS agencies use a turnaround frequency ratio of 221/880 for their Category B missions operating in the 2110 - 2120 MHz and 8400 - 8450 MHz bands; (2) that this turnaround frequency ratio is only necessary for those space missions which require both cross support from other agencies' earth stations and coherency between the earth-to-space and space-to-earth links. CCSDS 401 (2.6.5) B-1 Page 2.6.5B-1 January 1987 2.6.6B TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 7145 -- 7190 MHz AND 2290 -- 2300 MHz BANDS, CATEGORY B The CCSDS, considering (a) that Category B space missions will use earth-to-space links in the 7145 - 7190 MHz band in conjunction with space-to-earth links in the 2290 - 2300 MHz band; (b) that many of these space missions require coherency between the earth-to-space and space-to-earth links for the generation of navigational data; (c) that for space missions which require coherency, a turnaround frequency ratio must be defined; (d) that for reasons of standardization of on-board receiver design, a turnaround frequency ratio containing the number "749" of the "749/880" ratio for the 7 GHz uplink/8 GHz downlink systems should be selected; (e) that for reasons of standardization of on-board transmitter design, a turnaround frequency ratio containing the number "240" of the "221/240" ratio for 2 GHz uplink/downlink systems should be selected; recommends (1) that CCSDS agencies use a turnaround frequency ratio of 749/240 for Category B missions operating in the 7145 - 7190 MHz and 2290 - 2300 MHz bands; (2) that this turnaround frequency ratio is only necessary for those space missions which require both cross support from other agencies' earth stations and coherency between the earth-to-space and space-to-earth links. CCSDS 401 (2.6.6) B-1 Page 2.6.6B-1 January 1987 2.6.7B TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 7145 - 7190 MHz AND 31.8 - 32.3 GHz BANDS, CATEGORY B The CCSDS, considering (a) that Category B space missions use earth-to-space links in the 7145- 7190 MHz band in conjunction with space-to-earth links in the 31.8- 32.3 GHz band; (b) that many of these space missions require coherency between the earth-to-space and space-to-earth links for the generation of navigation data; (c) that for space missions which require coherency, a Transponder Turnaround Frequency Ratio (TTFR) that provides a maximum number of coherent channels must be defined; (d) that for reasons of standardization, of the on-board receiver design, a TTFR should be chosen in such a way as to conserve 749 as the numerator of the ratio for the 7 GHz uplink / 32 GHz downlink system 1; (e) that an odd number is selected as the uplink factor (numerator of the TTFR) and an even number is selected as the downlink factor (denominator of the TTFR) to prevent downlink harmonic interference with uplink signals; (f) that, if the denominator of the TTFR can be factored into prime numbers [...] 19, then conventional frequency multiplying devices, followed by band-pass filters, can be implemented; (g) that, if the difference between the numerator and the denominator of the TTFR can be factored into prime numbers [...] 19, then conventional frequency multiplying devices, followed by band-pass filters, can be implemented; (h) that the number of frequency multipliers should be reduced to minimize the delay in the spacecraft receiver's closed phase-locked- loop path; (i) that the denominator of the TTFR should be chosen to allow maximum Voltage Controlled Oscillator (VCO), Automatic Gain Control (AGC), and Diplexer implementation flexibility; (j) that the denominator of the TTFR should be chosen to generate a minimum number of channels that fall into the Inter-Satellite Service allocation in the 32-33 GHz band; recommends that CCSDS Agencies use a Transponder Turnaround Frequency Ratio of 749/3344 for Category B missions operating in the 7145-7190 MHz and the 31.8-32.3 GHz bands. NOTE: 1. See CCSDS Recommendations 401 (2.6.2) B-1 and 401 (2.6.6B) B-1. CCSDS 401 (2.6.7B) B-1 Page 2.6.7B-1 November 1994 2.6.8B TRANSPONDER TURNAROUND FREQUENCY RATIOS FOR THE 31.8 - 32.3 GHz AND 34.2 - 34.7 GHz BANDS, CATEGORY B The CCSDS, considering (a) that Category B space missions use earth-to-space links in the 34.2- 34.7 GHz band in conjunction with space-to-earth links in the 31.8- 32.3 GHz band; (b) that many of these space missions require coherency between the earth-to-space and space-to-earth links for the generation of navigation data; (c) that for space missions which require coherency, a Transponder Turnaround Frequency Ratio (TTFR) that provides a maximum number of coherent channels must be defined; (d) that for reasons of standardization, of the on-board receiver design, a TTFR should be chosen in such a way as to conserve 3344 as the denominator of the ratio for the 34 GHz uplink / 32 GHz downlink system 1; (e) that an odd number is selected as the uplink factor (numerator of the TTFR) and an even number is selected as the downlink factor (denominator of the TTFR) to prevent downlink harmonic interference with uplink signals; (f) that, if the denominator of the TTFR can be factored into prime numbers [...] 19, then conventional frequency multiplying devices, followed by band-pass filters, can be implemented; (g) that, if the difference between the numerator and the denominator of the TTFR can be factored into prime numbers [...] 19, then conventional frequency multiplying devices, followed by band-pass filters, can be implemented; (h) that the number of frequency multipliers should be reduced to minimize the delay in the spacecraft receiver's closed phase-locked- loop path; (i) that the denominator of the TTFR should be chosen to allow maximum Voltage Controlled Oscillator (VCO), Automatic Gain Control (AGC), and Diplexer implementation flexibility; (j) that the denominator of the TTFR should be chosen to generate a minimum number channels that fall into the Inter-Satellite Service allocation in the 32-33 GHz band; recommends that CCSDS Agencies use a Transponder Turnaround Frequency Ratio of 3599/3344 for Category B missions operating in the 34.2-34.7 GHz and the 31.8-32.3 GHz bands. NOTE: 1. See CCSDS Recommendations 401 (2.6.7) B-1. CCSDS 401 (2.6.8B) B-1 Page 2.6.8B-1 November 1994 RESERVED FOR RECOMMENDATIONS 2.6.9 THROUGH 2.6.11 14 -- 17 GHz AND 32 -- 34 GHz TRANSPONDER TURNAROUND FREQUENCY RATIOS CCSDS 401 (2.6.9-2.6.11) B-1Page 2.6.9 TO 2.6.11 November 1994 2.6.12 SPACECRAFT TRANSPONDER IF AND AGC AMPLIFIER BANDWIDTHS FOR COHERENT OPERATION The CCSDS, considering (a) that most space agencies utilize spacecraft receivers employing phase-locked loops; (b) that most of these receivers are implemented as double conversion superhetrodyne radios with two stage i.f. bandpass filters, and automatic gain controls (AGC); (c) that a spacecraft's transponder is said to be operating coherently if its receiver is phase-locked to a signal, fr , an earth station and the spacecraft's transmitted signal, ft , is a rational multiple of fr , such that: ft = (m/n)fr , where m and n are integer numbers and the ratio (m/n) is called the transponder turnaround frequency ratio; (d) that the predetection i.f. bandpass filters' bandwidths and the carrier AGC loop's bandwidth are very important in determining the spacecraft receiver's phase-locked loop operation; (e) that the predetection bandwidths must be neither too large nor too small because the former can result in a degraded signal-to-noise ratio while the latter produces false locks during acquisition of the earth-to-space link; (f) that for Category A missions, where the earth-to-space signal strength can vary both rapidly and substantially, it is the practice to design AGC loops with a fast response; (g) that for Category B missions, where the earth-to-space signal strength generally changes slowly and slightly, it is the practice to design AGC loops with a slow response; (h) that, when the spacecraft's receiver is operating in an unlocked mode, the AGC amplifier's gain is determined by the total received signal plus noise power while, when it is operating in a phase- locked mode, the AGC amplifier's gain is determined solely by the received carrier's signal power; recommends (1) that the spacecraft transponder's turnaround frequency ratios be selected from those contained in Section 2.6 of this book; (2) that the spacecraft's transponder have two-sided predetection filter bandwidths of not less than 250 kHz followed by a second filter of not less than 3 kHz; (3) that, for Category A missions, spacecraft transponders be designed to permit selection of the two-sided carrier AGC loop bandwidth over a range of at least 15 Hz to 45 Hz depending upon mission conditions; (4) that, for Category B missions, spacecraft transponders be designed to permit selection of the two-sided carrier AGC loop bandwidth over a range of at least 1 Hz to 3 Hz depending upon mission conditions; (5) that the spacecraft transponder's AGC include coherent and non- coherent detectors. CCSDS 401 (2.6.12) B-1 Page 2.6.12-1 September 1989 3.0 POLICY RECOMMENDATIONS Section 2 concerns itself with Recommendations pertaining to Radio Frequency and Modulation systems' technical characteristics. By contrast, this chapter focuses upon radio frequency spectrum usage. Rules governing a user's operations in the frequency bands are as important as the equipment's' technical specifications. As crowding of the RF spectrum increases, standards become an imperative to maintaining order. In a broad sense, the International Telecommunication Union (ITU) establishes high-level spectrum policy with its Radio Regulations. Here, the principal concern is to establish lower-level Recommendations promoting the most efficient use of the ITU's frequency allocations. These policies are intended to supplement, not supplant, those promulgated by the ITU. This goal is reached by increasing the relevance of specific ITU regulations to spacecraft communications. Each Recommendation begins with applicable provisions of the ITU's Radio Regulations as a foundation and provides additional guidelines for that particular application. By establishing the following agreements, the CCSDS agencies hope to significantly reduce spectrum congestion. Then, the potential for mutual interference in spacecraft communications should decrease accordingly. A significant number of new Recommendations are concerned with Policy. Filing all such Recommendations in a single section makes them difficult to locate and promotes disorder. Accordingly, there are now six Policy sub-sections: 3.1 Frequency Utilization 3.4 Operational Procedures 3.2 Power Limitations 3.5 Testing Recommendations 3.3 Modulation Methods 3.6 Spacecraft Systems These sub-sections are intended to be general categories into which Policy Recommendations can be filed and which will simplify a reader's task in locating specific items. CCSDS 401 B Page 3.0-1 June 1993 FREQUENCY UTILIZATION RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 3.1.1 2 GHz System Efficient use of 2 GHz band by Parameters satellite missions. 3.1.2 10 MHz Occupied BW Max Cat A telemetry bandwidth in 8 A GHz band. 3.1.3 > 10 MHz Occupied BW Cat A missions should use 13-15 GHz A band. 3.1.4 Constraints Cat A constraints on use of 14-17 A GHz bands. 3.1.5 31.8-32.3 ; 34.2- Reserved for Cat B missions. B 34.7 GHz 3.1.6 Channel Frequencies Cat B channel frequency plan for 2, B 7, and 8 GHz. CCSDS 401 (3.0) B Page 3.0-2 November 1994 POWER LIMITATIONS RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 3.2.1 EIRP Levels Limitations on earth-to-space link. CCSDS 401 (3.0) B Page 3.0-3 November 1994 MODULATION METHODS RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 3.3.1 Sine Wave; Square Cat A; Cat B ranging modulation Wave waveforms. 3.3.2 Spread Spectrum Cat A criteria for use of spread A spectrum. modulation. 3.3.3 OQPSK; QPSK Cat A criteria for use. A 3.3.4 Limit Tlm. Subcarrier Criteria for use of telemetry Use subcarriers. CCSDS 401 (3.0) B Page 3.0-4 November 1994 OPERATIONAL PROCEDURES RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 3.4.1 Simultaneous Rng, Design spacecraft for simultaneous Cmd, Tlm operations. 3.4.2 Measurement Methods Charged particle measurement methods. 3.4.3 Charged Particle Cat A, Optimal methods for single A Calibration station tracking. CCSDS 401 (3.0) B Page 3.0-5 November 1994 TESTING RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 3.5.1 Test Names Min spacecraft-earth station compatibility tests. CCSDS 401 (3.0) B Page 3.0-6 November 1994 SPACECRAFT SYSTEMS RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 3.6.1 Power Spectral Constraints on space-to-space links. A Density CCSDS 401 (3.0) B Page 3.0-7 November 1994 3.1.1 EFFICIENT UTILIZATION OF THE 2 GHz BANDS BY SATELLITE MISSIONS The CCSDS, considering (a) that frequency bands 2025 - 2110 and 2200 - 2290 MHz are shared co-equally by the following space services: Space Research, Space Operation, and Earth Exploration Satellite (EES); (b) that these bands constitute mission bands for the Space Research and EES services and tracking, telemetry, and telecommand (TTC) bands for other space services making use of the Space Operation service allocations; (c) that these bands are of prime importance for the satellite missions of CCSDS agencies and will remain so for many years to come as no comparable alternative frequency allocations are available; recommends that, in order to make maximum use of these bands for satellite missions of all kinds, appropriate technical and operational constraints be observed, particularly: i The TTC systems for geostationary satellites should be designed and constructed to the general characteristics contained in CCIR Report 678, Dubrovnik, 1986, as set forth in Table 3.1.1-1. Given the state-of-the-art in satellite receiver technology as demonstrated by numerous existing 2 GHz TTC systems, higher earth station EIRPs are not desired and will be detrimental to the effective use of the RF spectrum as well as the geostationary orbit. ii Space systems, which are designed to operate in mission bands other than 2025 - 2110 MHz and 2200 - 2290 MHz, but which utilize TTC systems within these bands, should limit the use of such TTC systems to launch, orbit insertion, and emergency operations in accordance with the definition of the Space Operation service (ITU/RR/25). By limiting the use of such TTC systems, the possibility of interference between spacecraft operating in the Space Operation, Space Research, and Earth Exploration Satellite (EES) services will be greatly reduced. iii With a view to facilitating sharing of the 2 GHz bands, TTC and data transmission systems on spacecraft operating in the Space Research and Earth Exploration Satellite services should also be designed in such a way that the occupied bandwidths in the earth-to-space and space-to-earth links, as well as earth stations' EIRPs, are kept to a minimum. CCSDS 401 (3.1.1) B-1 Page 3.1.1-1 January 1987 3.1.1 EFFICIENT UTILIZATION OF THE 2 GHz BANDS BY SATELLITE MISSIONS (Continued) TABLE 3.1.1-1 TYPICAL SYSTEM PARAMETERS AT 2 GHz MODE SYSTEM PARAMETERS SPACE OPERATIONS (up to geostationary altitude) Reception at Telemetry bandwidth 100 kHz earth station Tracking bandwidth 400 kHz G/T, earth stations Approx. 20 dB/K Transmission Telecommand bandwidth 100 kHz from earth Tracking bandwidth 400 kHz stations EIRP, earth station Approx. 65 dBW CCSDS 401 (3.1.1) B-1 Page 3.1.1-2 January 1987 3.1.2A USE OF THE 8450 -- 8500 MHz BAND FOR SPACE RESEARCH, CATEGORY A The CCSDS, considering (a) that the 8450 - 8500 MHz band contains the only primary worldwide allocation to the Space Research service below 40 GHz, affording it particularly good protection from interference; (b) that the total allocated bandwidth is limited to 50 MHz; (c) that CCIR Recommendation 610 sets the limit for Category A missions at 2,000,000 km instead of lunar distance as currently defined in the ITU Radio Regulations (cf. ITU/RR/169); (d) that space missions to the region between lunar distance and 2,000,000 km will need spectrum accommodation outside the deep space bands, in accordance with (c); (e) that space missions mentioned under (d) may have technical requirements, which can only be satisfied in the 8450 - 8500 MHz bands; (f) that certain space missions have a 2/8 GHz coherency requirement, determined by mission objectives; recommends (1) that space missions requiring an occupied bandwidth, as defined in ITU/RR/147, of more than 20% of the available bandwidth (i.e., in excess of 10 MHz) should not be approved for a frequency assignment in the 8450 - 8500 MHz band without detailed consideration of their requirements; (2) that space missions mentioned in (d), (e), and (f) above should be given priority for use of the 8450 - 8500 MHz band; (3) that CCSDS agencies approve space missions with bandwidth requirements in excess of 10 MHz in the 8450 - 8500 MHz band only on a case-by-case basis and impose, where necessary, operational limitations on their use of this band. CCSDS 401 (3.1.2A) B-1 Page 3.1.2A-1 January 1987 3.1.3A USE OF THE 13.25 -- 15.35 GHz BANDS FOR SPACE RESEARCH, CATEGORY A The CCSDS, considering (a) that frequency bands are allocated to the Space Research service between 13.25 and 15.35 GHz, i.e., 13.25 - 13.40 GHz (earth-to-space) 13.40 - 14.30 GHz (no direction indicated) 14.40 - 14.47 GHz (space-to-earth) 14.50 - 15.35 GHz (no direction indicated) (b) that these bands are allocated with a secondary status and consequently may not enjoy full protection from interference at all sites and all times; (c) that these bands were found feasible for use with near-earth satellites in CCIR Recommendation 364; (d) that a link near 15 GHz may provide about 1.5-2.5 dB improvement in the space-to-earth link compared to the current 8 GHz band, while a link near 33 GHz may provide 5.0-7.7 dB improvement compared to 8 GHz; (e) that the limits of power flux density on the earth's surface for the 13.4 - 15.35 GHz bands are specified by CCIR Recommendation 510-1 to be: -148 dB (W/m2) in any 4 kHz band for angles of arrival between 0 and 5 degrees above the horizontal plane; -148 + 0.5 (delta - 5) dB (W/m2) in any 4 kHz band for angles of arrival, delta (degrees) between 5 and 25 degrees above the horizontal plane; -138 dB (W/m2) in any 4 kHz band for angles of arrival between 25 and 90 degrees above the horizontal plane; (f) that these PFD limits allow operation of earth stations with G/Ts of typically 35-40 dB/K; CCSDS 401 (3.1.3A) B-1 Page 3.1.3A-1 January 1987 3.1.3A USE OF THE 13.25 -- 15.35 GHz BANDS FOR SPACE RESEARCH, CATEGORY A (continued) recommends that the 13.25 - 15.35 GHz frequency bands of the Space Research service be used for Category A satellites, particularly with those missions having requirements for large bandwidths, which cannot be accommodated in other frequency bands of this service (such as in the 2 and 8 GHz bands). NOTE: 1. The Tracking and Data Relay Satellite System (TDRSS) uses the 13.25 to 15.35 GHz band with the 13.4 to 14.0 GHz portion being used for space-to-earth and TDRSS-to-user (satellite) transmissions. This lower portion of the band is susceptible to interference from Category A missions and consequently