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[IGSMAIL-5471]: IGS Ultra Combination (IGU): 1400 1 18 (Resubmission)
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IGS Electronic Mail 07 Nov 01:47:16 PST 2006 Message Number 5471
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Author: AC Coordinator / GFZ Potsdam
Ultra Rapid IGS Orbit Combination - Week 1400 Day: 1 Hour: 18 (Nov 06, 2006)
Contacts: G. Gendt (gendt @ gfz-potsdam.de),
Th. Nischan ( nisn @ gfz-potsdam.de)
COMBINATION STRATEGY:
---------------------
For a complete description of the combination strategy along with all tables
and statistics, please refer to the IGS Final Combination reports posted on
CDDIS within 13 days after the end of the GPS week.
PRODUCT FILES:
--------------
The Rapid Orbit files generated and uploaded into CDDIS @ NASA/GSFC are:
igu14001_18.sp3 IGR GPS ephemeris in SP3 format.
igu14001_18.erp Earth Rotation Parameters (ERP) and their rates as well as
Universal Time (UT1-UTC) and Length Of Day (LOD) associated
with IGS ephemerides.
igu14001_18.sum Combination summary report.
REMARKS concerning the IGU Orbit Combination:
---------------------------------------------
1. The following centre clock solutions, which provide broadcast and/or
predicted clock corrections, were excluded from the combination but kept
in the combination statistics:
-> Centre: GOU COU
2. The following orbit solutions were excluded from the combination because
they were biasing the weighted average. They were still used for statistics
computation unless all centres were excluded for the problem satellites in
which case they were simply eliminated from the combination and statistics.
The following table lists the exclusions:
Centre | PRN list
--------+---------------
COU | 29
GFU | 29
GOU | 13
SIU | 28 29
3. The following orbit solutions were excluded from the combination because
less than 3 ACs have submitted results for given satellite(s).
The following table lists the exclusions:
Centre | PRN list
--------+---------------
EMU | 29
4. Starting on 5-Nov-2006 (GPS Week 1400-0, MJD 54044) all IGS products,
including the IGS combined orbits, are based on the IGS realization of
the ITRF2005 reference frame (IGS05). For more information see IGSMAIL #5447.
At the same time the absolute antenna model is introduced (IGSMAIL #5272).
ORBIT COMBINATION AND EVALUATION STATISTICS:
--------------------------------------------
Table 1: Daily transformation of each centre to the combined IGU orbit
and clocks.
WRMS - RMS weighted by the centres SP3 header accuracy codes.
STA - Number of stations in the daily solutions.
Units: mas, ppb, meters, nano-sec, nano-sec/day.
Table 1.1400.1 GPS week: 1400 Day: 1 MJD: 54045.750
CENT STA| DX DY DZ RX RY RZ SCL RMS WRMS | TOFT TDRFT RMS
--------+------------------------------------------------+---------------------
cou 74| .00 -.00 -.01 -.08 -.02 -.60 -.2 .06 .03 | -.6 4.4 6.46
emu 49| .00 -.00 .00 -.01 -.06 .12 .1 .04 .03 | -.8 4.1 2.05
esu 40|-.00 -.00 .01 .30 .16 .23 .4 .08 .06 | .8 2.6 6.14
gfu 60|-.00 .00 -.01 .23 .01 .38 -.1 .06 .03 | -.1 3.6 1.82
gou 40| .00 .00 .00 -.21 .01 .42 -.2 .12 .05 | .0 -.0 48.43
siu 42|-.00 .01 -.01 -.65 .04 -.52 .6 .16 .11 | .0 .0 .0
Table 2: Daily fit for each satellite and each centre resulting from weighted
average combination.
The last column gives the IGU resulting satellite accuracy measures
found in the IGS SP3 header. Eclipsing satellites are flagged with
"E" (or "M" for moon) beside the PRN number. "X" stands for excluded
from RMS, WRMS and MEDI-combination statistics but included in IGU
Units: cm.
