Author: AC Coordinator / AIUB/CODE Ultra Rapid IGS Orbit Combination - Week 1094 Day: 3 Hour: 12 (Dec 27, 2000) Contacts: R. Weber (rweber@terra.tuwien.ac.at), T.A. Springer (springer@aiub.unibe.ch), 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 11 days after the end of the GPS week. REMARKS on IGS Ultra Rapid Orbit Combination: 1. The following non-Ultra-rapid orbits were excluded from the combination but kept for 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 following table lists the exclusions: Centre | PRN list -------+--------------- SIU | ALL (high Transformation - See Table 1) 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 | 3 GFU | 23 4. Starting on 04-June-2000 (GPS Week 1065, day 0, MJD 51699) all IGS products, including the IGS combined orbits, are based on the IGS realization of the ITRF97 reference frame (IGS97). For more information see IGSMAILs #2899 and #2904. _______________________________________________________________________________ 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 1.1094.3 GPS week: 1094 Day: 3 MJD: 51905.5 CENT STA| DX DY DZ RX RY RZ SCL RMS WRMS | TOFT TDRFT RMS --------|------------------------------------------------|--------------------- cou 84 |0.01 0.02-0.02 0.26 0.25 -0.32 -0.6 0.59 0.31 | 0.2 0.9 13.18 emu 38 |0.00 0.00 0.02 -0.03 -0.08 0.01 0.0 0.21 0.16 | 0.0 0.0 0.00 gfu 30 |0.00 0.00-0.01 0.05 0.12 0.11 0.0 0.23 0.19 | 0.0 0.0 0.00 siu 38 |0.00 0.00 0.04 2.22 -1.71 5.12 -3.0 1.85 2.14 | 0.0 0.0 0.00 usu 25 |0.00-0.01-0.01 -0.04 -0.02 -0.42 0.2 0.39 0.29 | 2380.0 11.7 0.00 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 2.1094.3 GPS week: 1094 Day: 3 MJD: 51905.5 Weighted Average PRN | cou emu gfu siu usu IGU | ------|--------------------------| 1 | 108 24 36 251 36 22 | X2 | 12 23 22 288 --- 23 | 4 | 15 24 19 51 12 14 | X5 | 34 7 6 50 --- 7 | 6E | 70 19 15 289 12 11 | 7E | 39 20 25 184 73 29 | 8 | 19 15 8 224 37 15 | 9 | 21 17 7 161 17 10 | 10 | 10 10 8 248 10 7 | 11 | 13 18 12 189 16 11 | 13 | 74 25 22 217 61 25 | 14 | 14 22 7 311 26 13 | 15 | 22 6 8 214 11 6 | 17 | 108 30 33 161 102 40 | 19 | 44 5 8 251 17 7 | 20 | 20 14 7 70 15 8 | 21 | 89 20 40 148 46 25 | 22 | 13 8 13 73 12 8 | X24 | 398 --- 28 138 47 36 | 25 | 5 18 16 --- 10 11 | 26 | 22 14 29 --- 65 26 | 27 | 25 12 4 265 22 9 | 28 | 16 21 9 85 21 12 | X29 | 40 21 20 --- --- 20 | 30 | 62 16 15 38 21 12 | 31E | 155 50 61 88 32 36 | ------|--------------------------| RMS | 59 21 23 185 39 | WRMS | 31 16 19 214 29 | MEDI | 24 18 15 184 21 | 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 3.1094.3 GPS week: 1094 Day: 3 MJD: 51905.0 AC LOD AC LOD CENT FLAG | Xpole Ypole Xrt Yrt LOD | BIAS BIAS RMS ------------------------------------------------------------------------ cou xxxxx | -17 -57 -19 -30 -46 | -4 92 emu uuuuu | 4 0 7 16 92 | -64 76 gfu uuuuu | -6 -44 -3 -13 -50 | -1 60 siu xxxxx | -532 354 242 159 -65 | 0 93 usu uuuuu | 3 73 -7 -4 -15 | 1 82 Table 3.1094.4 GPS week: 1094 Day: 4 MJD: 51906.0 AC LOD AC LOD CENT FLAG | Xpole Ypole Xrt Yrt LOD | BIAS BIAS RMS ------------------------------------------------------------------------ cou xxxxx | -38 -85 -19 -44 17 | -4 92 emu uuuuu | 5 29 4 1 78 | -64 76 gfu uuuuu | -18 -19 -8 -4 -55 | -1 60 siu -xxxx | --- 536 37 178 -23 | 0 93 usu uuuuu | 22 -14 7 4 11 | 1 82