should be used with due consideration to the TDRSS use. (Sharing of this portion of the band may be feasible in certain circumstances, e.g., if transmissions of the near-earth spacecraft are pointed at the earth only and are restricted to those parts of the orbit where no interference will be carried to the White Sands, NM TDRSS earth station.) CCSDS 401 (3.1.3A) B-1 Page 3.1.3A-2 January 1987 3.1.4A CONSTRAINTS ON THE USE OF THE 14.0 - 15.35 GHz AND THE 16.6 - 17.1 GHz BANDS FOR SPACE RESEARCH, CATEGORY A The CCSDS, considering (a) that some missions operating in the Space Research Service require very large bandwidths (e.g., spaceborne VLBI, Geodesy, and Geodynamics); (b) that bandwidth requirements in excess of 10 MHz are increasingly difficult to satisfy in the frequency bands allocated to the Space Research Service below 10 GHz; (c) that the 8450-8500 MHz band has been determined to be inappropriate for Category A missions requiring more than 10 MHz bandwidth [see Recommendation 401 (3.1.2A) B-1]; (d) that the 14.00-15.35 GHz band is densely occupied by the Fixed Service (14.30-15.35 GHz) and the earth-to-space links of the Fixed Satellite Service (14.0-14.8 GHz), consequently, assignment of earth-to-space links for the Space Research Service is difficult; (e) that the 16.6-17.1 GHz band is allocated to the Radiolocation Service (primary), and to the Space Research Service (deep space, earth-to-space, secondary); (f) that CCSDS Agencies currently have no plans to use the 16.6-17.1 GHz band for deep space missions operating in the Space Research Service; (g) that the sharing situation in the 14.00-15.35 GHz and the 16.6-17.1 GHz bands, where the Space Research Service has only secondary status, is difficult and does not lend itself to the use of classical modulation schemes which exhibit a high interference potential and which have a high susceptibility to interference; (h) that spectrum spreading modulation methods can considerably alleviate the sharing problems noted above; (i) that CCSDS Agencies should ensure compatibility between their operations in the 14.00-15.35 GHz and the 16.6-17.1 GHz bands; (j) that certain parts of the 14.00-15.35 GHz band have existing and planned assignments to data relay satellite (earth-to-space and space-to-space); recommends (1) that the 14.00-15.35 GHz band be used for space-to-earth transmissions of Category A missions operating in the Space Research Service 1; NOTE: 1. The 14.3-14.4 GHz and the 14.47-14.50 GHz bands are not allocated to Space Research Service and will have to be used in accordance with the provisions of RR 342. CCSDS 401 (3.1.4A) B-1 Page 3.1.4A-1 November 1994 3.1.4A CONSTRAINTS ON THE USE OF THE 14.0 - 15.35 GHz AND THE 16.6 - 17.1 GHz BANDS FOR SPACE RESEARCH, CATEGORY A (Continued) (2) that the 16.6-17.1 GHz band be used for earth-to-space transmissions of Category A missions operating in the Space Research Service; (3) that the spectrum of data transmissions in these bands be sufficiently spread so as to ensure adequate protection for services operating in the band; (4) that existing and planned frequency assignments for data relay satellites operating in the 14.00-15.35 GHz band be protected. CCSDS 401 (3.1.4A) B-1 Page 3.1.4A-2 November 1994 3.1.5B USE OF THE 31.8 -- 34.7 GHz BANDS FOR SPACE RESEARCH, CATEGORY B The CCSDS, considering (a) that as spectrum usage increases, the potential for radio frequency interference (RFI) becomes greater; (b) that telemetry links from missions in deep space, having very weak signals at the earth stations, are particularly susceptible to RFI; (c) that frequency bands above 15 GHz are currently less crowded than those below 15 GHz; (d) that allocated bands that are practicable with current or near future technology exist near 33 GHz, in particular: FREQUENCY ALLOCATIONS IN THE SPACE RESEARCH SERVICE FREQUENCY DIRECTION ALLOCATION STATUS BAND (GHz) 31.8 - 32.3 space-to-earth Secondary* 34.2 - 34.7 earth-to-space Secondary* (e) that a link near 15 GHz may provide about 1.5-2.5 dB improvement in the space-to-earth link compared to the current 8 GHz band, while a link near 33 GHz may provide 5.0-7.7 dB improvement compared to 8 GHz; (f) that a link near 15 GHz may provide about 5 dB improvement in the earth-to-space link compared to the current 7 GHz band, while a link near 33 GHz may provide an improvement of 10 dB compared to 7 GHz; (g) that the allocations near 15 GHz and near 33 GHz are secondary; however, the 33 GHz allocation is primary in the U.S., Spain, and Australia, providing it with more protection from interference than is provided to the 15 GHz band; * Primary for deep space in the U.S., Spain, and Australia. Primary for space research in Bulgaria, Cuba, Hungary, Mongolia, Poland, the German Democratic Republic, Czechoslovakia, and the U.S.S.R. CCSDS 401 (3.1.5B) B-1 Page 3.1.5B-1 January 1987 3.1.5B USE OF THE 31.8 -- 34.7 GHz BANDS FOR SPACE RESEARCH, CATEGORY B (Continued) (h) that further consideration will have to be given to sharing considerations for either the 15 or 33 GHz bands. However, the 33 GHz band is somewhat better protected; recommends (1) that the frequency band: 31.8 - 32.3 GHz be utilized for Space Research (space-to-earth, Category B only); 34.2 - 34.7 GHz be utilized for Space Research (earth-to-space, Category B only); (2) that CCSDS agencies utilize the bands near 33 GHz for communications with Category B missions in preference to those allocated to deep space near 13 and 17 GHz; (3) that channel plans and transponder turnaround frequency ratios be developed as soon as possible linking the bands near 33 GHz to the 2, 7, and 8 GHz, Category B bands; (4) that further consideration be given to the allocation status and the study of sharing criteria for the 31.8 - 32.3 and 34.2 - 34.7 GHz bands. CCSDS 401 (3.1.5) B-1 Page 3.1.5B-2 January 1987 3.1.6B CHANNEL FREQUENCY PLAN FOR 2, 7, AND 8 GHZ, CATEGORY B The CCSDS, considering (a) that channel frequency plans for Category B missions exist for the 2, 7, and 8 GHz bands while others are being developed for the 32 and 34 GHz bands; (b) that the sets of channel frequency pairs in these existing plans are based upon the recommended turnaround ratios; (c) that members of the Space Frequency Coordination Group (SFCG) have resolved to select frequencies for their Category B missions from the existing channel frequency plans; (d) that most past, existing, and planned Category B missions have assigned frequencies that were selected on the basis of these existing channel frequency plans; (e) that CCSDS agencies conducting Category B missions have coordinated the selection of frequencies from those embodied in the existing channel frequency plans in order to avoid interference between missions; recommends (1) that CCSDS agencies select frequencies for their Category B missions operating in the 2, 7, and 8 GHz bands from the channel frequency plan contained in Table 3.1.6B-1; (2) that frequency selection be coordinated with an appropriate organization, such as the SFCG, to ensure the orderly use of the channel frequency plan. CCSDS 401 (3.1.6B) B-1 Page 3.1.6B-1 January 1987 3.1.6B CHANNEL FREQUENCY PLAN FOR 2, 7, AND 8 GHZ, CATEGORY B (Continued) TABLE 3.1.6B-1: CHANNEL CENTER FREQUENCIES 2110 - 2120 MHz 2290 - 2300 MHz 7145 - 7190 MHz 8400 - 8450 MHz Uplink Channel Downlink Channel Uplink Channel Downlink Channel Center Frequency Center Frequency Center Frequency Center Frequency Channel (MHz) (MHz) (MHz) (MHz) 1 2290.185185 7147.286265 2 2290.555556 7148.442131 3 2290.925926 7149.597994 4 2291.296296 7150.753857 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5* 2110.243056 2291.666667 7151.909724 8402.777780 6 2110.584105 2292.037037 7153.065587 8404.135803 7 2110.925154 2292.407407 7154.221450 8405.493826 8 2111.266204 2292.777778 7155.377316 8406.851853 9 2111.607253 2293.148148 7156.533179 8408.209876 10 2111.948303 2293.518519 7157.689045 8409.567903 11 2112.289352 2293.888889 7158.844908 8410.925927 12 2112.630401 2294.259259 7160.000771 8412.283950 13 2112.971451 2294.629630 7161.156637 8413.641977 14 2113.312500 2295.000000 7162.312500 8415.000000 15 2113.653549 2295.370370 7163.468363 8416.358023 16 2113.994599 2295.740741 7164.624229 8417.716050 17 2114.335648 2296.111111 7165.780092 8419.074073 18 2114.676697 2296.481481 7166.935955 8420.432097 19 2115.017747 2296.851852 7168.091821 8421.790124 20 2115.358796 2297.222222 7169.247684 8423.148147 21 2115.699846 2297.592593 7170.403550 8424.506174 22 2116.040895 2297.962963 7171.559413 8425.864197 23 2116.381944 2298.333333 7172.715276 8427.222220 24 2116.722994 2298.703704 7173.871143 8428.580248 25 2117.064043 2299.074074 7175.027006 8429.938271 26 2117.405092 2299.444444 7176.182868 8431.296294 27 2117.746142 2299.814815 7177.338735 8432.654321 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 28 2118.087191 7178.494597 8434.012344 29 2118.428241 7179.650464 8435.370371 30 2118.769290 7180.814838 8436.738395 31 2119.110339 7181.962190 8438.086418 32 2119.451389 7183.118056 8439.444445 33 2119.792438 7184.273919 8440.802468 34** 7185.429783 8442.160493 35 7186.585617 8443.518517 36 7187.741511 8444.876542 37 7188.897375 8446.234566 38 8447.592591 39 8448.950616 * Channels 5-27 are fully coherent in all four bands. ** Channels 34-39 frequencies are estimates only. CCSDS 401 (3.1.6B) B-1 Page 3.1.6B-2 January 1987 3.2.1 LIMITATIONS ON EARTH-TO-SPACE LINK POWER LEVELS The CCSDS, considering (a) that spectral occupation of frequency bands used by space agencies is increasing rapidly; (b) that in many cases the same frequencies will be shared by several spacecraft; (c) that excessive EIRP levels radiated from earth stations will make frequency sharing increasingly difficult and result in inefficient use of the radio frequency spectrum; (d) that Pc/No, Eb/No, and the minimum signal level required due to the limitations of the receiver's dynamic range determine the required EIRP from the earth station; (e) that the required signal level at the spacecraft's receiver input is frequently the dominant parameter determining the EIRP required from the earth station; recommends (1) that CCSDS agencies limit the EIRP levels on the earth-to-space links to those realistically required for safe spacecraft operation which can be achieved in the following ways: - CCSDS agencies avoid using high power transmitters having a fixed output and adjust their transmitted power level to the minimum needed to meet project requirements; - CCSDS agencies obtain the required EIRP by using reasonable antenna diameters in order to reduce both sidelobe radiation and transmitter power levels (Guideline: antenna diameter/RF wavelength equal to or greater than 70); - CCSDS agencies place CCIR Recommendation 465-1 as a requirement in antenna specifications; (1) that spacecraft equipment designers should endeavor to provide equal margins for Pc/No, Eb/No and the minimum signal required to fall within the receiver's dynamic range. CCSDS 401 (3.2.1) B-1 Page 3.2.1-1 January 1987 3.3.1 OPTIMAL RANGING MODULATION WAVEFORMS FOR SIMULTANEOUS RANGING, TELECOMMANDING, AND TELEMETRY OPERATIONS The CCSDS, considering (a) that two-way transmissions are employed for making range measurements to a distant spacecraft; (b) that telecommand and telemetry signals are phase shift-keyed onto the subcarriers and then phase-modulated onto a sinusoidal residual RF carrier [see Recommendations 401 (2.1.1) B-1, 401 (2.4.3) B-1, 401 (2.4.4) B-1]; (c) that telemetry signals may also be directly modulated on the RF carrier in conformance with Recommendation 401 (2.4.7) B-1; (d) that sine-wave subcarriers are recommended for the telecommand channel [see Recommendation 401 (2.2.2) B-1]; (e) that sine-wave subcarriers are recommended for Category A mission's telemetry channels, and square-wave subcarriers are recommended for Category B mission's telemetry channels [see Recommendation 401 (2.4.5) B-1]; (f) that, for simultaneous telecommand and ranging on the earth-to- space link, the telecommand performance suffers some degradation due to command-ranging cross-modulation components; (g) that, for simultaneous telemetry and ranging on the space-to-earth link, the telemetry performance may be degraded due to interference from the filtered versions of the uplink ranging, feed-through telecommand, cross-modulation components and noise; (h) that the timing offset due to different clocks between the telecommand and telemetry may cause serious telemetry bit error rate (BER) degradation; (i) that the telecommand BER performance is virtually identical for either sine wave or square wave ranging modulation; (j) that, for Category B missions, the telemetry BER performance is insensitive to the type of ranging waveforms used when operated simultaneously with the ranging on the space-to-earth link; (k) that the use of a square-wave ranging signal makes the telemetry BER performance more susceptible to data-to-data interference (resulting from the timing offset due to different clocks between the telecommand and telemetry) than the sine-wave ranging; (l) that, for Category A missions, the telemetry BER performance is sensitive to the timing offset when operated simultaneously with either a square-wave or sine-wave ranging signal; (m) that for Category B missions, it is important to minimize the required transmitted power level on the space-to-earth link; CCSDS 401 (3.3.1) B-1 Page 3.3.1-1 September 1989 3.3.1 OPTIMAL RANGING MODULATION WAVEFORMS FOR SIMULTANEOUS RANGING, COMMANDING, AND TELEMETRY OPERATIONS (Continued) (n) that for Category A missions, it is necessary to minimize the adjacent channels interference; (o) that the use of a sine-wave ranging signal will minimize the occupied bandwidth; recommends (1) that, for Category B mission's earth-to-space links, either a sine wave or a square wave ranging signal may be used when operated simultaneously with the telecommand; (2) that, for Category A mission's earth-to-space links, sine wave ranging shall be used when operated simultaneously with the telecommand; (3) that, for Categories A and B mission's space-to-earth links, sine wave ranging should be used when operated simultaneously with the telemetry; CCSDS 401 (3.3.1) B-1 Page 3.3.1-2 September 1989 3.3.2A CRITERIA FOR USE OF DIRECT SEQUENCE SPREAD SPECTRUM MODULATION, CATEGORY A The CCSDS, considering (a) that frequency bands must often be shared between several users which can result in mutual interference; (b) that such mutual interference can result in significant link degradation or even unusable links for certain periods of time; (c) that spread spectrum systems can be designed to tolerate a high level of interference from other communications systems; (d) that, in some cases, spread spectrum modulation can assist in meeting the PFD limits set forth in the International Telecommunication Union's (ITU) Radio Regulations; (e) that direct sequence spread spectrum systems can be designed to provide ranging measurements by using the spreading code which eliminates the need for a separate ranging signal; recommends (1) that direct sequence spread spectrum modulation be used in any of the following cases: - where the intra-service sharing conditions are such that other modulation methods will not provide the required performance or mutual compatibility with other transmissions assigned to the same frequency band; - where the inter-service sharing conditions are such that the susceptibility to actual or potential interference from transmissions in other services assigned to the same frequency band cannot be kept within acceptable limits by other modulation methods; - where the power flux density limits, as set forth in the ITU Radio Regulations, Article 28, cannot be met using other methods; (2) that spread spectrum systems shall be designed to minimize unwanted emissions in the same allocated frequency band; (3) that unwanted emissions generated by spread spectrum systems shall conform with applicable protection criteria of radio communications services in other frequency bands. CCSDS 401 (3.3.2A) B-1 Page 3.3.2A-1 September 1989 3.3.3A CRITERIA FOR USE OF QPSK MODULATION IN SUPPRESSED CARRIER SYSTEMS, CATEGORY A The CCSDS, considering (a) that efficient use of RF spectrum resources is becoming increasingly important; (b) that suppressed carrier systems are more bandwidth and power efficient than are residual carrier systems; (c) that OQPSK systems are less sensitive to non-linear channel effects than are standard QPSK systems; (d) that sync word detection hardware for phase ambiguity resolution is simpler in a OQPSK system than is the case with a standard QPSK system; (e) that standard QPSK and OQPSK systems are widely used modulation techniques in bandwidth limited systems; recommends that OQPSK or standard QPSK modulation be used in communications systems operating at frequencies where the available bandwidth is limited (e.g., in the 2 and 8 GHz bands); CCSDS 401 (3.3.3A) B-1 Page 3.3.3A-1 September 1989 3.3.4 USE OF SUBCARRIERS ON SPACECRAFT TELEMETRY CHANNELS The CCSDS, considering (a) that frequency bands allocated to the space science services are becoming more congested as space missions multiply, data rates increase, and other services enter these bands; (b) that it is becoming imperative that all users restrict their transmissions to the minimum bandwidth necessary to achieve the communication; (c) that most space agencies have been using subcarriers on their telemetry channels to separate various signals and to ensure that the modulated data's RF spectrum does not overlap the residual RF carrier's frequency causing interference to the earth station receiver's carrier tracking loop; (d) that the bandwidth of systems using subcarrier modulation is substantially greater than that needed to communicate the information and is often increased as the subcarrier frequency-to- symbol rate ratio becomes larger; (e) that subcarriers required for low rate housekeeping telemetry data can still result in a small bandwidth if low subcarrier-to-symbol rate ratios are used; (f) that alternative modulation schemes are available which are more bandwidth and power efficient; (g) that subcarriers are not required to separate telemetry data streams because several channels can be present simultaneously on a single RF carrier if Virtual Channels are used in accordance with the CCSDS Recommendation for Packet Telemetry (CCSDS 102.0-B-2); (h) that eliminating subcarriers simplifies both the spacecraft's and the earth station's data system complexity and reduces losses in the modulation-demodulation process; recommends (1) that space agencies use the most bandwidth-efficient modulation scheme practicable for their mission; (2) that space agencies avoid the use of telemetry subcarriers except when they are required for technical reasons; (3) that, if a subcarrier is required, the subcarrier frequency-to- telemetry symbol-rate ratio be minimized. CCSDS 401 (3.3.4) B-1 Page 3.3.4-1 November 1994 3.4.1 SIMULTANEOUS TELECOMMAND, TELEMETRY, AND RANGING OPERATIONS The CCSDS, considering (a) that most space agencies use ranging measurements for spacecraft orbit or trajectory determination; (b) that precision range measurements are frequently