Author: AC Coordinator / AIUB/CODE Ultra Rapid IGS Orbit Combination - Week 1163 Day: 1 Hour: 00 (Apr 22, 2002) Contacts: R. Weber (rweber@luna.tuwien.ac.at), H. Bock (bock@aiub.unibe.ch), R. Dach (dach@aiub.unibe.ch) 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. REMARKS on IGS Ultra Rapid 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: 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 COU orbit solutions are excluded because they are not official Ultra rapid solutions. They are kept for statistics only. The following table lists the exclusions: Centre | PRN list -------+--------------- COU | ALL USU | 30 3. The following orbit solutions were rejected from the combination due to lack of redundancy, i.e. not enough centres providing a solution (=> Minimum number of centres: 3): Centre | PRN -------+----- GFU | 17 4. Starting on 02-Dec-2001 (GPS Week 1143, day 0, MJD 52245) all IGS products, including the IGS combined orbits, are based on the IGS realization of the ITRF2000 reference frame (IGS00). For more information see IGSMAIL #3605. _______________________________________________________________________________ Table 1: Daily transformation of each centre to the combined IGS orbit and clocks. WRMS - RMS weighted by the centres SP3 header accuracy codes. STA - Number of stations in the daily solutions. Units: meters, mas, ppb, nano-sec, nano-sec/day. Table 1.1163.1 GPS week: 1163 Day: 1 MJD: 52386.0 CENT STA| DX DY DZ RX RY RZ SCL RMS WRMS | TOFT TDRFT RMS --------|------------------------------------------------|--------------------- cou n/a|0.01 0.01-0.01 0.67 0.42 -0.03 -0.4 0.40 0.40 | 2.0 -2.7 20.39 emu 45 |0.00 0.00 0.00 0.01 -0.15 0.00 0.1 0.13 0.11 | 0.0 0.0 0.00 esu 30 |0.01 0.01 0.01 -0.19 0.37 0.34 -0.3 0.25 0.22 | 1462.1 34.1 2.83 gfu 32 |-.01 0.00 0.00 0.28 0.01 -1.45 -0.2 0.21 0.17 | -2.5 5.2 0.97 siu 38 |0.00 0.00 0.00 -0.02 0.05 1.21 -0.1 0.21 0.21 | 0.0 0.0 0.00 usu 27 |0.01-0.01-0.01 -0.07 -0.03 -0.34 0.1 0.37 0.18 | 215.6 -4.7 3.61 Table 2: Daily fit for each satellite and each centre resulting from weighted average combination. The last column gives the IGS resulting satellite accuracy measures found in the IGS SP3 header. Eclipsing satellites are flagged with and "E" beside the PRN number. "X" stands for excluded from combination but included in IGS orbit. "MEDI" stands for median of the centre's satellite RMS. Units: cm. Table 2.1163.1 GPS week: 1163 Day: 1 MJD: 52386.0 Weighted Average PRN | cou emu esu gfu siu usu IGU | ------|------------------------------| 1 | 16 11 13 15 11 18 7 | 3 | 9 14 21 17 9 26 9 | 4 | 11 11 13 16 17 21 8 | 5 | 131 19 21 14 24 51 14 | 6 | 13 11 16 15 9 29 8 | 7 | 15 8 16 14 12 10 6 | 8 | 14 12 15 11 9 18 6 | 9 | 16 6 17 13 7 8 5 | 10E | 34 20 20 14 37 18 12 | 11 | 17 9 22 23 20 16 9 | 13 | 10 9 30 15 6 25 9 | 14 | 34 18 20 12 20 22 9 | X15 | --- 12 --- 17 8 17 8 | 18E | 15 16 21 29 22 12 10 | 20E | 26 20 36 58 19 18 16 | X22 | 26 15 20 26 13 --- 11 | X23E | 30 10 --- 25 12 39 13 | 24 | 28 6 18 16 16 10 6 | 25 | 22 10 16 14 11 13 6 | 26 | 11 6 20 18 13 11 7 | 27 | 10 8 42 12 19 11 10 | 28E | 27 16 58 19 34 23 15 | 29 | 21 15 20 25 5 7 8 | 30E | 95 13 23 22 45 143 41 | 31 | 27 16 19 14 30 15 10 | ------|------------------------------| RMS | 40 13 25 21 21 37 | WRMS | 40 11 22 17 21 18 | MEDI | 19 12 20 16 13 18 | 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. Table 3.1163.0 GPS week: 1163 Day: 0 MJD: 52385.5 AC LOD AC LOD CENT FLAG | Xpole Ypole Xrt Yrt LOD | BIAS BIAS RMS ------------------------------------------------------------------------ cou xxxxx | -56 -67 -40 -50 -56 | -25 54 emu uuuuu | -2 -5 9 -20 13 | -25 38 esu* uuuuu | -41 13 20 5 -352 | 12 105 gfu uuuuu | -13 -18 -27 -30 30 | 9 31 siu uuxxx | 50 10 122 -13 79 | 83 169 usu uuuuu | -7 8 -1 67 -11 | -3 38 Table 3.1163.1 GPS week: 1163 Day: 1 MJD: 52386.5 AC LOD AC LOD CENT FLAG | Xpole Ypole Xrt Yrt LOD | BIAS BIAS RMS ------------------------------------------------------------------------ cou xxxxx | -64 -147 17 -8 34 | -25 54 emu uuuuu | 22 -58 31 18 -78 | -25 38 esu* uuuu- | -104 -77 -154 -82 --- | --- --- gfu uuuuu | -7 -78 30 12 120 | 9 31 siu uuxxx | 51 282 176 41 456 | 83 169 usu uuuuu | -9 -70 30 18 -103 | -3 38