Table 2.1400.1 GPS week: 1400 Day: 1 MJD: 54045.750
Weighted Average
PRN | cou emu esu gfu gou siu IGU |
------+------------------------------+
1E | 4 6 6 8 5 12 3 |
2 | 2 2 4 2 3 6 1 |
3 | 3 5 5 4 5 15 2 |
4 | 3 1 7 4 4 9 2 |
5 | 4 3 5 2 3 10 2 |
6 | 3 3 6 4 3 11 2 |
7 | 3 3 6 2 6 12 2 |
8 | 3 4 6 2 4 17 2 |
9 | 4 3 5 2 5 9 2 |
10 | 3 2 5 3 5 12 2 |
11E | 4 3 5 7 8 26 3 |
13E | 25 11 28 15 55 16 10 |
14E | 3 5 6 17 6 7 4 |
X15 | 4 11 11 5 --- 8 4 |
16 | 3 4 5 4 6 9 2 |
17 | 4 4 8 3 5 8 2 |
18 | 2 2 6 3 2 15 2 |
19 | 4 4 5 5 11 17 3 |
20 | 3 2 6 3 5 9 2 |
21 | 3 2 6 2 2 12 2 |
22 | 3 4 6 3 3 7 2 |
23E | 6 4 6 12 9 6 3 |
24 | 3 3 6 3 4 9 2 |
25 | 2 3 5 2 3 8 2 |
26E | 4 4 5 6 3 17 3 |
27 | 3 2 5 2 4 9 2 |
28 | 4 4 6 6 13 57 3 |
X29E |---- --- --- --- --- --- 0 |
30 | 4 4 5 2 3 18 2 |
31 | 2 2 7 4 5 15 2 |
------+------------------------------+
RMS | 6 4 8 6 12 16 |
WRMS | 3 3 6 3 5 11 |
MEDI | 3 3 6 3 5 11 |
Table 3: Earth Orientation Parameters daily summary.
Daily Centre ERP, ERP Rates and LOD differences with respect to
IGU combined values.
Xpole,Xrt: x pole and x pole rate (10**-5")
Ypole,Yrt: y pole and y pole rate (10**-5"/day)
LOD: Length Of Day (us)
AC LOD BIAS: 21-day mean LOD bias with respect to Bulletin A (us)
AC LOD BIAS RMS: RMS of AC LOD BIAS (us)
FLAG: "u" (used), "x" (excluded), "-" (no submission)
for Xpole, Ypole, Xrt, Yrt and LOD
A star ("*") beside the AC name indicates that AC LOD values were
derived from AC UT1-UTC values.
Remark: COU submits ERP-products for 00 and 12 UT only,
for 06 and 18 UT extrapolations are used.
Table 3.1400.1 GPS week: 1400 Day: 1 MJD: 54045.250
AC LOD AC LOD
CENT FLAG | Xpole Ypole Xrt Yrt LOD | BIAS BIAS RMS
------------+------------------------------------+------------------
cou uuuuu | 6 5 4 -5 18 | -32 48
emu uuuuu | 4 -4 8 -7 32 | -3 29
esu* uuuxx | -25 -4 4 -115 261 | -33 163
gfu uuuuu | 5 -19 -12 7 -21 | 5 19
gou uuuuu | 1 10 -12 7 13 | -23 35
siu uuuux | -15 55 3 31 181 | -79 140
Table 3.1400.2 GPS week: 1400 Day: 2 MJD: 54046.250
AC LOD AC LOD
CENT FLAG | Xpole Ypole Xrt Yrt LOD | BIAS BIAS RMS
------------+------------------------------------+------------------
cou uuuuu | -3 0 5 6 112 | -32 48
emu uuuuu | 16 14 10 -1 -76 | -3 29
esu* uuuxx | -20 -111 7 -27 445 | -33 163
gfu uuuuu | -6 -4 -21 -17 10 | 5 19
gou uuuuu | 0 49 -12 8 23 | -23 35
siu uuuux | -1 94 11 7 365 | -79 140