required to meet the scientific objectives of the mission; (c) that the ranging data can yield scientific information about the medium and other physical phenomena; (d) that the value of the information obtained from the ranging measurement for scientific purposes is directly related to its accuracy; (e) that the earth stations tend to be large, complex, and expensive to construct and to operate; (f) that it is desirable to minimize the amount of earth station time required for the support of missions; (g) that the quantity of telecommands transmitted to a spacecraft may be sufficiently large that it is desirable to have simultaneous telecommand and ranging operations; (h) that telemetry transmissions are generally continuous and an interruption for ranging operations may result in the loss of valuable data; (i) that the amount and accuracy of ranging required for missions makes it desirable to preserve an ability for simultaneous telecommand, telemetry, and ranging operations; recommends that all CCSDS agencies design their spacecraft to permit simultaneous telecommand, telemetry, and ranging operations. CCSDS 401 (3.4.1) B-1 Page 3.4.1-1 September 1989 3.4.2 CHARGED PARTICLE MEASUREMENTS IN THE TELECOMMUNICATIONS PROPAGATION PATH The CCSDS, considering (a) that the telecommunication system's performance can be affected by the columnar content of charged particles in the propagation path; (b) that charged particles in the propagation path can result in errors in the range and range rate measurements reducing navigation accuracy; (c) that navigation accuracy requirements can be very high for some Category B missions; (d) that the four regions through which a telecommunications signal may pass which contain charged particles are: the Earth's ionosphere, the interplanetary medium, the planetary ionosphere, and the solar corona; (e) that the Sun-Earth-Probe (SEP) angle is important in selecting a means for measuring charged particles; (f) that geostationary satellites are not useful for measuring charged particle content for regions beyond the Earth's ionosphere; (g) that Differenced Range vs. Integrated Doppler (DRVID) only measures variations in the total columnar electron content; (h) that method(s) utilized for measuring the charged particle content in the propagation path depends upon the region involved; (i) that Figure 3.4.2-1 shows alternative spacecraft tracking methods which provide information about charged particles in the propagation path; recommends (1) that CCSDS agencies utilize the appropriate methods in Table 3.4.2- 1 to measure charged particles in the propagation path for the specified operating modes. (2) that CCSDS agencies utilize the methods and signal sources in Table 3.4.2-2 to measure charged particles in the named regions and to correct the specified data. CCSDS 401 (3.4.2) B-1 Page 3.4.2-1 September 1989 3.4.2 CHARGED PARTICLE MEASUREMENTS IN THE TELECOMMUNICATIONS PROPAGATION PATH (Continued) [IMAGE] FIGURE 3.4.2-1: POSSIBLE TRACKING MODES 6485-23012Gn CCSDS 401 (3.4.2) B-1 Page 3.4.2-2 September 1989 3.4.2 CHARGED PARTICLE MEASUREMENTS IN THE TELECOMMUNICATIONS PROPAGATION PATH (Continued) TABLE 3.4.2-1: RECOMMENDED CHARGED PARTICLE CALIBRATION METHODS | TRACKING MODE | FARADAY ROT | DRVID | DUAL FREQ | | (see Figure 3.4.2A-1) | user s/c | geo sat | user s/c | user s/c | geo sat |slic(b) | | | | | | | | | | I.1a (1-way range) | X | X | | X | X | X | | | | | | | | | | I.1b (1-way Doppler) | X | X | X | X | X | X | | | | | | | | | | I.2.1a (2-way coh Rng) | X | X | | X | X | X | | | | | | | | | | I.2.1b (2-way coh Dop) | X | X | X | X | X | X | | | | | | | | | | I.2.2.a (2-way non-coh Rng) | | | | | | | | | | | | | | | | I.2.2b (2-way non-coh Dop) | | | X | | | | | | | | | | | | | II.1 Alternate Rng | X | X | | X | X | X | | | | | | | | | | II.2 Simultaneous Rng | X | X | | X | X | X | | | | | | | | | | II.3 S/C VLBI | X | X | | (a) | | X | | | | | | | | | | II.4a (2-way; 3-way Rng) | X | X | | X | X | X | | | | | | | | | | II.4b (2-way; 3-way Dop) | X | X | X | X | X | X | | | | NOTES: (a) is applicable to 2/8 GHz downlink only. | | (b) slic is satellite L-band Ionospheric Calibration. | | | TABLE 3.4.2-2: APPLICABILITY OF CALIBRATION METHODS | | |EARTH's | Beyond | | RANGE | | CALIBRATION |SOURCE | IONO- | IONO- | RANGE | RATE | | METHOD | USED |SPHERE |SPHERE | ERROR | ERROR | | FARADAY | S/C | X | | X(1) | X(1) | | ROTATION | Geo Sat | X | | X(2) | X(2) | | | S/C | X | X | X(3) | X(3) | | DUAL | Geo Sat | X | | X(2) | X(2) | | FREQUENCY | slic | X | | X(2) | X(2) | | DIFFERENCED RANGE | S/C | X | X | | | | vs. INTEGRATED DOP | Geo Sat | | | | | | | | NOTES: (1) should not be used for SEPs below 5 degrees. | | (2) must translate ray path to user S/C line of sight. | | (3) 2/8 GHz downlink only, inaccurate below SEP = 20 deg. | | | CCSDS 401 (3.4.2) B-1 Page 3.4.2-3 September 1989 3.4.3A OPTIMAL CHARGED PARTICLE CALIBRATION TECHNIQUES FOR RANGING DATA UNDER VARIOUS PROPAGATION CONDITIONS, SINGLE STATION TRACKING, CATEGORY A The CCSDS, considering (a) that the Total (Columnar) Electron Content (TEC) in the telecommunications ray path may be a function of both the spacecraft-earth station distance and the Sun-Earth-Probe (SEP) angle; (b) that, for Category A missions, the Round-Trip-Light-Time (RTLT) is always less than or equal to 13.3 seconds; (c) that, for RTLTs typically found with Category A missions, the TEC results primarily from the Earth's Ionosphere and is substantially independent of SEP angle; (d) that for short telecommunications RTLTs, the TEC is relatively invariant with time; (e) that, for Category A missions, the charged-particle environment can be assumed to be identical for both up and down links because of the short RTLTs; (f) that it may be necessary to calibrate the TEC for Category A missions which have very high navigational or orbit positional accuracy requirements; (g) that charged particle calibration techniques such as dual frequency up/dual frequency down (or round-trip dual frequency), single frequency up/dual frequency down, and Faraday rotation can be used to calibrate the range data; (h) that, for Category A missions, use of the round-trip dual frequency technique does not offer any significant improvements in range error uncertainty when compared to a single frequency X-band (or higher) uplink/dual frequency downlink technique (see Figure 3.4.3A- 1); (i) that the use of Faraday Rotation technique may not provide the desired accuracy because it may require a mapping of total columnar electron content (TEC) to the line-of-sight for range error calibration; (j) that selection of the simplest qualified charged particle calibration technique should be based upon the (1) maximum permissible range error and RMS range error uncertainty, (2) minimum hardware requirements, and (3) requirement for a capability to calibrate the range data errors resulting from the variation of the total columnar electron content; recommends (1) that space agencies use the single frequency up/dual frequency down technique to measure the TEC and then correct the range data; (2) that space agencies use the highest available frequency band for transmitting the single frequency uplink. CCSDS 401 (3.4.3A) B-1 Page 3.4.3A-1 May 1992 3.4.3A OPTIMAL CHARGED PARTICLE CALIBRATION TECHNIQUES FOR RANGING DATA UNDER VARIOUS PROPAGATION CONDITIONS, SINGLE STATION TRACKING, CATEGORY A (Continued) ANNEX TO RECOMMENDATION [IMAGE] 6445-445ab FIGURE 3.4.3A-1: RANGING ACCURACY VERSUS RMS EQUIPMENT UNCERTAINTY FOR SINGLE STATION, CATEGORY A 1 Legend [...]SF-A/S = RMS range error uncertainty in meters for single frequency, S-Band up/dual frequencies S and X down for single station Category A missions. [...]SF-A/X = RMS range error uncertainty in meters for single frequency X-Band up/dual frequency S and X down for single station Category A missions. [...]DF-A = RMS range error uncertainty in meters for dual frequency S and X up/dual frequency S and X down for single station Category A missions. NOTE: 1. See Report of the Proceedings of the Subpanel 1E Meeting at the Ames Research Center, "Optimal Charged-Particle Calibration Technique for Ranging Data Channel", p 215, September 1989. CCSDS 401 (3.4.3A) B-1 Page 3.4.3A-2 May 1992 3.5.1 MINIMUM SET OF SPACECRAFT - EARTH STATION TESTS REQUIRED TO ENSURE COMPATIBILITY The CCSDS, considering (a) that cross support will frequently be required for Telemetry, Tracking, and/or Command operation; (b) that it is desirable to assure compatibility of the spacecraft with the ground network before the launch of a spacecraft; (c) that this compatibility is usually verified by compatibility tests; (d) that all parties have a common understanding of the tests; recommends that, in accordance with the required cross support, all relevant tests set forth in Table 3.5.1-1 shall be performed. CCSDS 401 (3.5.1) B-1 Page 3.5.1-1 September 1989 3.5.1 MINIMUM SET OF SPACECRAFT - EARTH STATION TESTS REQUIRED TO ENSURE COMPATIBILITY (Continued) TABLE 3.5.1-1 | | | TEST TYPES 1 | | | | SPACECRAFT RADIO FREQUENCY | | | | Transmitter frequency and frequency stability | | Transmitter residual carrier phase jitter | | Transmitter RF spectrum measurement | | Receiver rest frequency determination | | Receiver acquisition frequency range and rate | | Receiver tracking frequency range and rate | | | | TELEMETRY | | | | Telemetry modulation index | | Telemetry receiver carrier threshold | | Telemetry bit error rate | | Telemetry spectrum | | | | TELECOMMAND | | | | S/C receiver command and carrier threshold | | S/C receiver telecommand phase modulation index variation | | Telecommand receiver spurious carrier immunity | | Telecommand receiver spurious modulation immunity | | | | RANGING | | | | Transponder ranging delay | | Ranging downlink modulation index vs. uplink modulation index | | Ranging downlink spectrum | | Ranging downlink modulation index vs. uplink signal-to-noise power | | | | EARTH STATION ANTENNA TRACKING SYSTEM | | | | Receiver carrier signal level threshold | | | NOTE: 1. See CCSDS Radio Frequency and Modulation Systems, Spacecraft-Earth Station Compatibility Test Procedures, CCSDS 412.0 G-1, May 1992, for descriptions of the test procedures and equipment. CCSDS 401 (3.5.1) B-1 Page 3.5.1-2 September 1989 3.6.1A REDUCTION IN INTERFERENCE FROM SPACE-TO-SPACE LINKS TO OTHER SPACE SERVICES IN THE 2025 - 2110 and 2200 - 2290 MHz BANDS, CATEGORY A The CCSDS, considering (a) that, in accordance with provisions 747 and 750 of the ITU Radio Regulations, space-to-space links shall not cause harmful interference to other space systems; (b) that the planned increase in the number of space-to-space links will nevertheless raise the likelihood of harmful interference; (c) that channel coding techniques, such as concatenated codes, can reduce the power spectral density by more than 10 dB; (d) that spectrum spreading techniques can also be used to reduce the power spectral density; recommends that the power spectral density of space-to-space links be reduced by using appropriate techniques, such as concatenated codes (see CCSDS Recommendation 101.0 B-2) and/or spectrum spreading, in order to reduce the potential for harmful interference to space-to-earth and earth-to-space links. CCSDS 401 (3.6.1A) B-1 Page 3.6.1A-1 September 1989 4.0 PROCEDURAL RECOMMENDATIONS As telecommunications systems become more sophisticated, it is imperative that aids be developed to assist in the design, performance evaluation, and perhaps even validation of these systems. Early on, the CCSDS was only concerned with technical Recommendations which promoted a uniformity in data systems. However, Subpanel 1E soon discovered that efficient use of the radio frequency spectrum was an imperative. Such efficient use implies constraints, and the first Blue Book included a Policy section. This section contained many Recommendations limiting CCSDS Agencies' use of radio frequencies beyond those already imposed by the ITU's Radio Regulations. However, efficient use also implies optimal designs. The more efficiently a communications link can be made to operate, the more the frequency spectrum can be shared with other users. Use of the radio frequency bands is increasing so rapidly that sharing has become essential. This section contains procedural Recommendations intended to assist the CCSDS Agencies to efficiently design and operate their telecommunications links. These Recommendations are, in effect, tools to optimize the design and performance of those links. Presently, Recommendations in this section will be found in two categories. 4.1 Design Tools 4.2 Computational Algorithms However, it is likely that future Recommendations will also cover such areas as performance evaluation and validation. Many of these tools can be most efficiently applied if they are in the form of computer programs. Work is underway to develop such programs for several Recommendations. These programs are being designed to run on small personal computers of the IBM AT class. Periodically, readers may wish to contact either the CCSDS Secretariat, or CCSDS Subpanel 1E members, to ascertain what programs are available. CCSDS 401 B Page 4.0-1 June 1993 DESIGN TOOLS RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 4.1.1 Mod Index Procedure for optimizing. Determination 4.1.2 Link Design Control Standard form for information Table exchange. 4.1.3 Terminology Definitions of terms found in DCT. 4.1.4 Probability Density Default values for link performance Functions computation. 4.1.5 PC/PT, PD/PT, PR/PT Modulation loss equations used in CCSDS DCT. 4.1.6 Reserved for DCT 4.1.7 Reserved for DCT CCSDS 401 (4.0) B Page 4.0-2 November 1994 COMPUTATIONAL ALGORITHMS RECOMMENDATION SUMMARY REC. RECOMMENDED RECOMMENDATION SUMMARY NO. CHARACTERISTICS 4.2.1 Occupied Bandwidth Approximations for calculating. PCM/PM CCSDS 401 (4.0) B Page 4.0-3 November 1994 4.1.1 SELECTION OF OPTIMUM MODULATION INDICES FOR SIMULTANEOUS RANGING, TELECOMMAND, AND TELEMETRY OPERATIONS The CCSDS, considering (a) that two-way transmissions are generally employed for making range measurements to a distant spacecraft; (b) that, for simultaneous telecommand and ranging on the earth-to- space link, the telecommand performance may suffer some degradation due to telecommand-ranging cross-modulation components; (c) that, for simultaneous telemetry and ranging on the space-to-earth link, the telemetry performance may be degraded due to interference from the filtered versions of the uplink ranging, feed-through telecommand, cross-modulation components and noise; (d) that the timing offset due to asynchronous clocks between the telecommand and telemetry may cause serious telemetry bit error rate (BER) degradation when the two subcarriers are not separated in frequency sufficiently; (e) that the performance degradation in the telecommand and telemetry due to the factors named in considerations in (b), (c) and (d) can be minimized if the modulation indices for telecommand, range, telemetry are chosen properly; (f) that the ranging receiver is usually not susceptible to interference from unwanted emissions which fall outside the receiver's bandwidth; (g) that the selected modulation indices will provide the optimum power division between the data (telecommand/telemetry) and the ranging channels for a required ranging accuracy, and a specified bit error rate degradation in the data channel; (h) that the selected modulation indices will result in adequate power for carrier tracking without degrading the specified data channel performance; (i) that the selected modulation indices will provide the required link performance margins for the carrier, range and data signals; recommends that the CCSDS agencies utilize the technique illustrated in Annex 1 and Figure 4.1.1-1 to select the optimum set of modulation indices for simultaneous ranging, telecommand, and telemetry operations; CCSDS 401 (4.1.1) B-1 Page 4.1.1-1 September 1989 4.1.1 SELECTION OF OPTIMUM MODULATION INDICES FOR SIMULTANEOUS RANGING, TELECOMMAND, AND TELEMETRY OPERATIONS (Continued) ANNEX 1 The constants A1, A2, A3, A4, A5, and the design factor K shown in Figure 4.1.1-1 are defined as follows: (SNR)D A1 = ŽŽŽŽŽŽ (SNR)C (SNR)D A2 = ŽŽŽŽŽŽ (SNR)R (SNR)R 1 A3 = ŽŽŽŽŽŽ = ŽŽŽ (SNR)D A2 A4 = (SNR)R {[...]D(dB)/10} A5 (dB) = 10 log10 [10 - 1] U ¨ U ¨ 3 (SNR)R 3 3 1 3 k = 3 ŽŽŽŽŽŽŽ 3 x 3 ŽŽŽ 3 3 (SNR)D 3 3 [...]S 3 A U A U where: [...]D (dB) = Degradation in the Data Channel due to the interference from the ranging channel. [...]s (dB) = A5 (dB) - [(SNR)REQ + PI (dB)] (SNR)REQ = Required data signal-to-noise ratio to achieved a desired bit error rate. PI = The maximum ranging channel power level which falls into the data channel. (SNR)D = Threshold signal-to-noise power density ratio in the data channel. (SNR)C = Threshold signal-to-noise power density ratio in the carrier channel. (SNR)R = Threshold signal-to-noise power density in the ranging channel. CCSDS 401 (4.1.1) B-1 Page 4.1.1-2 September 1989 4.1.1 SELECTION OF OPTIMUM MODULATION INDICES FOR SIMULTANEOUS RANGING, TELECOMMAND, AND TELEMETRY OPERATIONS (Continued) [IMAGE] 6485-23012An FIGURE 4.1.1-1 MT's ALGORITHM: AN ALGORITHM TO SEARCH FOR A SET OF OPTIMUM MODULATION INDICES FOR SIMULTANEOUS COMMAND / TELEMETRY / RANGE OPERATIONS CCSDS 401 (4.1.1) B-1 Page 4.1.1-3 September 1989 4.1.1 SELECTION OF OPTIMUM MODULATION INDICES FOR SIMULTANEOUS RANGING, TELECOMMAND, AND TELEMETRY OPERATIONS (Continued) [IMAGE] LEGEND: (Eb/No) (dB) = REQUIRED BIT SNR TO ACHIEVE A DESIRED BER IN dB 2 BLO(dB-Hz) = TWO-SIDED PLL NOISE BANDWIDTH IN dB- Hz (SNR)2 BLO (dB) = REQUIRED OPERATING THRESHOLD IN dB BR(dB-Hz) = REQUIRED DATA BIT RATE IN dB-Hz (SNR) D (dB) = SNR DEGRADATION DUE TO RECEIVER HARDWARE IN dB BWR(dB-Hz) = RANGING BANDWIDTH IN dB-Hz (2-SIDED) (SNR) BW (dB) = REQUIRED RANGING SNR BWR, EXPRESSED IN dB (SNR) R (dB) = SNR DEGRADATION DUE TO RANGING RECEIVER HARDWARE IN dB S = RANGING SUPPRESSION RELATIVE TO DATA POWER LEVEL IN dB K = DESIGN FACTOR D(dB) = DEGRADATION IN THE DATA CHANNEL DUE TO THE INTERFERENCE FROM THE RANGING CHANNEL mD = DATA CHANNEL MODULATION INDEX IN RADIAN mR = RANGING CHANNEL MODULATION INDEX IN RADIAN PD = THE RECOVERABLE POWER IN THE FIRST-ORDER SIDEBAND OF THE DATA CHANNEL PR = THE RECOVERABLE POWER IN THE FIRST-ORDER SIDEBAND OF THE RANGING CHANNEL PT = TOTAL TRANSMITTED POWER PC = THE RECOVERABLE POWER IN THE CARRIER CHANNEL CMC = CALCULATED CARRIER PERFORMANCE MARGIN DMC = CALCULATED DATA PERFORMANCE MARGIN RMC = CALCULATED RANGING MARGIN CMREQ = REQUIRED CARRIER PERFORMANCE MARGIN DMREQ = REQUIRED DATA PERFORMANCE MARGIN RMREQ = REQUIRED RANGING PERFORMANCE MARGIN FIGURE 4.1.1-1 MT's ALGORITHM: AN ALGORITHM TO SEARCH FOR A SET OF OPTIMUM MODULATION INDICES FOR SIMULTANEOUS COMMAND / TELEMETRY / RANGE OPERATIONS 6485-23012Bn CCSDS 401 (4.1.1) B-1 Page 4.1.1-4 September 1989 4.1.1 SELECTION OF OPTIMUM MODULATION INDICES FOR SIMULTANEOUS RANGING, TELECOMMAND, AND TELEMETRY OPERATIONS (Continued) [IMAGE] FIGURE 4.1.1-1 MT's ALGORITHM: AN ALGORITHM TO SEARCH FOR A SET OF OPTIMUM MODULATION INDICES FOR SIMULTANEOUS COMMAND / TELEMETRY / RANGE OPERATIONS 6485-23012Cn CCSDS 401 (4.1.1) B-1 Page 4.1.1-5 September 1989 4.1.1 SELECTION OF OPTIMUM MODULATION INDICES FOR SIMULTANEOUS RANGING, TELECOMMAND, AND TELEMETRY OPERATIONS (Continued) [IMAGE] 6485-23012Dn FIGURE 4.1.1-1 MT's ALGORITHM: AN ALGORITHM TO SEARCH FOR A SET OF OPTIMUM MODULATION INDICES FOR SIMULTANEOUS COMMAND / TELEMETRY / RANGE OPERATIONS CCSDS 401 (4.1.1) B-1 Page 4.1.1-6 September 1989 4.1.2 TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE (Link and Weather Not Combined) The CCSDS, considering (a) that an ability to exchange telecommunications link performance information is necessary for agencies to engage in cooperative space missions, conduct joint space ventures, and provide ground station cross support to another agency's spacecraft; (b) that a uniform method for presenting link parameters and calculating link performance will facilitate the exchange of information; (c) that a uniform Design Control Table (DCT) is a convenient method for displaying telecommunications link performance information; (d) that the order in which the parameters are arranged in the Design Control Table can affect its clarity and the ease with which a signal can be traced through a telecommunications system; (e) that nominal link parameter values, representing the expected performance by the link, are important to an understanding of the telecommunications system; (f) that favorable and adverse tolerances on the nominal link parameter values are required to provide confidence in the link's performance; recommends (1) that the uniform Design Control Table, consisting of the general information and link performance pages contained in the Annex, be used as a means for comparing telecommunications link performance calculations between agencies; (2) that in computing favorable and adverse tolerances on the nominal performance values, agencies should use 3-sigma values for the telecommand system and use 2-sigma values for all other systems. CCSDS 401 (4.1.2) B-1 Page 4.1.2-1 September 1989 4.1.2 ANNEX - TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE CCSDS LINK DESIGN CONTROL TABLE GENERAL INFORMATION (Link and Weather Not Combined) Page 1 1 Owner CCSDS Agency 2 Name of Mission 3 Name of Spacecraft 4 Mission Category a. A = Alt.