to develop and
operate the frequency and
time services essential for
synchronizing important
industrial/commercial operations
and supporting trade
and commerce.
INTENDED OUTCOME AND
BACKGROUND
The Division provides continuous, reliable,
time and frequency signals in a
wide variety of formats and accuracies to
meet diverse needs of U.S. industry,
trade, science, and the general public.
NIST time and frequency information
is distributed over the Internet, by radio
broadcasts, over telephone lines, and
through satellites to serve customers in
finance, telecommunications, science,
transportation, radio/TV broadcasting,
and other businesses--and as a reliable
and convenient source of official U.S.
time for the general public.
NIST radio stations WWV in
Ft. Collins, Colorado and WWVH in
Kauai, Hawaii broadcast shortwave
radio signals containing a rich variety of
time and frequency information, in the
form of verbal announcements, tones,
and digital time codes. NIST radio station
WWVB in Ft. Collins, Colorado
broadcasts a low-frequency (60 kHz)
digital time code that automatically sets
consumer timepieces to official U.S.
time and date, automatically correcting
for daylight saving time, leap years, and leap seconds.
NIST's most heavily used service is the
Internet Time Service (ITS), automatically
setting clocks in computers and
networked devices to NIST time. The
Division also provides the modem-based
Automated Computer Time Service
(ACTS) to set computer and network
device time. Many ACTS customers
need the security of a direct connection
to NIST to ensure that the time is legally
traceable to NIST and is auditable.
For example, the National Association
of Securities Dealers (NASD) requires
its 600,000 members to time-stamp
many billions of dollars of electronic
transactions each business day against NIST time.
The Frequency Measurement and
Analysis Service (FMAS) serves industrial
and research customers who need
tight traceability to NIST frequency
standards. FMAS customers receive continuous,
real-time NIST traceability
through a highly automated system
remotely monitored by NIST, receiving
NIST frequency standards by comparison
to GPS broadcasts. The most
demanding customer needs are met
through the Global Time Service, which
uses GPS common-view time transfer to
deliver to the user's site a timing reference
very close in accuracy to the NIST time scale.
To enhance U.S. expertise in this field,
the Division offers a variety of training
courses. A 3½ day metrology seminar is
offered annually, a new 3 day seminar
has been initiated for entry-level time
and frequency metrologists, and we
cosponsor an annual workshop on synchronization
in telecommunications systems. NIST staff members also
teach courses at conferences.
Accomplishments
NIST Internet Time Service (ITS)
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Figure 3. Growth in use of the NIST Internet
Time Service. |
Fourteen ITS servers at eleven locations
across the Nation respond to about
1½ billion requests per day (as of summer
2004) for setting computer and
network clocks to NIST time, automatically.
(See Fig. 3.) The Division website
provides free client software, complete
source code, and complete instructions
(about 100,000 downloads per month).
Automatic synchronization to ITS is
now a capability of the most popular
computer operating systems, including
Windows XP, Mac OS, and many
commercial versions of Linux.
The Division continually updates the
servers, software, and network infrastructure,
working with the NIST networking
group, to ensure continued
provision of ITS in light of increasing demands.
A number of companies have partnered
with NIST to add traceability and
auditability to ITS for timestamping
electronic documents and financial
transactions. These applications are in
rather limited use now, but are growing
rapidly. It is likely that they will become
part of the national information infrastructure.
For example, the U.S. Postal
Service Electronic Postmark program
places a secure, auditable timestamp
on electronic documents referenced to
NIST time, and stores these documents
on secure servers for parties in a transaction
to examine and exchange as legal documents.
NIST Radio Stations WWV,
WWVH, and WWVB
The Division continues to upgrade the
radio stations as part of a long-term
modernization plan. Progress includes
continuing improvements to WWV and
WWVB transmitters and broadcast systems,
including systems to ensure automatic
recovery from power failures or
loss of primary transmitters when station
staff are not present; continuing
replacement of WWVH metal antenna
towers, subject to corrosion from sea
salt, with fiberglass towers hinged to
permit bending the tower to the ground
for easy and safe maintenance; and
upgrading insulators in the guy wires
supporting the eight 122 meter
(400 foot) towers for the WWVB antennas (Fig. 4).
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Figure 4. Growth in use of the NIST Internet Time Service. |
More than 50 manufacturers produce
WWVB-controlled timepieces, with several
million new units sold each year.
With growing sales, both manufacturers
and consumers want to know that
WWVB signal strength is sufficiently
strong across the Nation to ensure good
reception. We designed a monitor system
to measure received power from
WWVB broadcasts, and several of these
systems were constructed on contract.
We plan to place them at strategic locations
around the U.S. Through an
Internet connection, each will continuously
report back the WWVB signal
strength to the Division. The results will
be displayed on a publicly available website,
along with archives of all signal strength records.
We have been actively consulting with
WWVB-controlled timepiece manufacturers
to improve their product performance.
The monitoring data will help
manufacturers set performance specifications
for real-world signal strengths.
Consumers can also consult the website
to determine if problems with their
timepieces result from inadequate
WWVB signals or, as is almost always
the case, from problems with the timepiece itself.
The Division is publishing a "Recommended Practices for
Manufacturers and Consumers of WWVB Radio Controlled Clocks"
guide, developed in consultation with
manufacturers and enthusiast user
groups, which suggests practices to
ensure optimal timepiece performance.
First strategic focus |
Second strategic focus |
Third strategic focus |
Fourth strategic focus
"Technical Activities 2004" - Table of Contents |