<2,000,000 km b. B = Alt.>2,000,000 km 5 Link Budget Number 6 Revision No. / Conditions 7 Date 8 File Name Project Name: Cognizant PersonTitl e: Address: 9 Telephone No: Fax No: E-Mail No: Network Name: Cognizant PersonAddr ess: 10 Telephone No: FAX No: E-Mail No: CCSDS 401 (2.1.2) B-1 Page 4.1.2-3 September 1989 4.1.2 ANNEX (Cont.) - TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE CCSDS LINK DESIGN CONTROL TABLE COMMUNICATIONS SYSTEM OPERATING CONDITIONS (Link and Weather Not Combined) Page 2 EARTH - SPACE - LINK SPACE - EARTH - LINK E/S TRANSMITTING RF CHANNEL: S/C TRANSMITTING RF CHANNEL: 1 RF Carrier Modulation 11 RF Carrier Modulation a. Ch 1 Type a. Ch 1 Type b. Ch 1 Format b. Ch 1 Format c. Ch 2 Type c. Ch 2 Type d. Ch 2 Format d. Ch 2 Format E/S TRANSMITTING DATA S/C TRANSMITTING DATA CHANNEL: CHANNEL: 2 Baseband Data 12 Baseband Data a. Ch 1 Bit a. Ch 1 Bit Rate, b/s Rate, kb/s b. Ch 1 Bit b. Ch 1 Bit Error Rate Error Rate c. Ch 2 Bit c. Ch 2 Bit Rate, b/s Rate, kb/s d. Ch 2 Bit d. Ch 2 Bit Error Rate Error Rate 3 Data Coding 13 Data Coding a. Ch 1 Type a. Ch 1 Rate b. Ch 1 No. b. Ch 1 Info Bits Constraint Length c. Ch 1 Block c. Ch 1 Length Concatenated Code d. Ch 1 Data/Total Bits d. Ch 2 Type e. Ch 2 Rate e. Ch 2 No. f. Ch 2 Info Bits Constraint Length f. Ch 2 Block g. Ch 2 Length Concatenated Code h. Ch 2 Data/Total Bits 4 Subcarrier 14 Subcarrier a. Ch 1 a. Ch 1 Waveform Waveform b. Ch 1 b. Ch 1 Frequency Frequency c. Ch 1 Mod c. Ch 1 Type Modulation Type d. Ch 2 d. Ch 2 Waveform Waveform e. Ch 2 e. Ch 2 Frequency Frequency f. Ch 2 Mod f. Ch 2 Type Modulation Type E/S TRANSMITTING RNG CHANNEL: S/C - E/S RNG CHANNEL: 5 a. System Type 15 a. Code Regeneration b. Tone/Code b. Coherent Wavfrm Ops Reqd c. Highest c. Required Frequency Accuracy (m) d. Lowest d. Bandwidth Frequency T/C 1 (Hz) e. Total Comp e. Bandwidth No. T/C 2 (Hz) EARTH-TO-SPACE PATH SPACE-TO-EARTH PATH PERFORMANCE: PERFORMANCE: 6 a. Weather 16 a. Weather Avail (%) Avail (%) b. S/C b. S/C Distance (km) Distance (km) CCSDS 401 (2.1.2) B-1 Page 4.1.2-4 September 1989 4.1.2 ANNEX (Cont.) - TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE CCSDS LINK DESIGN CONTROL TABLE EARTH - SPACE - LINK INPUT DATA SHEET (Link and Weather Not Combined) Page 3 MISSION AND SPACECRAFT CHANNEL 1 CHANNEL 2 UNIT DESI FAV ADV DESI FAV ADV S GN TOL TOL GN TOL TOL VALU VALU E E E/S TRANSMITTING RF CARRIER CHANNEL PARAMETERS: 1 Transmitter Power dBW 2 Transmitter MHz Frequency 3 Antenna dBi Gain 4 Antenna Circuit dB Loss 5 Antenna Pointing dB Loss E/S TRANSMITTING DATA CHANNEL PARAMETERS: 6 Information Bit b/s Rate 7 Subcarrier kHz Frequency 8 Subcarrier Sin- Waveform Sq 9 RF Modulation Rad- Index pk E/S TRANSMITTING RANGING CHANNEL PARAMETERS: 10 Simultaneous With Yes- Data No 11 Ranging Waveform Sin- Sq 12 a. Mod Index Rad- Tone/Code 1 pk b. Mod Index Rad- Tone/Code 2 pk EARTH - TO - SPACE PATH PARAMETERS: 13 Topocentric Range km 14 Atmospheric dB Attenuation 15 Ionospheric Loss dB 16 Antenna Elevation deg Angle S/C RECEIVING RF CARRIER CHANNEL PARAMETERS: 17 Antenna Gain dBi 18 Polarization Loss dB 19 Antenna Pointing dB Loss 20 Antenna Circuit dB Loss 21 Carrier Circuit dB Loss 22 Total Noise K Temperature a. Receiver K Operating Temp b. Feed Through K Noise c. Hot Body K Noise 23 Threshold Loop Hz Noise BW 24 Reqd Threshold dB SNR in 2 BLO S/C RECEIVING DATA CHANNEL PARAMETERS: 25 Phase Jitter Loss dB 26 Demodulator / dB Detector Loss 27 Waveform dB Distortion Loss 28 Max Rng dB Interference to Data 29 Reqd Data Eb/No dB S/C RECEIVING RNG CHANNEL PARAMETERS: 30 Ranging dB Demodulator Loss 31 Ranging Filter MHz Bandwidth 32 Required dB Tone/Code 1 SNR 33 Required dB Tone/Code 2 SNR CCSDS 401 (2.1.2) B-1 Page 4.1.2-5 September 1989 4.1.2 ANNEX (Cont.) - TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE CCSDS LINK DESIGN CONTROL TABLE SPACE - EARTH - LINK INPUT DATA SHEET (Link and Weather Not Combined) Page 4 MISSION AND SPACECRAFT CHANNEL 1 CHANNEL 2 UNITS DESIG FAV ADV DESIG FAV ADV N TOL TOL N TOL TOL VALUE VALUE S/C TRANSMITTING RF CARRIER CHANNEL PARAMETERS: 51 Transmitter dBW Power 52 Transmitter MHz Frequency 53 Antenna Gain dBi 54 Antenna Circuit dB Loss 55 Antenna Pointing dB Loss S/C TRANSMITTING DATA CHANNEL PARAMETERS: 56 Information Bit kb/s Rate 57 Subcarrier kHz Frequency 58 Subcarrier Sin- Waveform Sq 59 RF Modulation Rad- Index pk S/C TRANSMITTING RNG CHANNEL PARAMETERS: 60 Simultaneous Yes- With Data No 61 Mod Index Rad- Tone/Code pk SPACE - TO - EARTH PATH PARAMETERS: 62 Topocentric km Range 63 Atmospheric dB Attenuation 64 Ionospheric Loss dB 65 Antenna deg Elevation Angle E/S RECEIVING RF CARRIER CHANNEL PARAMETERS: 66 Ant dBi Gain 67 Polarization Loss dB 68 Antenna Pointing dB Loss 69 Antenna Circuit dB Loss 70 Total Noise K Temperature a. Receiver K Operating Temp b. Feed Through K Noise c. Hot Body K Noise d. Weather Temp K Increase 71 Threshold Loop Hz Noise BW 72 Reqd Threshold dB SNR in 2 BLO E/S RECEIVING DATA CHANNEL PARAMETERS: 73 Phase Jitter Loss dB 74 Demodulator / dB Detector Loss 75 Waveform dB Distortion Loss 76 Max Rng dB Interference to Data 77 Required Data dB Eb/No E/S RECEIVING RNG CHANNEL PARAMETERS: 78 Ranging dB Demodulator Loss 79 Required dB-Hz Tone/Code 1 Pwr/No 80 Required dB-Hz Tone/Code 2 Pwr/No CCSDS 401 (2.1.2) B-1 Page 4.1.2-6 September 1989 4.1.2 ANNEX (Cont.) - TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE CCSDS LINK DESIGN CONTROL TABLE EARTH - TO - SPACE LINK LINK COMPUTATIONS (Link and Weather Not Combined) Page 5 MISSION AND SPACECRAFT UNITS DESIG MEAN VARI- PDF REMARKS N VALUE ANCE REF VALUE E/S TRANSMITTING RF CARRIER CHANNEL PERFORMANCE: 101 Transmitter Power dBW TRI 102 Transmit Antenna dB UNI Gain [Effect] 103 Transmit EIRP dBW TRI 104 Transmit Carrier dBW TRI Power 105 Transmit Carrier dB TRI Power/PT E/S TRANSMITTING DATA CHANNEL PERFORMANCE: 106 Transmit Ch 1 dBW TRI Data Power 107 Transmit Ch 1 dB TRI Data Power/PT 108 Transmit Ch 2 dBW TRI Data Power 109 Transmit Ch 2 dB TRI Data Power/PT E/S TRANSMITTING RNG CHANNEL PERFORMANCE: 110 Tone - Code 1 dBW TRI Power 111 Tone - Code 1 dB TRI Power/PT 112 Tone - Code 2 dBW TRI Power 113 Tone - Code 2 dB TRI Power/PT EARTH - TO - SPACE PATH PERFORMANCE: 114 Free Space Loss dB TRI 115 Atmospheric dB GAU Attenuation 116 Ionospheric Loss dB GAU S/C RECEIVING RF CARRIER CHANNEL PERFORMANCE: 117 Receiving Antenna dBi UNI Gain [Effect] 118 Noise Spectral dBW/H GAU Density z 119 Threshold Loop Hz TRI BW, 2 BLO 120 Received Carrier dBW TRI Power 121 Carrier dB TRI Performance Margin S/C RECEIVING DATA CHANNEL PERFORMANCE: 122 Ch 1 Data Loss dB TRI Due to Rng 123 Received Ch 1 Eb dB TRI / No 124 Required Ch 1 Eb dB / No 125 Ch 1 Data dB TRI Performance Margin 126 Ch 2 Data Loss dB TRI Due to Rng 127 Received Ch 2 Eb dB TRI / No 128 Required Ch 2 Eb dB / No 129 Ch 2 Data dB TRI Performance Margin S/C RECEIVING RNG CHANNEL PERFORMANCE: 130 Received Code 1 dB-Hz TRI Power / No 131 Received Code 2 dB-Hz TRI Power / No 132 Received Total dB-Hz TRI Rng Power / No 133 Ranging Margin dB TRI CCSDS 401 (2.1.2) B-1 Page 4.1.2-7 September 1989 4.1.2 ANNEX (Cont.) - TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE CCSDS LINK DESIGN CONTROL TABLE SPACE - TO - EARTH LINK LINK COMPUTATIONS (Link and Weather Not Combined) Page 6 MISSION AND SPACECRAFT UNITS DESIG MEAN VARI- PDF REMARKS N VALUE ANCE REF VALUE S/C TRANSMITTING RF CARRIER CHANNEL PERFORMANCE: 151 Transmitter Power dBW TRI 152 Transmit Antenna dB UNI Gain [Effect] 153 Transmit EIRP dBW TRI 154 Transmit Carrier dBW TRI Power 155 Transmit Carrier dB TRI Power/PT S/C TRANSMITTING DATA CHANNEL PERFORMANCE: 156 Transmit Ch 1 dBW TRI Data Power 157 Transmit Ch 1 dB TRI Data Power/PT 158 Transmit Ch 2 dBW TRI Data Power 159 Transmit Ch 2 dB TRI Data Power/PT S/C TRANSMITTING RNG CHANNEL PERFORMANCE: 160 Tone - Code 1 dBW TRI Power 161 Tone - Code 1 dB TRI Power/PT 162 Tone - Code 2 dBW TRI Power 163 Tone - Code 2 dB TRI Power/PT SPACE - TO - EARTH PATH PERFORMANCE: 164 Free Space Loss dB TRI 165 Atmospheric dB GAU Attenuation 166 Ionospheric Loss dB GAU E/S RECEIVING RF CARRIER CHANNEL PERFORMANCE: 167 Receiving Antenna dBi UNI Gain [Effect] 168 Noise Spectral dBW/H GAU Density z 169 Threshold Loop Hz TRI BW, 2 BLO 170 Received Carrier dBW TRI Power 171 Carrier dB GAU Performance Margin E/S STATION RECEIVING DATA CHANNEL PERFORMANCE: 172 Ch 1 Data Loss dB TRI Due to Rng 173 Received Ch 1 Eb dB TRI / No 174 Required Ch 1 Eb dB / No 175 Ch 1 Data dB GAU Performance Margin 176 Ch 2 Data Loss dB TRI Due to Rng 177 Received Ch 2 Eb dB TRI / No 178 Required Ch 2 Eb dB / No 179 Ch 2 Data dB GAU Performance Margin E/S STATION RECEIVING RNG CHANNEL PERFORMANCE: 180 Received Code 1 dB-Hz TRI Power / No 181 Received Code 2 dB-Hz TRI Power / No 182 Received Total dB-Hz TRI Rng Power / No 183 Ranging dB GAU Performance Margin CCSDS 401 (2.1.2) B-1 Page 4.1.2-8 September 1989 4.1.2 ANNEX (Cont.) - TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE CCSDS LINK DESIGN CONTROL TABLE EXPLANATION OF REMARKS (Link and Weather Not Combined) Page 7 UPLINK 1 Design value of the Transmitted Carrier Power (dBW) is computed using the design value of Pc/Pt and the EIRP. The design value of Pc/Pt is computed by using the design values of the several modulation indices. 2 Mean Transmitted Carrier Power (dBW) is computed by examining all combinations of favorable and adverse tolerances for the several modulation indices, selecting the best and worst cases, and computing Pc/Pt and EIRP. The variance on Transmitted Carrier Power (dBW) is computed by using the EIRP with the favorable and adverse tolerances of Pc/Pt. 2A A triangular probability density is used for Pc/Pt ratio. 3 Design value of the Transmitted Data Power (dBW) is computed using design value of Pd/Pt and of the EIRP. The design value of Pd/Pt is computed by using the design values of the several modulation indices. 4 Mean Transmitted Data Power (dBW) is computed by examining all combinations of favorable and adverse tolerances for the several modulation indices, selecting the best and worst cases, and computing Pd/Pt and EIRP. The variance on Transmitted Data Power (dBW) is computed by using the EIRP with the favorable and adverse tolerances of Pd/Pt. 4A A triangular probability density is used for the Pd/Pt ratio. 5 Design value of the Transmitted Ranging Power (dBW) is computed using the design value of Pr/Pt and of the EIRP. The design value of Pr/Pt is computed by using the design values of the several modulation indices. 6 Mean Transmitted Ranging Power (dBW) is computed by examining all combinations of favorable and adverse tolerances for the several modulation indices, selecting the best and worst cases, and computing Pr/Pt and EIRP. The variance of Transmitted Ranging Power (dBW) is computed by using the EIRP with the favorable and adverse tolerances of Pr/Pt. 6A A triangular probability density is used for the Pr/Pt ratio. 7, Space Loss: Mean and variance on the space loss are 8 computed using the favorable and adverse tolerances of the earth station - spacecraft range. 9 Atmospherics losses are assumed to be statistically independent of the link when computing margins. Mean and variance are computed using the appropriate weather model. DOWNLINK 10 Same as remark 1 but applied for the downlink. 11 Same as remark 2 but applied for the downlink. 11A Same as remark 2a but applied for the downlink. 12 Same as remark 3 but applied for the downlink. 13 Same as remark 4 but applied for the downlink. 13A Same as remark 4a but applied for the downlink. 14 Same as remark 5 but applied for the downlink. 15 Same as remark 6 but applied for the downlink. 15A Same as remark 6a but applied for the downlink. 16 Same as remark 7 but applied for the downlink. 17 Same as remark 8 but applied for the downlink. 18 Same as remark 9 but applied for the downlink. CCSDS 401 (2.1.2) B-1 Page 4.1.2-9 September 1989 4.1.2 ANNEX (Cont.) - TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE CCSDS LINK DESIGN CONTROL TABLE EXPLANATION OF REMARKS (Cont.) (Link and Weather Not Combined) Page 8 NOTES::::::: UPLINK 1.Required Tone/Code 1 SNR means the required tone / code 1 ranging power divided by the noise power in the ranging bandwidth. The user is expected to enter the value in sheet 3, line 32. 2.When the ranging margin is computed, the ranging bandwidth is used to obtain the required power-to-noise density ratio. Thereafter, this required ranging power-to-noise density ratio is subtracted from the received ranging power-to-noise density ratio to obtain the ranging margin. DOWNLINK 1.Required ranging Tone/Code Pwr/No ratio is computed automatically for DSN square wave and GSFC sidetone sinewave ranging systems. For other systems, the Required Tone/Code Pwr/No ratio must be provided by the user. The following steps should be followed. a.Specify Tone/Code integration time needed meet accuracy requirements. b.Compute effective bandwidth (e.g., 1/Integration Time). c.Using appropriate data for the ranging system in use, find required Pr/No needed to meet the specified accuracy, given the desired integration time, and enter this value on line 79. 2.Ranging margin is based on effective bandwidth computed in 1b above. CCSDS 401 (2.1.2) B-1 Page 4.1.2-8 September 1989 4.1.3 STANDARD TERMINOLOGY FOR TELECOMMUNICATIONS LINK PERFORMANCE CALCULATIONS The CCSDS, considering (a) that a uniform method for computing telecommunications link performance is desirable in order to facilitate the exchange of information among agencies; (b) that it is necessary to agree upon the definitions of certain key terms before a uniform method for computing telecommunications link performance can be adopted; (c) that definitions which have been adopted by internationally recognized organizations for such key terms should be used whenever possible; recommends (1) that the terms listed in Article 1 of the Radio Regulations and in the Annex below be used together with the meaning ascribed to them in the corresponding definition. (2) that the telecommunications link, together with the noise sources and losses, be described as shown in Figure 4.1.3-1. CCSDS 401 (4.1.3) B-1 Page 4.1.3-1 September 1989 ANNEX TO RECOMMENDATION 4.1.3 FIGURE 4.1.3-1: TYPICAL SPACE COMMUNICATIONS LINK SHOWING LOSS AND NOISE SOURCES [IMAGE] 6485-23012En CCSDS 401 (4.1.3) B-1 Page 4.1.3-2 September 1989 4.1.3 ANNEX TO RECOMMENDATION TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE (Link and Weather Not Combined): A set of informational and input data tables for the user to provide the salient earth-to-space and space-to-earth telecommunications equipment and link characteristics together with tables containing the computed performance of these links without regard to weather induced effects. GENERAL INFORMATION (1) OWNER CCSDS AGENCY: The CCSDS member agency having primary responsibility for the success or failure of the mission. (2) NAME OF MISSION: The name given to the mission by the CCSDS member agency owner. (3) NAME OF SPACECRAFT: The name given to a specific spacecraft, which is part of the named mission, by the CCSDS member agency owner. (4) MISSION CATEGORY: The mission's category, either Category B for deep space missions (missions whose altitude above the Earth's surface exceeds 2 x 10 6 km) or Category A for non-deep space missions (those whose altitude above the Earth's surface are less than, or equal to, 2 x 106 km). (5) LINK BUDGET NUMBER: A number which is assigned to this link budget study under the conditions and with the configuration stated on the following pages to distinguish it from other such studies. (6) REVISION No. / CONDITIONS: The most recent revision of this telecommunications link budget study, which is contained in this table, for the named spacecraft and mission together with a short description of the study conditions (e.g., transmitter power, station used, etc.). (7) DATE: The date that this study or revision was made. (8) FILE NAME: The name or number of the file, whether on a computer disk or other media, where this DCT is stored. (9) PROJECT COGNIZANT PERSON: Name: The name of the cognizant person in the owner agency with whom inputs to, or outputs from, this Design Control Table should be discussed and approved. Title: The cognizant person's position or title. Address: The full agency center's name and address which is required to contact the cognizant person in an efficient manner. Telephone No: The cognizant person's telephone number, including country and area code. FAX No: The cognizant person's FAX number, including country and area code. E-Mail No.: The cognizant person's full e-mail address, including any relevant node. CCSDS 401 (4.1.3) B-1 Page 4.1.3-3 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) GENERAL INFORMATION (Continued) (10) NETWORK COGNIZANT PERSON: Name: The name of the cognizant person in the agency operating the supporting network with whom inputs to, or outputs from, this Design Control Table should be discussed and approved. Address: The full network agency center's name and address which is required to contact the cognizant person in an efficient manner. Telephone No: The cognizant person's telephone number, including country and area code. FAX No: The cognizant person's FAX number, including country and area code. E-Mail No: The cognizant person's full e-mail address, including any relevant node. CCSDS 401 (4.1.3) B-1 Page 4.1.3-4 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) COMMUNICATIONS SYSTEM OPERATING CONDITIONS EARTH-TO-SPACE LINK EARTH STATION (E/S) TRANSMITTING RF CHANNEL (1) RF CARRIER MODULATION: (1a) Ch 1 Type: The earth station's carrier modulation method. Generally, only phase modulation is recommended by the CCSDS for the RF carrier. (1b) Ch 1 Format: The method used in the earth station to represent the modulated Telecommand symbols on the carrier (e.g., NRZ-L, NRZ-M, SP-L, etc.). (1c) CH 2 Type: Same definition as (1a) above except that it is applicable to RF channel 2. (1d) Ch 2 Format: Same definition as (1b) above except that it is applicable to RF channel 2. EARTH STATION (E/S) TRANSMITTING DATA CHANNEL (2) BASEBAND DATA: (2a) Ch 1 Bit Rate, b/s: The rate, usually the maximum, at which uncoded telecommand or other data on channel 1 is to be transmitted from the earth station and for which the link performance is to be evaluated, expressed in b/s. (2b) Ch 1 Bit Error Rate: The maximum information bit error rate providing acceptable performance for data channel 1 under consideration, expressed as a dimensionless fraction. (2c) Ch 2 Bit Rate, b/s: Same definition as (2a) above except that it is applicable to channel 2. (2d) Ch 2 Bit Error Rate: Same definition as (2b) above except that it is applicable to channel 2. (3) DATA CODING: (3a) Ch 1 Type: The type or name (e.g., block, Reed-Solomon, etc.) of the error detecting-correcting code used on data channel 1 by the earth station. (3b) Ch 1 No. Info Bits: The number of information bits contained in a block code on data channel 1 which is transmitted from the earth station, expressed as a number. (3c) Ch 1 Block Length: The total length of the block used on data channel 1 from the earth station, expressed as a number. (3d) Ch 2 Type: Same definition as (3a) above except that it is applicable to data channel 2. CCSDS 401 (4.1.3) B-1 Page 4.1.3-5 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) (3e) Ch 2 No. Info Bits: Same definition as (3b) above except that it is applicable to channel 2. (3f) Ch 2 Block Length: Same definition as (3c) above except that it is applicable to channel 2. (4) SUBCARRIER: (4a) Ch 1 Waveform: The earth station's subcarrier waveform on data channel 1. Sine wave subcarriers are recommended by the CCSDS for telecommand. (4b) Ch 1 Frequency: The earth station's subcarrier frequency on data channel 1, expressed in kHz. (4c) Ch 1 Mod Type: The method used by the earth station for modulating the subcarrier with the data. PSK modulation is recommended by the CCSDS for telecommand subcarriers. (4d) Ch 2 Waveform: Same definition as (4a) except that it is applicable to channel 2. (4e) Ch 2 Frequency: Same definition as (4b) above except that it is applicable to channel 2. (4f) Ch 2 Mod Type: Same definition as (4c) above except that it is applicable to channel 2. EARTH STATION (E/S) TRANSMITTING RNG CHANNEL (5a) System Type: The name, or descriptive term used to identify the specific ranging equipment (e.g., sidetone, square wave, DLR sine wave, CNES sine wave, ESA sine wave, DSN square wave, etc.). (5b) Tone/Code Wavfrm: The ranging tone or code waveform (e.g., sine or square). (5c) Highest Frequency: The highest ranging tone or code frequency to be used for this mission, expressed in kHz. (5d) Lowest Frequency: The lowest ranging tone or code frequency to be used for this mission, expressed in kHz. (5e) Total Comp No: The total number of ranging tone or code components which will be used in measuring the range, expressed as a number. EARTH-TO-SPACE PATH PERFORMANCE (6a) Weather Avail (%): The amount of time that the earth-to-space link must be available when considering the degradation due to weather, expressed as a percent. (6b) S/C Distance (km): The distance, measured along a ray path, between the earth station transmitting antenna's radiation point and the spacecraft receiving antenna's reference point, expressed in kilometers (km). CCSDS 401 (4.1.3) B-1 Page 4.1.3-6 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) COMMUNICATIONS SYSTEM OPERATING CONDITIONS (Cont.) SPACE-TO-EARTH LINK SPACECRAFT (S/C) TRANSMITTING RF CHANNEL (11) RF CARRIER MODULATION: (11a) Ch 1 Type: The spacecraft's carrier modulation method. Generally, only phase modulation is recommended by the CCSDS for the RF carrier. (11b) Ch 1 Format: The method used by the spacecraft to represent the modulated Telemetry symbols on the carrier (e.g., NRZ-L, NRZ-M, SP-L, etc.). (11c) CH 2 Type: Same definition as (11a) above except that it is applicable to RF channel 2. (11d) Ch 2 Format: Same definition as (11b) above except that it is applicable to RF channel 2. SPACECRAFT (S/C) TRANSMITTING DATA CHANNEL (12) BASEBAND DATA: (12a) Ch 1 Bit Rate, kb/s: The rate, usually the maximum, at which uncoded telemetry or other data on channel 1 is to be transmitted from the spacecraft and for which the link performance is to be evaluated, expressed in kilo b/s. (12b) Ch 1 Bit Error Rate: The maximum information bit error rate providing acceptable performance for data channel 1 under consideration, expressed as a dimensionless fraction. (12c) Ch 2 Bit Rate, kb/s: Same definition as (12a) above except that it is applicable to channel 2. (12d) Ch 2 Bit Error Rate: Same definition as (12b) above except that it is applicable to channel 2. (13) DATA CODING: (13a) Ch 1 Rate: The ratio of the number of data bits to the total number of convolutionally encoded symbols transmitted from the spacecraft, generally expressed as a fraction (e.g., 1/2 for the CCSDS recommended code). (13b) Ch 1 Constraint Length: The constraint length of the convolutional encoder on the spacecraft, expressed as a number (e.g., 7 for the CCSDS recommended code). (13c) Ch 1 Concatenated Code: The type or name of the code which is concatenated with the convolutional code on the spacecraft (e.g., Reed-Solomon, Golay, block, etc.). The CCSDS recommends Reed- Solomon. CCSDS 401 (4.1.3) B-1 Page 4.1.3-7 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) (13d) Ch 1 Data/Total Bits: The number of data bits to total bits in a spacecraft block code, expressed as a ratio (e.g., 223/255 for the CCSDS recommended Reed-Solomon code). (13e) Ch 2 Rate: Same definition as (13a) above except that it is applicable to channel 2. (13f) Ch 2 Constraint Length: Same definition as (13b) above except that it is applicable to channel 2. (13g) Ch 2 Concatenated Code: Same definition as (13c) above except that it is applicable to channel 2. (13h) Ch 2 Data/Total Bits: Same definition as (13d) above except that it is applicable to channel 2. (14) SUBCARRIER: (14a) Ch 1 Waveform: The spacecraft's subcarrier waveform on data channel 1 (e.g., sine or square). (14b) Ch 1 Frequency: The spacecraft's subcarrier frequency on data channel 1, expressed in kHz. (14c) Ch 1 Modulation Type: The spacecraft's method used for modulating the subcarrier with the data. PSK modulation is recommended by the CCSDS for telemetry subcarriers. (14d) Ch 2 Waveform: Same definition as (14a) above except that it is applicable to channel 2. (14e) Ch 2 Frequency: Same definition as (14b) above except that it is applicable to channel 2. (14f) Ch 2 Modulation Type: Same definition as (14c) above except that it is applicable to data channel 2. SPACECRAFT (S/C) - EARTH STATION (E/S) RNG CHANNEL (15a) Code Regeneration: A statement (Yes or No) indicating whether the spacecraft regenerates the ranging code prior to transmitting it to the earth station. (15b) Coherent Ops Reqd: A statement (Yes or No) indicating whether the earth station's ranging equipment requires a coherent spacecraft RF channel. (15c) Required Accuracy (m): The required ranging measurement accuracy, expressed in meters. (15d) Bandwidth T/C 1 (Hz): The earth station's effective bandwidth (1/integration time) required to obtain the ranging measurement accuracy stated in 5c, above, with the Pr/N0 stated on the Input Data Sheet, expressed in Hz. (15e) Bandwidth T/C 2 (Hz): The earth station's effective bandwidth (1/integration time) required to obtain the required probability of success in the ranging measurement, expressed in Hz. CCSDS 401 (4.1.3) B-1 Page 4.1.3-8 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) SPACE-TO-EARTH PATH PERFORMANCE (16a) Weather Avail (%): The amount of time that the space-to-earth link must be available when considering the degradation due to weather, expressed as a percent. (16b) S/C Distance (km): The distance, measured along a ray path, between the spacecraft transmitting antenna's radiation point and the earth station receiving antenna's reference point, expressed in kilometers (km). CCSDS 401 (4.1.3) B-1 Page 4.1.3-9 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) INPUT DATA SHEET FOR EARTH-TO-SPACE LINK EARTH STATION (E/S) TRANSMITTING RF CARRIER CHANNEL PARAMETERS (1) TRANSMITTER POWER: That power actually produced at the transmitter power amplifier's output terminals, expressed as a positive or negative value in dBW (10 Log10 [Watts]). (2) TRANSMITTER FREQUENCY: The unmodulated transmitter carrier frequency, expressed in Megahertz (MHz). (3) ANTENNA GAIN (ITU/RR/154): "The ratio, usually expressed in decibels, of the power required at the input of a loss-free reference antenna to the power supplied to the input of the given antenna to produce, in a given direction, the same field strength or power flux-density at the same distance. When not specified otherwise, the gain refers to the direction of maximum radiation." In this application, the reference antenna is an isotropic antenna located in free space. The antenna's gain is expressed as a positive or negative value in dBi. Placing the network's name (e.g., DSN) in the box to the right of Antenna Gain and the antenna's diameter (e.g., 70) in box to the right of the network in row 3 will cause the computer program to consult its data base for all required information regarding that station. (4) ANTENNA CIRCUIT LOSS: The attenuation in rf power occurring between the output terminals of the transmitting power amplifier and the point of electromagnetic radiation from that antenna, expressed as a negative value in dB. (5) ANTENNA POINTING LOSS: The reduction in signal power at the receiving antenna resulting from imperfect pointing of the transmitting antenna such that the actual ray path from transmitting antenna to receiving antenna differs from the optimum ray path containing the point of maximum transmitting antenna gain, expressed as a negative value in dB. EARTH STATION (E/S) TRANSMITTING DATA CHANNEL PARAMETERS (6) INFORMATION BIT RATE: The rate at which uncoded Telecommand information bits are to be sent from the transmitting station to the receiving station, expressed in bits per second (b/s). (7) SUBCARRIER FREQUENCY: The unmodulated Telecommand subcarrier's frequency, either 8 kHz or 16 kHz, expressed in kHz. (8) SUBCARRIER WAVEFORM: The Telecommand subcarrier's waveform is always sine wave. (9) RF MODULATION INDEX: The angle by which the rf carrier is phase shifted, with respect to the unmodulated rf carrier, as a result of the data on Telecommand channel of the modulator, expressed in radians peak. CCSDS 401 (4.1.3) B-1 Page 4.1.3-10 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) EARTH STATION (E/S) TRANSMITTING RANGING CHANNEL PARAMETERS (10) SIMULTANEOUS WITH DATA: A statement showing whether the computed performance is based upon simultaneous ranging and telecommanding operations ( e.g., Yes or No). (11) RANGING WAVEFORM: The waveform of the ranging modulation, sine wave for tone modulation, square wave for code modulation, expressed as Sin or Sq. (12a) MOD INDEX TONE / CODE 1: The angle by which the rf carrier is phase shifted, with respect to the unmodulated rf carrier, as a result of the highest frequency (major) ranging Tone / Code modulation, expressed in radians peak (Rad-pk). (12b) MOD INDEX TONE / CODE 2: The angle by which the rf carrier is phase shifted, with respect to the unmodulated rf carrier, as a result of the lower frequency (minor) ranging Tones / Codes modulation, expressed in radians peak (Rad-pk). EARTH-TO-SPACE PATH PARAMETERS (13) TOPOCENTRIC RANGE: The distance, measured along a ray path, between the earth station transmitting antenna's radiation point and the spacecraft receiving antenna's reference point, expressed in kilometers (km). (14) ATMOSPHERIC ATTENUATION: The reduction in signal power at the receiving antenna, considering such factors as the earth station's antenna elevation angle, weather, and geographical location, which results from absorption, reflection, and scattering of the rf signal as it passes through the Earth's atmosphere, expressed as a negative value in dB. (15) IONOSPHERIC LOSS: The reduction in signal power at the receiving antenna, considering such factors as the earth station's elevation angle and communication's frequency, resulting from the dispersive loss in radiated signal as it passes through the Ionosphere of the Earth and/or other bodies, expressed as a negative value in dB. (16) ANTENNA ELEVATION ANGLE: The angle between a ray, representing the boresight of the earth-station's antenna beam pattern, and a locally horizontal line, when both ray and line are contained in a vertical plane which also contains the center of the earth, expressed in degrees (deg). SPACECRAFT (S/C) RECEIVING CARRIER RF CHANNEL PARAMETERS (17) ANTENNA GAIN: The ratio of the power flux density required at the input of a loss-free isotropic antenna to that power flux density needed at the input of the spacecraft's receiving antenna which produces the same output at the antenna's terminals for a source which is at equal distance from both antennas. The gain of the spacecraft's receiving antenna refers to the direction of maximum sensitivity, except in the case of a non-directional antenna in which case the gain refers to a minimum value corresponding to the antenna's specified coverage. The gain of the subject antenna, at the receiving frequency, is expressed as a positive or negative value in dBi. CCSDS 401 (4.1.3) B-1 Page 4.1.3-11 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) (18) POLARIZATION LOSS: The reduction in transferred signal power between transmitting and receiving stations resulting from differences in the radiated and received polarization patterns between the two antennas, expressed as a negative value in dB. (19) ANTENNA POINTING LOSS: Same definition as (5) above except that it is applicable to the pointing error of the spacecraft's receiving antenna, expressed as a negative value in dB. (20) ANTENNA CIRCUIT LOSS: The attenuation in rf power occurring between the point of electromagnetic radiation on the spacecraft's antenna and the input terminals of the low noise amplifier, expressed as a negative value in dB. (21) CARRIER CIRCUIT LOSS: The sum of resistive (cable and circuitry), transmission line mismatches, and other implementation losses, expressed as a negative value in dB. (22) TOTAL NOISE TEMPERATURE: The sum of the following noise temperature components (a) +(b) + (c). expressed in dBK. This sum is a computed entry and is not supplied by the user. (a) Receiver Operating Temp: Overall Noise Temperature (CCIR/Rec 573-1): "For an antenna, or a receiving system including the antenna, the value to which the temperature of the resistive component of the source impedance should be brought, if it were the only source of noise, to cause the noise power at the output of the receiver to be the same as in real case." In the Link Design Control Table, this parameter represents a receiving system reference temperature, at the received frequency, which excludes all contributions enumerated in (b), and (c), below, expressed in Kelvin. The reference temperature is measured at the input to the low- noise amplifier with the antenna viewing a cold sky background and which includes contributions from the: 1) cosmic background; 2) low noise amplifier and/or receiver; 3) circuit losses before the low-noise amplifier and/or receiver. (b) Feed Through Noise: The increase in the receiver's operating temperature resulting from a portion of the transmitted signal leaking into the receiver's low-noise amplifier, expressed in Kelvin (K). (c) Hot Body Noise: The predicted increase from the reference temperature (Tr), resulting from the receiving antenna being directed toward a body having a temperature greater than that of the cold sky reference, expressed in Kelvin (K). (23) THRESHOLD LOOP NOISE BW: The total (2-sided) bandwidth of the rf carrier's phase-locked-loop, measured at the point when the SNR in that phase-locked-loop is +10 dB (carrier threshold), expressed in Hz. (24) REQD THRESHOLD SNR IN 2 BLO : The ratio of received carrier power in 2 BLO to the noise power density required to maintain receiver lock at threshold which has been defined to be +10 dB, expressed as a positive or negative value in dB. CCSDS 401 (4.1.3) B-1 Page 4.1.3-12 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) SPACECRAFT (S/C) RECEIVING DATA CHANNEL PARAMETERS (25) PHASE JITTER LOSS: The loss in symbol detection efficiency resulting from phase noise on the received rf carrier, which produces a non-orthogonal, noisy phase relationship between the demodulator's reference and the rf carrier to be demodulated, plus losses from the partial tracking of the modulated symbols by the rf carrier phase locked loop, expressed as a negative value in dB. (26) DEMODULATOR / DETECTOR LOSS: The loss in data demodulation and detection efficiency resulting from phase noise on the demodulated subcarrier, which produces a non-orthogonal, noisy phase relationship between the demodulator's reference and the subcarrier to be demodulated, plus losses from the partial tracking of the data bits by the subcarrier loop, plus losses due to timing errors in the symbol synchronizer's tracking loop, plus losses from non- linearities in the demodulator, which reduce the device's efficiency, expressed as a negative value in dB. (27) WAVEFORM DISTORTION LOSS: The loss in the recovered data signal power resulting from distortion in the modulated signal's (subcarrier and data) waveform, which has been introduced by filtering and non-linearities in the data channel or medium, expressed as a negative value in dB. (28) MAX RNG INTERFERENCE TO DATA: The ratio of the ranging modulation's maximum spectral power level, lying within the data spectrum bandwidth [data spectrum bandwidth equals the data symbol rate in Hz], to the total ranging power level, expressed as a negative value in dB. (29) REQUIRED DATA Eb / N0 : The energy per data bit divided by the noise spectral density which is required to obtain the stated Bit Error Rate, considering the improvement due to coding, expressed in dB. SPACECRAFT (S/C) RECEIVING RANGING (RNG) CHANNEL PARAMETERS (30) RANGING DEMODULATOR LOSS: The loss in ranging demodulation and detection efficiency resulting from phase noise on the demodulated subcarrier, which produces a non-orthogonal, noisy phase relationship between the demodulator's reference and the i.f. carrier to be demodulated, plus losses from non-linearities in the demodulator, which reduce the device's efficiency, expressed as a negative value in dB. (31) RANGING FILTER BANDWIDTH: The bandwidth of the ranging channel filter in the spacecraft receiver, expressed in Megahertz (MHz). (32) REQUIRED TONE/CODE 1 SNR: The ranging tone/code 1 signal-to-noise ratio required in the spacecraft's transponder to achieve the desired ranging measurement accuracy, expressed as a positive or negative number in dB. (33) REQUIRED TONE/CODE 2 SNR: The ranging tone/code 2 signal-to-noise ratio required in the spacecraft's transponder to achieve the desired ranging ambiguity resolution, expressed as a positive or negative number in dB. CCSDS 401 (4.1.3) B-1 Page 4.1.3-13 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) INPUT DATA SHEET FOR SPACE-TO-EARTH LINK SPACECRAFT (S/C) TRANSMITTING RF CARRIER CHANNEL PARAMETERS (51) TRANSMITTER POWER: That power actually produced at the transmitter power amplifier's output terminals, expressed as a positive or negative value in dBW (10Log10 [Watts]). (52) TRANSMITTER FREQUENCY: The unmodulated transmitter carrier frequency, expressed in Megahertz. (53) ANTENNA GAIN: The ratio of the power required at the input terminals of a loss-free isotropic antenna to the power supplied to the input terminals of the spacecraft's transmitting antenna which is needed to produce, in a specified direction, the same field strength (power flux density at an equivalent distance). The gain refers to the direction of maximum radiation except for non- directional antennas, in which case, the gain refers to a minimum value corresponding to the specified antenna coverage. The gain of the subject antenna, at the transmitting frequency, is expressed as a positive or negative value in dBi. (54) ANTENNA CIRCUIT LOSS: The attenuation in rf power occurring between the output terminals of the transmitting power amplifier and the point of electromagnetic radiation from that antenna, expressed as a negative value in dB. (55) ANTENNA POINTING LOSS: The reduction in signal power at the receiving antenna resulting from imperfect pointing of the transmitting antenna such that the actual ray path from transmitting antenna to receiving antenna differs from the optimum ray path containing the point of maximum transmitting antenna gain, expressed as a negative value in dB. SPACECRAFT (S/C) TRANSMITTING DATA CHANNEL PARAMETERS (56) INFORMATION BIT RATE: The basic telemetry data rate generated by the flight data system, prior to any encoding or spectrum spreading procedures, for transmission to the receiving earth station, expressed in kilo-bits per second (kb/s). (57) SUBCARRIER FREQUENCY: The unmodulated Telemetry subcarrier's frequency, expressed as a positive value in kilo-Hertz (kHz). (58) SUBCARRIER WAVEFORM: The waveform of the Telemetry subcarrier, either sine wave or square wave, expressed as Sin or Sq. (59) RF MODULATION INDEX: The angle by which the rf carrier is phase shifted, with respect to the unmodulated rf carrier, as a result of the data on Telemetry channel of the modulator, expressed in radians peak. CCSDS 401 (4.1.3) B-1 Page 4.1.3-14 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) SPACECRAFT (S/C) TRANSMITTING RANGING (RNG) CHANNEL PARAMETERS (60) SIMULTANEOUS WITH DATA: A statement showing whether or not the computed performance is based upon simultaneous ranging and telemetry operations (e.g., Yes or No). (61) MOD INDEX TONE / CODE: The angle by which the rf carrier is phase shifted, with respect to the unmodulated rf carrier, as a result of the ranging Tones / Codes modulation, expressed in radians peak (Rad-pk). SPACE-TO-EARTH PATH PARAMETERS (62) TOPOCENTRIC RANGE: The distance, measured along a ray path, between the spacecraft antenna's radiation point and ground station antenna's reference point, expressed in kilometers (km). (63) ATMOSPHERIC ATTENUATION: The reduction in signal power at the receiving antenna, considering such factors as the earth station's antenna elevation angle, weather, and geographical location, which results from absorption, reflection, and scattering of the rf signal as it passes through the Earth's atmosphere, expressed as a negative value in dB. (64) IONOSPHERIC LOSS: The reduction in signal power at the receiving antenna, considering such factors as the earth station's elevation angle and communication's frequency, resulting from the dispersive loss in radiated signal as it passes through the Ionosphere of the Earth and/or other bodies, expressed as a negative value in dB. (65) ANTENNA ELEVATION ANGLE: The angle between a ray, representing the boresight of the earth-station's antenna beam pattern, and a locally horizontal line, when both ray and line are contained in a vertical plane which also contains the center of the earth, expressed in degrees (Deg). EARTH STATION (E/S) RECEIVING RF CARRIER CHANNEL PARAMETERS (66) ANTENNA GAIN: Same definition as (3) above except that it is applicable to the earth station's receiving frequency. See second paragraph of (3) above to access earth station data base. (67) POLARIZATION LOSS: The reduction in transferred signal power between transmitting and receiving stations resulting from differences in the radiated and received polarization patterns between the two antennas, expressed as a negative value in dB. (68) ANTENNA POINTING LOSS: Same definition as (5) above except that it is applicable to the pointing error of the earth station's receiving antenna. (69) ANTENNA CIRCUIT LOSS: The attenuation in rf power occurring between the point of electromagnetic radiation on the earth station's antenna and the input terminals of the low noise amplifier, expressed as a negative value in dB. CCSDS 401 (4.1.3) B-1 Page 4.1.3-15 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) (70) TOTAL NOISE TEMPERATURE: The sum of the following noise temperature components (a) + (b) + (c) + (d), expressed in dBK. This sum is a computed entry and is not supplied by the user. (a) Receiver Operating Temp: Overall Noise Temperature (CCIR/Rec 573-1): "For an antenna, or a receiving system including the antenna, the value to which the temperature of the resistive component of the source impedance should be brought, if it were the only source of noise, to cause the noise power at the output of the receiver to be the same as in real case." In the Link Design Control Table, this parameter represents a receiving system reference temperature, at the received frequency, which excludes all contributions enumerated in (b), and (c), below, expressed in Kelvin. The reference temperature is measured at the input to the low- noise amplifier with the antenna viewing a cold sky background and which includes contributions from the: 1) cosmic background; 2) low noise amplifier and/or receiver; 3) circuit losses before the low noise amplifier and/or receiver. (b) Feed Through Noise: The increase in the receiver's operating temperature resulting from a portion of the transmitted signal leaking into the receiver's low-noise amplifier, expressed in Kelvin (K). (c) Hot Body Noise: The predicted increase from the reference temperature (Tr), resulting from the receiving antenna being directed toward a body having a temperature greater than that of the cold sky reference, expressed in Kelvin (K). (d) Weather Temp Increase: The predicted increase from the reference temperature, resulting from the selected ground station weather model, and which excludes contributions from Atmospheric Attenuation (63), Ionospheric Loss (64), and from (b) and (c) above, expressed as a positive value in Kelvin. (71) THRESHOLD LOOP NOISE BW: The total (2-sided) bandwidth of the rf carrier phase-locked-loop, measured at carrier threshold, expressed in Hz. (72) REQD THRESHOLD SNR IN 2 BLO : The ratio of received carrier power in 2 BLO to the noise power density required to maintain receiver lock at threshold which has been defined to be +10 dB, expressed in dB. CCSDS 401 (4.1.3) B-1 Page 4.1.3-16 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) EARTH STATION (E/S) RECEIVING DATA CHANNEL PARAMETERS (73) PHASE JITTER LOSS: The loss in symbol detection efficiency resulting from phase noise on the received rf carrier, which produces a non-orthogonal, noisy phase relationship between the demodulator's reference and the rf carrier to be demodulated, plus losses from the partial tracking of the modulated symbols by the rf carrier phase locked loop, expressed as a negative value in dB. (74) DEMODULATOR / DETECTOR LOSS: The loss in data demodulation and detection efficiency resulting from phase noise on the demodulated subcarrier, if any, which produces a non-orthogonal, noisy phase relationship between the demodulator's reference and the subcarrier to be demodulated, plus losses from the partial tracking of the data bits by the subcarrier loop, plus losses due to timing errors in the symbol synchronizer's tracking loop, plus losses from non- linearities in the demodulator, which reduce the device's efficiency, expressed as a negative value in dB. (75) WAVEFORM DISTORTION LOSS: The loss in the recovered data signal power, which results from distortion in the modulated signal's (subcarrier and data) waveform, which has been introduced by non- linearities in the data channel or medium, expressed as a negative value in dB. (76) MAX RNG INTERFERENCE TO DATA: The ratio of the ranging modulation's maximum spectral power level, lying within the data spectrum bandwidth [data spectrum bandwidth equals the data symbol rate in Hz], to the total ranging power level, expressed as a negative value in dB. (77) REQUIRED DATA Eb / N0 : The energy per data bit divided by the noise spectral density which is required to obtain the stated Bit Error Rate, considering the improvement due to coding, expressed in dB. EARTH STATION (E/S) RECEIVING RANGING (RNG) CHANNEL PARAMETERS (78) RANGING DEMODULATOR LOSS: The loss in ranging demodulation and detection efficiency resulting from phase noise on the demodulated subcarrier, which produces a non-orthogonal, noisy phase relationship between the demodulator's reference and the i.f. carrier to be demodulated, plus losses from non-linearities in the demodulator, which reduce the device's efficiency, expressed as a negative value in dB. (79) REQUIRED TONE/CODE 1 PWR / N0 : The magnitude of range tone/code 1 ST/N0 required to achieve the desired Range accuracy, expressed as a positive or negative value in dB-Hz. (80) REQUIRED TONE/CODE 2 PWR / N0 : The magnitude of range tone/code 2 ST/N0 required to achieve the desired probability of error in the ranging measurement, expressed as a positive or negative value in dB-Hz. CCSDS 401 (4.1.3) B-1 Page 4.1.3-17 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) LINK COMPUTATIONS FOR EARTH-TO-SPACE LINK EARTH STATION (E/S) TRANSMITTING RF CARRIER CHANNEL PERFORMANCE (101) TRANSMITTER POWER: That power actually produced at the transmitter power amplifier's output terminals, expressed as a positive or negative value in dBW (10 Log10 [Watts]). (102) TRANSMIT ANTENNA GAIN [Effect]: The computed antenna gain found by subtracting the Antenna Circuit Loss and Antenna Pointing Loss from the Antenna Gain [(3)]-[(4)+(5)], expressed as a positive or negative value in dBi. (103) TRANSMIT EIRP: The computed effective isotopically radiated power found by adding Transmitter Power and Effective Antenna Gain [(101)+(102)], expressed as a positive or negative value in dBW. (104) TRANSMIT CARRIER POWER: The computed portion of the total transmitted power remaining in the rf carrier channel after subtracting the power in the sidebands due to the modulating signals, expressed as a positive or negative value in dBW. (105) TRANSMIT CARRIER POWER / PT : The power computed in (104) above, divided by the total earth station transmitted power, expressed as a negative value in dB. EARTH STATION (E/S) TRANSMITTING DATA CHANNEL PERFORMANCE (106) TRANSMIT CH 1 DATA POWER: The computed power in the rf carrier's data sidebands resulting from the modulating signal on data Channel 1, expressed as a positive or negative value in dBW. (107) TRANSMIT CH 1 DATA POWER / PT : The Channel 1 data power computed in (106) above, divided by the total earth station transmitted power, expressed as a negative value in dB. (108) TRANSMIT CH 2 DATA POWER: The computed power in the rf carrier's data sidebands resulting from the modulating signal on data Channel 2, expressed as a positive or negative value in dBW. (109) TRANSMIT CH 2 DATA POWER / PT : The Channel 2 data power computed in (108) above, divided by the total earth station transmitted power, expressed as a negative value in dB. EARTH STATION (E/S) TRANSMITTING RANGING (RNG) CHANNEL PERFORMANCE (110) TONE - CODE 1 POWER: The computed power in the rf carrier's ranging sidebands resulting from either Tone 1 (major) or Code 1 modulation, expressed as a positive or negative value in dBW. (111) TONE - CODE 1 POWER / PT : The Tone or Code 1 power computed in (110) above, divided by the total earth station transmitted power, expressed as a negative value in dB. CCSDS 401 (4.1.3) B-1 Page 4.1.3-18 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) (112) TONE - CODE 2 POWER: The computed power in the rf carrier's ranging sidebands resulting from either Tone 2 (minor) or Code 2 modulation, expressed as a positive or negative value in dBW. (113) TONE - CODE 2 POWER / PT : The Tone or Code 2 power computed in (112) above, divided by the total earth station transmitted power, expressed as a negative value in dB. EARTH-TO-SPACE PATH PERFORMANCE (114) FREE SPACE LOSS: The computed loss resulting from the spreading of the signal as it propagates from transmitting to receiving stations, expressed as a negative value in dB. (115) ATMOSPHERIC ATTENUATION: The reduction in signal power at the receiving antenna, considering such factors as the earth station's antenna elevation angle, weather, and geographical location, which results from absorption, reflection, and scattering of the rf signal as it passes through the Earth's atmosphere, placed on this page for reference purposes, expressed as a negative value in dB. (116) IONOSPHERIC LOSS: The reduction in signal power at the receiving antenna, considering such factors as the earth station's elevation angle and communication's frequency, resulting from the dispersive loss in radiated signal as it passes through the Ionosphere of the Earth and/or other bodies, placed on this page for reference purposes, expressed as a negative value in dB. SPACECRAFT (S/C) RECEIVING RF CARRIER CHANNEL PERFORMANCE (117) RECEIVING ANTENNA GAIN [Effect]: The computed antenna gain found by subtracting the Polarization Loss, Antenna Pointing Loss, and Antenna Circuit Loss from the Antenna Gain (17)- [(18)+(19)+(20)], expressed as a positive or negative value in dBi. (118) NOISE SPECTRAL DENSITY: The computed noise, generally resulting from the receiver's low noise amplifier, in a 1 Hz bandwidth, expressed in dBW/Hz. (119) THRESHOLD LOOP BW, 2 BLO : Same definition as (24) above, placed on this page for reference purposes. (120) RECEIVED CARRIER POWER: The computed carrier power in the receiver's phase locked loop bandwidth of 2 BLO , expressed as a positive or negative value in dBW. (121) CARRIER PERFORMANCE MARGIN: The computed excess in rf carrier signal over +10 dB SNR in the phase-locked-loop, which is defined to be carrier threshold, expressed in dB. CCSDS 401 (4.1.3) B-1 Page 4.1.3-19 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) SPACECRAFT (S/C) RECEIVING DATA CHANNEL PERFORMANCE (122) CH 1 DATA LOSS DUE TO RNG: The computed loss in data channel's performance resulting from the presence of a simultaneous ranging signal on the earth-to-space link, expressed in dB. (123) RECEIVED CH 1 Eb / N0 : The computed received energy per bit in Data Channel 1 divided by the noise spectral density, expressed in dB. (124) REQUIRED CH 1 Eb / N0 : The computed energy per bit divided by the noise spectral density (Eb / N0) found by adding the Phase Jitter Loss, Demodulator/Detector Loss, Waveform Distortion Loss, and Maximum Ranging Interference to Data to the Required Data Eb / N0 [(29)] + [(25)+(26)+(27)+(28)], expressed in dB. (125) CH 1 DATA PERFORMANCE MARGIN: The computed excess of Channel 1 received Eb / N0 over the required Eb / N0 , [(123)-(124)], expressed in dB. (126) CH 2 DATA LOSS DUE TO RNG: Same definition as (122) above except that it is applicable to data channel 2. (127) RECEIVED CH 2 Eb / N0 : Same definition as (123) above except that it is applicable to data channel 2. (128) REQUIRED CH 2 Eb / N0 : Same definition as (124) above except that it is applicable to data channel 2. (129) CH 2 DATA PERFORMANCE MARGIN: The computed excess of Channel 2 received Eb / N0 over the required Eb / N0 ,[(127)-(128)], expressed in dB. SPACECRAFT (S/C) RECEIVING RANGING (RNG) CHANNEL PERFORMANCE (130) RECEIVED CODE 1 POWER / N0 : The computed received power (PR) in the ranging Tone 1 (major) or Code 1 divided by the noise spectral density, expressed as a positive or negative value in dB- Hz. (131) RECEIVED CODE 2 POWER / N0 : Same definition as (130) above except that it is applicable to Tone or Code 2. (132) RECEIVED TOTAL RNG POWER / N0 : The computed total received power in all ranging Tones or Codes, if several are present simultaneously, or Tone/Code 1 if Tones or Codes are transmitted sequentially, divided by the noise spectral density, expressed as a positive or negative value in dB-Hz. (133) RANGING MARGIN: The computed excess of received total ranging power over the required ranging power, expressed in dB. CCSDS 401 (4.1.3) B-1 Page 4.1.3-20 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) LINK COMPUTATIONS FOR SPACE-TO-EARTH LINK SPACECRAFT (S/C) TRANSMITTING RF CARRIER CHANNEL PERFORMANCE (151) TRANSMITTER POWER: That power actually produced at the transmitter power amplifier's output terminals, expressed as a positive or negative value in dBW (10 Log10 [Watts]). (152) TRANSMIT ANTENNA GAIN [Effect]: The computed antenna gain found by subtracting the Antenna Circuit Loss and Antenna Pointing Loss from the Antenna Gain (53)-[(54)+(55)], expressed as a positive or negative value in dBi. (153) TRANSMIT EIRP: The computed effective isotopically radiated power found by adding Transmitter Power and Effective Antenna Gain [(151)+(152)], expressed as a positive or negative value in dBW. (154) TRANSMIT CARRIER POWER: The computed portion of the total transmitted power remaining in the rf carrier channel after subtracting the power in the sidebands due to the modulating signals, expressed as a positive or negative value in dBW. (155) TRANSMIT CARRIER POWER / PT : The power computed in (154) above, divided by the total spacecraft transmitted power, expressed as a negative value in dB. SPACECRAFT (S/C) TRANSMITTING DATA CHANNEL PERFORMANCE (156) TRANSMIT CH 1 DATA POWER: The computed power in the rf carrier's data sidebands resulting from the modulating signal on data Channel 1, expressed as a positive or negative value in dBW. (157) TRANSMIT CH 1 DATA POWER / PT : The Channel 1 data power computed in (156) above, divided by the total spacecraft transmitted power, expressed as a negative value in dB. (158) TRANSMIT CH 2 DATA POWER: The computed power in the rf carrier's data sidebands resulting from the modulating signal on data Channel 2, expressed as a positive or negative value in dBW. (159) TRANSMIT CH 2 DATA POWER / PT : The Channel 2 data power computed in (158) above, divided by the total spacecraft transmitted power, expressed as a negative value in dB. SPACECRAFT (S/C) TRANSMITTING RANGING (RNG) CHANNEL PERFORMANCE (160) TONE - CODE 1 POWER: The computed power in the rf carrier's ranging sidebands resulting from either Tone 1 (major) or Code 1 modulation, expressed as a positive or negative value in dBW. (161) TONE - CODE 1 POWER / PT : The Tone or Code 1 power computed in (160) above, divided by the total earth station transmitted power, expressed as a negative value in dB. CCSDS 401 (4.1.3) B-1 Page 4.1.3-21 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) (162) TONE - CODE 2 POWER: The computed power in the rf carrier's ranging sidebands resulting from either Tone 2 (major) or Code 2 modulation, expressed as a positive or negative value in dBW. (163) TONE - CODE 2 POWER / PT : The Tone or Code 2 power computed in (162) above, divided by the total spacecraft transmitted power, expressed as a negative value in dB. SPACE-TO-EARTH PATH PERFORMANCE (164) FREE SPACE LOSS: The computed loss resulting from the spreading of the signal as it propagates from transmitting to receiving station, expressed as a negative value in dB. (165) ATMOSPHERIC ATTENUATION: The reduction in signal power at the receiving antenna, considering such factors as the earth station's antenna elevation angle, weather, and geographical location, which results from absorption, reflection, and scattering of the rf signal as it passes through the Earth's atmosphere, placed on this page for reference purposes, expressed as a negative value in dB. (166) IONOSPHERIC LOSS: The reduction in signal power at the receiving antenna, considering such factors as the earth station's elevation angle and communication's frequency, resulting from the dispersive loss in radiated signal as it passes through the Ionosphere of the Earth and/or other bodies, placed on this page for reference purposes, expressed as a negative value in dB. EARTH STATION (E/S) RECEIVING RF CARRIER CHANNEL PERFORMANCE (167) RECEIVING ANTENNA GAIN [Effect]: The computed antenna gain found by subtracting the Polarization Loss, Antenna Pointing Loss, and Antenna Circuit Loss from the Antenna Gain (66)- [(67)+(68)+(69)], expressed as a positive or negative value in dBi. (168) NOISE SPECTRAL DENSITY: The computed noise, generally resulting from the receiver's low noise amplifier, in a 1 Hz bandwidth, expressed in dBW/Hz. (169) THRESHOLD LOOP BW, 2 BLO : Same definition as (71) above, placed on this page for reference purposes. (170) RECEIVED CARRIER POWER: The computed carrier power in the receiver's phase locked loop bandwidth of 2 BLO , expressed in dBW. (171) CARRIER PERFORMANCE MARGIN: The computed excess in rf carrier signal over +10 dB SNR in the phase-locked-loop, which is defined to be carrier threshold, expressed in dB. CCSDS 401 (4.1.3) B-1 Page 4.1.3-22 September 1989 4.1.3 ANNEX TO RECOMMENDATION (Continued) EARTH STATION (E/S) RECEIVING DATA CHANNEL PERFORMANCE (172) CH 1 DATA LOSS DUE TO RNG: The computed loss in data channel's performance resulting from the presence of a simultaneous ranging signal on the space-to-earth link, expressed in dB. (173) RECEIVED CH 1 Eb / N0 : The computed received energy per bit in Data Channel 1 divided by the noise spectral density, expressed in dB. (174) REQUIRED CH 1 Eb / N0 : The computed energy per bit divided by the noise spectral density (Eb / N0) found by adding the Phase Jitter Loss, Demodulator/Detector Loss, Waveform Distortion Loss, and Maximum Ranging Interference to Data to the Required Data Eb / N0 [(77)] + [(73)+(74)+(75)+(76)], [includes the improvement due to coding], expressed in dB. (175) CH 1 DATA PERFORMANCE MARGIN: The computed excess of Channel 1 received Eb / N0 over the required Eb / N0 , [(173)-(174)], expressed in dB. (176) CH 2 DATA LOSS DUE TO RNG: Same definition as (172) above except that it is applicable to data channel 2. (177) RECEIVED CH 2 Eb / N0 : Same definition as (173) above except that it is applicable to data channel 2. (178) REQUIRED CH 2 Eb / N0 : Same definition as (174) above except that it is applicable to data channel 2. (179) CH 2 DATA PERFORMANCE MARGIN: The computed excess of Channel 2 received Eb / N0 over the required Eb / N0 , [(177)-(178)], expressed in dB. EARTH STATION (E/S) RECEIVING RANGING (RNG) CHANNEL PERFORMANCE (180) RECEIVED CODE 1 POWER / N0 : The computed received power (PR) in the ranging Tone 1 (major) or Code 1 divided by the noise spectral density, expressed as a positive or negative value in dB- Hz. (181) RECEIVED CODE 2 POWER / N0 : Same definition as (180) above except that it is applicable to Tone or Code 2. (182) RECEIVED TOTAL RNG POWER / N0 : The computed total received power in all ranging Tones or Codes, if several are present simultaneously, or Tone/Code 1 if Tones or Codes are transmitted sequentially, divided by the noise spectral density, expressed as a positive or negative value in dB-Hz. (183) RANGING PERFORMANCE MARGIN: The computed excess of received total ranging power over the required ranging power, expressed in dB. CCSDS 401 (4.1.3) B-1 Page 4.1.3-23 September 1989 4.1.4 DEFAULT PROBABILITY DENSITY FUNCTIONS FOR LINK COMPUTATION IN THE CCSDS TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE The CCSDS, considering (a) that several parameters used in the telecommunications link Design Control Table (DCT) [CCSDS Recommendation 401 (4.1.2) B-1] are random variables whose values can only be estimated using statistical methods; (b) that such statistical computations require a knowledge of the statistical properties of the non-deterministic parameters; (c) that a Probability Density Function (PDF) is useful in representing the statistical properties of a random variable; (d) that the PDFs, shown in Figure 4.1.4-1 of the Annex, are considered to be sufficient to estimate the statistical values of the parameters in the telecommunications link DCT; (e) that empirical evidence, obtained from many years of experience in telecommunication link design, demonstrates that the PDFs, published in References [1] and [2] and reproduced in Tables 4.1.4- 1 and 4.1.4-2 of the Annex hereto, provide the best estimates of the statistical values for the named parameters; (f) that many of the non-deterministic parameters found in the CCSDS link DCT [CCSDS Recommendation 401 (4.1.2) B-1] are independent of the specific implementation methods used by agencies in their earth stations and spacecraft while others are not; recommends (1) that CCSDS agencies employ the three PDFs shown in Figure 4.1.4-1 of the Annex to approximate the PDFs of parameters found in the CCSDS link DCT, when computing their statistical values; (2) that, when a CCSDS Agency has not independently specified some, or all, of the PDFs, the default set of PDFs shown in Tables 4.1.4-1 and 4.1.4-2 of the Annex hereto should be used to estimate the value of the correspondingly named parameter; (3) that, where a CCSDS Agency has specified some, or all, of the PDFs for non-deterministic parameters, either the Agency's set of PDFs or the default set of PDFs, found in Tables 4.1.4-1 and 4.1.4-2, may be used. REFERENCES 1. Joseph Yuen, Editor, "Deep Space Telecommunications Systems Engineering," Plenum Press, New York, 1983, Chapter 1. 2. Joseph Yuen, "A Practical Statistical Model for Telecommunications Performance Uncertainty," Technical Memorandum 33-732, NASA/Jet Propulsion Laboratory, California Institute Of Technology, Pasadena, June 15, 1975. CCSDS 401 (4.1.4) B-1 Page 4.1.4-1 September 1991 4.1.4 DEFAULT PROBABILITY DENSITY FUNCTIONS FOR LINK COMPUTATION IN THE CCSDS TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE (Continued) [IMAGE] 6445-442ab FIGURE 4.1.4-1: PROBABILITY DENSITY FUNCTIONS D = Design value, in dB [...] = Mean value, in dB [...]2 = Variance, in dB2 A = Adverse tolerance, which is defined as the worst case of a parameter minus the design value in dB. Adverse tolerance generally has a negative value for all link parameters except noise spectral density and noise bandwidth. F = Favorable tolerance, which is defined as the best case of a parameter minus the design value in dB. Favorable tolerance generally has a positive value for all link parameters except noise spectral density and noise bandwidth. NOTE: The above formulas assume that (D + A) and (D + F) are at ([...] ñ 3[...]) points. CCSDS 401 (4.1.4) B-1 Page 4.1.4-2 September 1991 4.1.4 DEFAULT PROBABILITY DENSITY FUNCTIONS FOR LINK COMPUTATION IN THE CCSDS TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE (Continued) ANNEX TABLE 4.1.4-1: EARTH-TO-SPACE (UPLINK) DATA ELEMENT TYPES Element Description Probability Number Density Function 3 Antenna Gain Uniform 4 Antenna Circuit Loss (TX) Uniform 5 Antenna Pointing Loss (TX) Uniform 17 S/C Antenna Gain Triangular 18 Polarization Loss (RX) Uniform 19 S/C Antenna Pointing Loss (RX) Triangular 20 S/C Antenna Circuit Loss (RX) Uniform 21 Carrier Circuit Loss Triangular 25 Phase Jitter Loss Uniform 26 Demodulator/Detec tor Loss Triangular 27 Waveform Distortion Loss Uniform 28 Maximum Ranging Interference to Data Deterministic 30 Ranging Demodulation Loss Triangular 101 Station Transmitter Power Triangular 102 Trans. Ant. Gain [Effective] Uniform 103 Transmitting EIRP Triangular 104 Transmitted Carrier Power Triangular 105 Trans. Carrier Power/PT Triangular 106 Trans. Chan. 1 Data Power Triangular 107 Trans. Chan. 1 Data Power/PT Triangular 108 Trans. Chan. 2 Data Power Triangular 109 Trans. Chan. 2 Data Power/PT Triangular 110 Tone - Code 1 Power Triangular CCSDS 401 (4.1.4) B-1 Page 4.1.4-3 September 1991 4.1.4 DEFAULT PROBABILITY DENSITY FUNCTIONS FOR LINK COMPUTATION IN THE CCSDS TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE (Continued) ANNEX TABLE 4.1.4-1: EARTH-TO-SPACE (UPLINK) DATA ELEMENT TYPES (Continued) Element Description Probability Number Density Function 111 Tone - Code 1 Power/PT Triangular 112 Tone - Code 2 Power Triangular 113 Tone - Code 2 Power/PT Triangular 114 Free Space Loss Triangular 115 Atmospheric Attenuation Gaussian 116 Ionospheric Loss Gaussian 117 Receiving Antenna Gain [Effective] Uniform 118 Noise Spectral Density Gaussian 119 Threshold Loop BW, 2BLO Triangular 120 Received Carrier Power Triangular 121 Carrier Performance Margin Triangular 122 Channel 1 Data Loss Due to Ranging Triangular 123 Received Channel 1 Eb/N0 Triangular 124 Required Channel 1 Eb/N0 Deterministic 125 Channel 1 Data Performance Margin Triangular 126 Channel 2 Data Loss Due to Ranging Triangular 127 Received Channel 1 Eb/N0 Triangular 128 Required Channel 2 Eb/N0 Deterministic 129 Channel 2 Data Performance Margin Triangular 130 Received Code 1 Power/N0 Triangular 131 Received Code 2 Power/N0 Triangular 132 Rcvd Total Ranging Power/N0 Triangular 133 Ranging Power at S/C Receiver Output (Uplink Ranging Margin) Triangular CCSDS 401 (4.1.4) B-1 Page 4.1.4-4 September 1991 4.1.4 DEFAULT PROBABILITY DENSITY FUNCTIONS FOR LINK COMPUTATION IN THE CCSDS TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE (Continued) ANNEX TABLE 4.1.4-2: SPACE-TO-EARTH (DOWNLINK) DATA ELEMENT TYPES Element Description Probability Number Density Function 53 S/C Antenna Gain Triangular 54 S/C Antenna Circuit Loss (TX) Uniform 55 Antenna Pointing Loss (TX) Triangular 66 E/S Antenna Gain Uniform 67 Polarization Loss (RX) Uniform 68 Antenna Pointing Loss (RX) Uniform 69 Antenna Circuit Loss (RX) Uniform 70a Receiver Operating Temperature Gaussian 70b Feed Through Noise Gaussian 70c Hot Body Noise Gaussian 70d Weather Temperature Increase Gaussian 73 Phase Jitter Loss Uniform 74 Demodulator/Detec tor Loss Triangular 75 Waveform Distortion Loss Uniform 76 Maximum Ranging Interference to Data Deterministic 78 Ranging Demodulation Loss Triangular 151 S/C Transmitter Power Triangular 152 Trans. Ant. Gain [Effective] Uniform 153 Transmitting EIRP Triangular 154 Transmitted Carrier Power Triangular 155 Trans. Carrier Power/PT Triangular 156 Trans. Chan. 1 Data Power Triangular 157 Trans. Chan. 1 Data Power/PT Triangular 158 Trans. Chan. 2 Data Power Triangular CCSDS 401 (4.1.4) B-1 Page 4.1.4-5 September 1991 4.1.4 DEFAULT PROBABILITY DENSITY FUNCTIONS FOR LINK COMPUTATION IN THE CCSDS TELECOMMUNICATIONS LINK DESIGN CONTROL TABLE (Continued) ANNEX TABLE 4.1.4-2: SPACE-TO-EARTH (DOWNLINK) DATA ELEMENT TYPES (Con tinued) Element Description Probability Number Density Function 159 Trans. Chan. 2 Data Power/PT Triangular 160 Tone - Code 1 Power Triangular 161 Tone - Code 1 Power/PT Triangular 162 Tone - Code 2 Power Triangular 163 Tone - Code 2 Power/PT Triangular 164 Free Space Loss Triangular 165 Atmospheric Attenuation Gaussian 166 Ionospheric Loss Gaussian 167 Receiving Antenna Gain [Effective] Uniform 168 Noise Spectral Density Gaussian 169 Threshold Loop BW, 2BLO Triangular 170 Received Carrier Power Triangular 171 Carrier Performance Margin Gaussian 172 Chan. 1 Data Loss Due to Ranging Triangular 173 Received Channel 1 Eb/N0 Triangular 174 Required Channel 1 Eb/N0 Deterministic 175 Channel 1 Data Performance Margin Gaussian 176 Chan. 2 Data Loss Due to Ranging Triangular 177 Received Channel 2 Eb/N0 Triangular 178 Required Channel 2 Eb/N0 Deterministic 179 Channel 2 Data Performance Margin Gaussian 180 Received Code 1 Power/N0 Triangular 181 Received Code 2 Power/N0 Triangular 182 Rcvd Total Ranging Power/N0 Triangular 183 Ranging Margin Gaussian CCSDS 401 (4.1.4) B-1 Page 4.1.4-6 September 1991 4.1.5 COMPUTATIONAL TECHNIQUE FOR THE MEAN AND VARIANCE OF THE MODULATION LOSSES FOUND IN THE CCSDS TELECOMMUNICATION LINK DESIGN CONTROL TABLE The CCSDS, considering (a) that the term "modulation loss" as used in the CCSDS Link Design Control Table (DCT) [CCSDS Recommendation 401 (4.1.2) B-1] means "that fraction of the total transmitted power allotted to a designated channel"; (b) that the computation of the carrier, telecommand, telemetry and ranging link margins found in the CCSDS DCT requires an evaluation of the modulation losses; (c) that the CCSDS DCT employs a statistical technique for computing the mean and variance of modulation losses for which most input parameters in the DCT require the specification of a design value together with its favorable and adverse tolerances; (d) that computation of the modulation loss tolerances are based upon variations at the peak phase deviations (peak modulation indices); (e) that the calculation of the variance on link performance can be tedious because it requires the designer to evaluate the several modulation losses for all possible combinations of favorable and adverse tolerances; (f) that, for systems employing a coherent-turnaround ranging channel with a constant-power AGC simultaneously with telecommand and telemetry (Figure 4.1.5-1), there are 128 possible combinations of favorable and adverse tolerances affecting the several modulation losses which must be evaluated to compute the telemetry channel's performance; (g) that computing a telecommunication system's performance by evaluating all possible combinations of favorable and adverse tolerances on the several modulation loss input parameters results in an unnecessary increase in computational complexity since the combinations producing the extreme performance variations are deterministic; (h) that based on the mathematical expressions for the modulation losses, simple algorithms can be developed to avoid this unnecessary increase in computational complexity; (i) that, due to the modulation schemes recommended by the CCSDS, [CCSDS Recommendations 401 (2.2.2) B-1, 401 (2.2.3) B-1, 401 (2.3.1) B-1, 401 (2.4.2) B-1, 401 (2.4.3) B-1, 401 (2.4.4) B-1 and 401 (2.4.5) B-1], computation of tolerances on the several modulation losses requires the use of Bessel, trigonometric and exponential functions; (j) that, when the maximum modulation indices are less than 1.4 radians [see CCSDS Recommendations 401 (2.1.6) B-1 and 401 (2.3.8) B-2], the maximum and minimum values of some modulation losses do not occur when all modulation indices are simultaneously at their upper or lower bounds, respectively (see Figure 4.1.5-2); CCSDS 401 (4.1.5) B-1 Page 4.1.5-1 June 1993 4.1.5 COMPUTATIONAL TECHNIQUE FOR THE MEAN AND VARIANCE OF THE MODULATION LOSSES FOUND IN THE CCSDS TELECOMMUNICATION LINK DESIGN CONTROL TABLE (Continued) (k) that a common set of computation algorithms will ease the information exchange between space agencies; recommends (1) that parameters defined in Tables 4.1.5-1a and 4.1.5-1b be used in the formulas for the computation of the maxima and minima of the modulation losses; (2) that Algorithm 1 be used to compute the mean and variance of the earth-to-space modulation losses for simultaneous range and telecommand operations using sinewave subcarriers; (3) that Algorithm 2 be used to compute the mean and variance of the space-to-earth modulation losses when a power-controlled AGC is employed on the turnaround ranging channel. CCSDS 401 (4.1.5) B-1 Page 4.1.5-2 June 1993 4.1.5 COMPUTATIONAL TECHNIQUE FOR THE MEAN AND VARIANCE OF THE MODULATION LOSSES FOUND IN THE CCSDS TELECOMMUNICATION LINK DESIGN CONTROL TABLE (Continued) ANNEX TO RECOMMENDATION 4.1.5 TABLE 4.1.5-1a: Definitions of Parameters in Uplink Modulation Loss Formulas mCD = telecommand peak modulation index; mR1 = uplink peak ranging modulation index; PT1 = total uplink signal power; PC1, PCD, PR1 = uplink carrier, telecommand and ranging powers, respectively; N01 = uplink noise power spectral density. TABLE 4.1.5-1b: Definitions of Parameters in Downlink Modulation Loss Formulas mTM1 , mTM2 = telemetry channels 1 and 2 peak modulation indices; mR2 = downlink peak ranging modulation index; PT2 = total downlink signal power; PC2, PTM1, PTM2, PR2 = powers of downlink carrier, of telemetry channels 1 and 2 and of ranging, respectively. Ranging Modulation Type Coefficient: [...] if only the fundamental harmonic of an uplink ranging square wave signal passes through the transponder's ranging filter; [...] = 1 if a sinusoidal ranging signal is modulated on the uplink carrier. Actual (noise-modified) modulation indices for feed-through command (peak), ranging (peak) and noise (rms), respectively: [...]1 = mR2 [...], [...]2 = mR2 [...], [...]3 = [...] [...]R = [...]: ranging signal-to-noise power ratio at the output of the transponder filter; [...]C = [...] : feed-through telecommand-to-noise power ratio at the transponder ranging filter's output (with no telecommand subcarrier attenuation); BR = one-sided bandwidth of the transponder ranging channel. CCSDS 401 (4.1.5) B-1 Page 4.1.5-3 June 1993 4.1.5 COMPUTATIONAL TECHNIQUE FOR THE MEAN AND VARIANCE OF THE MODULATION LOSSES FOUND IN THE CCSDS TELECOMMUNICATION LINK DESIGN CONTROL TABLE (Continued) ANNEX TO RECOMMENDATION 4.1.5 (Continued) ALGORITHM 1 : Computation of the Mean and Variance of Uplink Modulation Losses. 1. Compute the maxima and minima of uplink ranging and telecommand modulation indices by adding the favorable and adverse tolerances to the nominal values of the modulation indices. 2. Compute the nominal uplink modulation losses by substituting the nominal (design) modulation index values in the modulation loss equations in Table 4.1.5-2: TABLE 4.1.5- 2: Nominal Uplink Modulation Losses Channel Square-Wave Ranging Sinusoidal Ranging [...] = cos2(mR1)J [...] = J Carrier [...](mCD) [...](mR1)J [...](mCD) [...] = 2cos2(mR1)J [...] = 2J Telecommand [...](mCD) [...](mR1)J [...](mCD) [...] = sin2(mR1)J [...] = 2J Ranging [...](mCD) [...](mR1)J [...](mCD) 3. Compute minima and maxima of uplink modulation losses using the equations of Table 4.1.5-3, as shown in Tables 4.1.5-3a and 4.1.5-3b: TABLE 4.1.5-3a: Minima and Maxima of Uplink Modulatio n Losses / Square- Wave Ranging [...]= cos2(mR1(min))J [...]= cos2(mR1(max))J Carrier [...](mCD(min)) [...](mCD(max)) [...]= 2cos2(mR1(min))J [...]= 2cos2(mR1(max))J Tele- [...](mCD(max)) [...](mCD(min)) command [...]= sin2(mR1(max))J [...]= sin2(mR1(min))J Ranging [...](mCD(min)) [...](mCD(max)) CCSDS 401 (4.1.5) B-1 Page 4.1.5-4 June 1993 4.1.5 COMPUTATIONAL TECHNIQUE FOR THE MEAN AND VARIANCE OF THE MODULATION LOSSES FOUND IN THE CCSDS TELECOMMUNICATION LINK DESIGN CONTROL TABLE (Continued) ANNEX TO RECOMMENDATION 4.1.5 (Continued) TABLE 4.1.5-3b: Minima and Maxima of Uplink Modulatio n Losses / Sine- Wave Ranging [...]= J [...](mR1(min))J [...]= J [...](mR1(max))J Carrier [...](mCD(min)) [...](mCD(max)) [...]= 2J [...](mR1(min))J [...]= 2J [...](mR1(max))J Tele- [...](mCD(max)) [...](mCD(min)) command [...]= 2J [...](mR1(max))J [...]= 2J [...](mR1(min))J Ranging [...](mCD(min)) [...](mCD(max)) 4. Compute the tolerances of the modulation losses using the following formulas: (a) Favorable Tolerance: Fx = [...](max) - [...](nominal); and (b) Adverse Tolerance: Ax = [...](min) - [...](nominal); where x = C1, CD or R1. 5. Compute the mean and variance of the uplink modulation losses, using the PDF assigned to each modulation loss in accordance with CCSDS Recommendation 401 (4.1.4) B-1. ALGORITHM 2 : Computation of the Mean and Variance of Downlink Modulation Losses 1. Compute the maxima and minima of downlink ranging and telemetry modulation indices by adding the favorable and adverse tolerances to the nominal values of the modulation indices. 2. Compute the minima and maxima of actual modulation indices [...]1, [...]2, [...]3 for feed through command, ranging and noise, respectively (see parameter definitions in Table 4.1.5-1b). Note: Signal-to-noise ratios [...]R, [...]C depend on uplink parameters and the ranging channel's bandwidth; therefore, [...]R, [...]C maximization or minimization is obtained by substituting the maxima and/or minima of uplink parameters in the [...]R, [...]C expressions as shown in Table 4.1.5-5. CCSDS 401 (4.1.5) B-1 Page 4.1.5-5 June 1993 4.1.5 COMPUTATIONAL TECHNIQUE FOR THE MEAN AND VARIANCE OF THE MODULATION LOSSES FOUND IN THE CCSDS TELECOMMUNICATION LINK DESIGN CONTROL TABLE (Continued) ANNEX TO RECOMMENDATION 4.1.5 (Continued) TABLE 4.1.5-4: Maxima and Minima of Actual Downlink Modulation Indices [...]1(max) = [...] [...]1(min) = [...] [...]2(max) = [...] [...]2(min) = [...] [...]3(max) = [...] [...]3(min) = [...] 3. Compute the nominal downlink modulation losses by substituting the nominal (design) values in the expressions in Tables 4.1.5-5a, 4.1.5-5b, and 4.1.5-5c assuming that only the first harmonic of the square wave ranging signal passes through the transponder's ranging filter or that a sinewave ranging signal is used. TABLE 4.1.5-5a: Modulation Losses Downlink Carrier, Two- Channel/Square- Wave Telemetry, and Ranging [...]= cos2(mTM1)cos2(mTM2)J [...]([...]1)J Carrier [...]([...]2)e[...] [...]= sin2(mTM1)cos2(mTM2)J [...]([...]1)J Telemetry [...]([...]2)e[...] Channel 1 [...]= cos2(mTM1)sin2(mTM2)J [...]([...]1)J Telemetry [...]([...]2)e[...] Channel 2 [...]= 2cos2(mTM1)cos2(mTM2)J [...]([...]1)J Ranging [...]([...]2)e[...] CCSDS 401 (4.1.5) B-1 Page 4.1.5-6 June 1993 4.1.5 COMPUTATIONAL TECHNIQUE FOR THE MEAN AND VARIANCE OF THE MODULATION LOSSES FOUND IN THE CCSDS TELECOMMUNICATION LINK DESIGN CONTROL TABLE (Continued) ANNEX TO RECOMMENDATION 4.1.5 (Continued) TABLE 4.1.5-5b: Modulation Losses Downlink Carrier, Two- Channel / Sine- Wave Telemetry, and Ranging [...]= J [...](mTM1)J [...](mTM2)J Carrier [...]([...]1)J [...]([...]2)e[...] Telemetry [...]= 2J [...](mTM1)J [...](mTM2)J Channel 1 [...]([...]1)J [...]([...]2)e[...] Telemetry [...]= 2J [...](mTM1)J [...](mTM2)J Channel 2 [...]([...]1)J [...]([...]2)e[...] [...]= 2J [...](mTM1)J [...](mTM2)J Ranging [...]([...]1)J [...]([...]2)e[...] TABLE 4.1.5-5c: Modulation Losses Downlink Carrier, Two- Channel / Square and Sine Wave Telemetry, and Ranging [...]= cos2(mTM1)J [...](mTM2)J [...]([...]1)J Carrier [...]([...]2)e[...] Telemetry [...]= sin2(mTM1)J [...](mTM2)J [...]([...]1)J Channel 1 [...]([...]2)e[...] Telemetry [...]= 2cos2(mTM1)J [...](mTM2)J [...]([...]1)J Channel 2 [...]([...]2)e[...] [...]= 2cos2(mTM1)J [...](mTM2)J [...]([...]1)J Ranging [...]([...]2)e[...] 4. Compute lower and upper bounds of the downlink modulation loss minima and maxima by substituting the minima and maxima of modulation indices mTM1, mTM2, [...]1, [...]2, [...]3 in the expressions of Tables 4.1.5-6a, 4.1.5-6b and 4.1.5-6c. These lower and upper bounds (denoted lb and ub, respectively) of modulation loss minima and maxima as computed in Tables 4.1.5-7a, 4.1.5-7b, 4.1.5-7c differ with respect to the actual minima and maxima of the modulation losses because [...]1, [...]2, [...]3 are not independent variables. However, extensive computations demonstrated that the difference is always less than 0.1 dB, for the applicable ranges of modulation indices mTM1, mTM2, [...]1, [...]2, [...]3. CCSDS 401 (4.1.5) B-1 Page 4.1.5-7 June 1993 4.1.5 COMPUTATIONAL TECHNIQUE FOR THE MEAN AND VARIANCE OF THE MODULATION LOSSES FOUND IN THE CCSDS TELECOMMUNICATION LINK DESIGN CONTROL TABLE (Continued) ANNEX TO RECOMMENDATION 4.1.5 (Continued) TABLE 4.1.5- 6a: Downlink Modulation Loss Maxima and Minima / Square-Wave Telemetry [...](ub) = cos2(mTM1(min))cos2(mTM2(min))J [...]([...]1(min))J [...]([...]2(min))e[...] Carrier [...](lb) = cos2(mTM1(max))cos2(mTM2(max))J [...]([...]1(max))J [...]([...]2(max))e[...] [...](ub) = sin2(mTMi(max))cos2(mTMj(min))J [...]([...]1(min))J [...]([...]2(min))e[...] Telemetry i, j=1, 2 i[...]j [...](lb) = sin2(mTMi(min))cos2(mTMj(max))J [...]([...]1(max))J [...]([...]2(max))e[...] [...](ub) = 2cos2(mTM1(min))cos2(mTM2(min))J [...]([...]1(min))J [...]([...]2(max))e[...] Ranging [...](lb) = 2cos2(mTM1(max))cos2(mTM2(max))J [...]([...]1(max))J [...]([...]2(min))e[...] TABLE 4.1.5- 6b: Downlink Modulation Loss Maxima and Minima / Sine-Wave Telemetry [...](ub) = J [...](mTM1(min))J [...](mTM2(min))J [...]([...]1(min))J [...]([...]2(min))e[...] Carrier [...](lb) = J [...](mTM1(max))J [...](mTM2(max))J [...]([...]1(max))J [...]([...]2(max))e[...] [...](ub) = 2J [...](mTMi(max))J [...](mTMj(min))J [...]([...]1(min))J [...]([...]2(min))e[...] Telemetry i, j=1, 2 i[...]j [...](lb) = 2J [...](mTMi(min))J [...](mTMj(max))J [...]([...]1(max))J [...]([...]2(max))e[...] [...](ub) = 2J [...](mTM1(min))J [...](mTM2(min))J [...]([...]1(min))J [...]([...]2(max))e[...] Ranging [...](lb) = 2J [...](mTM1(max))J [...](mTM2(max))J [...]([...]1(max))J [...]([...]2(min))e[...] CCSDS 401 (4.1.5) B-1 Page 4.1.5-8 June 1993 4.1.5 COMPUTATIONAL TECHNIQUE FOR THE MEAN AND VARIANCE OF THE MODULATION LOSSES FOUND IN THE CCSDS TELECOMMUNICATION LINK DESIGN CONTROL TABLE (Continued) ANNEX TO RECOMMENDATION 4.1.5 (Continued) TABLE 4.1.5- 6c: Downlink Modulation Loss Maxima and Minima / Square and Sine Wave Telemetry [...](ub) = cos2(mTM1(min))J [...](mTM2(min))J [...]([...]1(min))J [...]([...]2(min))e[...] Carrier [...](lb) = cos2(mTM1(max))J [...](mTM2(max))J [...]([...]1(max))J [...]([...]2(max))e[...] [...](ub) = sin2(mTM1(max))J [...](mTM2(min))J Telemetry [...]([...]1(min))J [...]([...]2(min))e[...] Channel 1 Square Wave [...](lb) = sin2(mTM1(min))J [...](mTM2(max))J [...]([...]1(max))J [...]([...]2(max))e[...] [...](ub) = 2cos2(mTM1(min))J [...](mTM2(max))J Telemetry [...]([...]1(min))J [...]([...]2(min))e[...] Channel 2 Sine Wave [...](lb) = 2cos2(mTM1(max))J [...](mTM2(min))J [...]([...]1(max))J [...]([...]2(max))e[...] [...](ub) = 2cos2(mTM1(min))J [...](mTM2(min))J [...]([...]1(min))J [...]([...]2(max))e[...] Ranging [...](lb) = 2cos2(mTM1(max)) J [...](mTM2(max))J [...]([...]1(max))J [...]([...]2(min))e[...] 5. Compute the tolerances of downlink modulation losses, using formulas as in Algorithm 1 Part 4 with x = C2, TM1, TM2, and R2. 6. Compute the mean and variance of the downlink modulation losses, using the PDF assigned to each modulation loss. CCSDS 401 (4.1.5) B-1 Page 4.1.5-9 June 1993 4.1.5 COMPUTATIONAL TECHNIQUE FOR THE MEAN AND VARIANCE OF THE MODULATION LOSSES FOUND IN THE CCSDS TELECOMMUNICATION LINK DESIGN CONTROL TABLE (Continued) ANNEX TO RECOMMENDATION 4.1.5 (Continued) [IMAGE] 6445-443ab FIGURE 4.1.5-1: SIMPLIFIED BLOCK DIAGRAM FOR TWO-WAY SIMULTANEOUS TELECOMMAND/RANGING AND TELEMETRY/RANGING OPERATIONS CCSDS 401 (4.1.5) B-1 Page 4.1.5-10 June 1993 4.1.5 COMPUTATIONAL TECHNIQUE FOR THE MEAN AND VARIANCE OF THE MODULATION LOSSES FOUND IN THE CCSDS TELECOMMUNICATION LINK DESIGN CONTROL TABLE (Continued) ANNEX TO RECOMMENDATION 4.1.5 (Continued) [IMAGE] 6445-446ab FIGURE 4.1.5-2: BESSEL, TRIGONOMETRIC, AND EXPONENTIAL CURVES FOR 0 TO [...]/2 RADIANS CCSDS 401 (4.1.5) B-1 Page 4.1.5-11 June 1993 4.2.1 COMPUTATIONAL METHOD FOR DETERMINING THE OCCUPIED BANDWIDTH OF UNFILTERED PCM/PM SIGNALS The CCSDS, considering (a) that the occupied bandwidth is defined as that band of frequencies which contain 99% of the total radiated power (ITU RR 147); (b) that the occupied bandwidth of unfiltered modulated signals provides a useful indication as to whether filtering may be necessary to optimally use the allocated frequency band; (c) that a simple, closed-form expression for calculating the occupied bandwidth of PCM/PM signals, using either NRZ or Bi-Phase formats, is not available; (d) that approximations for computing occupied bandwidth of PCM/PM signals, having an accuracy of better than 90% over the specified ranges of modulation indices, have been developed and are compared with theoretical values in Figure 4.2.1-1; recommends that the occupied bandwidth of PCM/PM signals containing 99% of the total radiated power can be calculated, with an accuracy of better than 90%, using the following approximations: BW = 2 x (26.2m - 5.16)RS for Bi-Phase format: (0.4 rads. [...] m [...] 1.4 rads.); BW = 2 x (8.93m - 1.75)RS for NRZ format: (0.4 rads. [...] m [...] 1.4 rads.); NOTES: BW = Occupied Bandwidth is the band of frequencies containing 99% of the total radiated power, RS = Modulated Symbol Rate, m = Modulation Index (in radians). CCSDS 401 (4.2.1) B-1 Page 4.2.1-1 June 1993 4.2.1 COMPUTATIONAL METHOD FOR DETERMINING THE OCCUPIED BANDWIDTH OF UNFILTERED PCM/PM SIGNALS (Continued) [IMAGE] 6445-444ab FIGURE 4.2.1-1: COMPARISON OF THEORETICAL AND COMPUTED APPROXIMATE VALUES FOR OCCUPIED BANDWIDTH CCSDS 401 (4.2.1) B-1 Page 4.2.1-2 June 1993 5.0 TERMINOLOGY AND GLOSSARY Section 5 is included to assist the reader in interpreting the Recommendations found in Sections 2, 3, and 4 of this document. It does so by providing an explanation of key words, terms, phrases, abbreviations, and acronyms used in these Recommendations. Presently, there are two subsections: 5.1 Terminology 5.2 Glossary Section 5.1, Terminology, defines specific words, terms, and phrases which have special, but uniform, meanings throughout the text. Additionally, this section also includes quantitative values for some terms which are intended to assist the reader in interpreting the Recommendations. Section 5.2, Glossary, contains the full name for the abbreviations and acronyms used throughout this document. If a reader is uncertain as to the meaning any abbreviation or acronym, this Section should be consulted. Here, entries are arranged alphabetically. CCSDS 401 B-2 Page 5.0-1 September 1989 5.1 TERMINOLOGY Autotrack A system which causes earth station's antenna to automatically follow [track] a moving spacecraft. Bit Rate The baseband data rate exclusive of coding for either error correction or spectrum shaping purposes. Category A Missions Those missions whose altitude above the earth is less than, or equal to, 2 x 106 km. Category B Missions Those missions whose altitude above the earth is greater than 2 x 106 km. Dibit A group of two bits in 4- phase modulation, each possible dibit is encoded in the form of one of four unique phase shifts of the RF carrier. Loop Bandwidth The resultant phase locked bandwidth when the signal-to-noise ratio in the phase locked loop is 10 dB. Loop Threshold That signal level producing a signal- to-noise ratio of 10 dB in the phase locked loop's bandwidth. Libration Point A point of equal potential gravitational fields between two or more large bodies such as the Sun and the Earth. Link Design Control Table A set of tables used to display the operating parameters of a telecommunications link and to calculate the expected performance of that link. Link and Weather Not Combined With a Link Design Control Table, calculations are made assuming clear and dry weather conditions. Thereafter, the values obtained under such ideal conditions are adjusted using a correction factor representing the loss due to weather effects. Modulo-2 Addition Also called an "exclusive or", this term refers to the manner in which a pair of bits are added such that like bits result in a 0 and unlike bits produce a 1. Occupied Bandwidth (ITU/RR/147): "The width of a frequency band such that, below the lower and above the upper frequency limits, the mean powers emitted are each equal to a specified percentage á/2 of the total mean power of a given emission." [Unless otherwise specified by the CCIR for the appropriate class of emission, the value of á/2 should be taken as 0.5%."] CCSDS 401 (5.1) B-2 Page 5.1-1 September 1989 5.1 TERMINOLOGY (Continued) Radiocommunication Service (ITU/RR/RR1-3.1) "A Service . . . involving the transmission, emission and/or reception of radio waves for specific telecommunication purposes." Ranging Measurement A process for establishing, usually by a time delay measurement, the one-way distance between an earth station and a spacecraft. Symbol Rate The baseband bit rate following error correction coding but excluding any spectrum modification encoding. CCSDS 401 (5.1) B-2 Page 5.1-2 September 1989 5.2 GLOSSARY OF TERMS ACQ or Acq Acquisition AGC Automatic Gain Control AM Amplitude Modulation BER Bit Error Rate Bi-[...]-L Bi-Phase-Level modulation Bi-[...]-M Bi-Phase-Mark modulation Bi-[...]-S Bi-Phase-Space modulation BLO Phase Locked Loop Bandwidth BNSC British National Space Centre bps or b/s Bits Per Second BW Bandwidth Cat Category Category A Missions Those missions whose altitude above the Earth is less than, or equal to, 2 x 106 km Category B Missions Those missions whose altitude above the Earth is greater than 2 x 106 km CCIR International Radio Consultative Committee CCSDS Consultative Committee for Space Data Systems Cmd Telecommand CNES Centre National D'Etudes Spatiales COHER or Coh Coherent CRL Communications Research Laboratory CSA Canadian Space Agency dB Decibel(s) dBi Decibel(s) relative to an isotropically radiated signal dB/K Decibel(s) per degree Kelvin dBm Decibel(s) relative to one milliwatt dBW Decibel(s) relative to one Watt DCT Design Control Table [Link] deg Degree DLR Deutsche Forschungsanstalt fuer Luft-und Raumfahrt e. V. DNRZ Differential Non-Return to Zero CCSDS 401 (5.2) B-2 Page 5.2-1 September 1989 5.2 GLOSSARY OF TERMS (Continued) DOC/CRC Department of Communications, Communications Research Centre DRVID Differenced Range vs. Integrated Doppler Eb Energy per data bit Eb/N0 Energy per data bit to Noise ratio in a 1 Hz bandwidth EES Earth Exploration Service EIRP Equivalent Isotropically Radiated Power ELEV Elevation E/S Earth-to-Space ESA European Space Agency exp Exponent f or Freq Frequency fc RF carrier frequency fd Doppler frequency shift fsc Subcarrier frequency FM Frequency Modulation FN or Fn Footnote FSK Frequency Shift Keying GHz Gigahertz GND Ground GPS Global Positioning System G/T Antenna gain divided by the receiving system's noise temperature in degrees Kelvin (usually expressed in dB) h Hours Hz Hertz IEEE Institute of Electrical and Electronic Engineers IFRB International Frequency Registration Board INPE Instituto De Pesquisas Espaciais ISAS Institute of Space and Astronautical Science ISRO Indian Space Research Organization ITU International Telecommunication Union ITU/RR International Telecommunication Union Radio Regulations k Kilo (thousands) CCSDS 401 (5.2) B-2 Page 5.2-2 September 1989 5.2 GLOSSARY OF TERMS (Continued) K Degrees Kelvin kb/s Kilobits Per Second kHz Kilohertz km Kilometers Ku Ku-band (approximately 13 to 15 gigahertz) LCP Left Circular Polarization LIM or Lim Limitation(s) LIN or Lin Linear L.O. or LO Local Oscillator M Mega (million) m Meter(s) MAX or Max Maximum MHz Megahertz MIN or Min Minimum Mod Modulation n Nano ns Nanosecond(s) NASA National Aeronautics and Space Administration NASDA National Space Development Agency of Japan NOAA National Oceanic and Atmospheric Administration NRZ Non-Return to Zero NRZ-L Non-Return to Zero-Level NRZ-M Non-Return to Zero-Mark NRZ-S Non-Return to Zero-Space Pc Carrier power PCM Pulse Code Modulation PDF Probability Density Function PFD Power Flux Density Pk or pk Peak PLL Phase Locked Loop PM Phase Modulation CCSDS 401 (5.2) B-2 Page 5.2-3 September 1989 5.2 GLOSSARY OF TERMS (Continued) PN Pseudo Noise ppm Parts Per Million PRN Pseudo Random Noise PSK Phase Shift Keying PWR Power QPSK Quadra-Phase Shift Keying [modulation] OQPSK Offset Quadra-Phase Shift Keying [modulation] r Range Rad Radian RCP Right Circular Polarization RCVR or Rcvr Receiver Rec Receive REF or Ref Reference regen. regenerative resid. residual RF Radio Frequency RFI Radio Frequency Interference RLIN Rotatable Linear polarization rms Root Mean Square Rng Ranging RSS Root Sum Square S/C Spacecraft s or sec Second(s) S/E Space-to-Earth SEP Sun-Earth-Probe [angle] seq Sequential SFDU Standard Formatted Data Unit (CCSDS) SFCG Space Frequency Coordination Group SIG or sig Signal Sim Simultaneous SNR Signal-to-Noise Ratio CCSDS 401 (5.2) B-2 Page 5.2-4 September 1989 5.2 GLOSSARY OF TERMS (Continued) SP Split Phase SP-L Split Phase - Level sps or s/s Symbols Per Second SSC Swedish Space Corporation STA Station STAB Stability SUBCARR Subcarrier SYM or sym Symbol TBD To Be Determined TDRSS Tracking and Data Relay Satellite System Tlm Telemetry Trans or Tr Transmit TTC Tracking, Telemetry, and Command UTC Universal Time Coordinated VLBI Very Long Baseline Interferometry w/m2 Watts per square Meter X-band Approximately 8000 megahertz XMIT or Xmit Transmit yr Year [...] Delta (change or variation) [...] Phase [...] Micro CCSDS 401 (5.2) B-2 Page 5.2-5 September 1989