Author: AC Coordinator / AIUB/CODE Ultra Rapid IGS Orbit Combination - Week 1149 Day: 1 Hour: 00 (Jan 14, 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 JPU | 21 JPU | 24 JPU | 29 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 -------+----- JPU | 15 EMU | 21 GFU | 23 SIU | 24 ESU | 29 GFU | 29 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 1.1149.1 GPS week: 1149 Day: 1 MJD: 52288.0 CENT STA| DX DY DZ RX RY RZ SCL RMS WRMS | TOFT TDRFT RMS --------|------------------------------------------------|--------------------- cou n/a|-.01 0.00-0.03 -0.25 -1.18 4.65 -0.2 0.52 0.52 | 0.6 0.5 17.80 emu 27 |0.00 0.00-0.01 -0.15 -0.17 0.02 -0.3 0.33 0.25 | 0.0 0.0 0.00 esu 29 |0.00 0.00 0.03 -0.23 -0.16 0.27 0.4 0.29 0.26 | 1917.0 16.6 3.02 gfu 28 |0.00 0.00 0.00 0.50 0.32 -0.36 0.0 0.20 0.17 | -1.2 5.0 2.04 jpu 20 |-.03-0.01-0.01 0.04 -0.18 0.42 0.0 0.93 0.92 | -1.1 3.3 1.75 siu 33 |0.00 0.00 0.00 -0.82 -0.07 0.39 0.2 0.65 0.65 | 0.0 0.0 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 2.1149.1 GPS week: 1149 Day: 1 MJD: 52288.0 Weighted Average PRN | cou emu esu gfu jpu siu IGU | ------|------------------------------| X1E | 31 16 --- 8 66 30 14 | X2 | 15 14 --- 10 71 23 14 | 3 | 27 12 25 6 69 41 13 | 4E | 40 36 15 8 50 28 12 | 5 | 139 48 12 12 46 59 17 | 6 | 73 14 35 14 77 91 21 | 7 | 52 6 16 9 115 45 17 | X8 | 19 11 --- 26 223 34 38 | 9 | 38 22 17 8 132 12 18 | X10 | 33 46 19 8 --- 128 30 | 11E | 22 17 52 10 99 35 19 | 13E | 67 14 23 11 96 107 23 | X14E | >>> --- 34 48 198 --- 51 | X17 | 50 54 --- 16 137 16 28 | 18 | 46 24 30 8 38 52 14 | 20 | 26 34 19 7 37 56 14 | 22 | 28 63 36 25 111 76 27 | 25 | 54 82 57 41 44 82 31 | 26E | 22 20 20 54 96 138 32 | 27 | 20 8 13 10 37 48 10 | 28 | 20 10 19 13 126 19 17 | 30 | 35 8 32 7 84 34 14 | 31 | 14 12 23 17 178 22 23 | ------|------------------------------| RMS | 52 33 29 20 93 65 | WRMS | 52 25 26 17 92 65 | MEDI | 33 17 23 10 90 43 | 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 3.1149.0 GPS week: 1149 Day: 0 MJD: 52287.5 AC LOD AC LOD CENT FLAG | Xpole Ypole Xrt Yrt LOD | BIAS BIAS RMS ------------------------------------------------------------------------ cou xxxxx | 110 15 154 43 -253 | 5 115 emu uuuuu | 15 15 53 29 -60 | 14 36 esu* uuuuu | -22 1 12 37 -90 | 5 51 gfu uuuuu | -2 -12 -55 -39 -1 | 11 31 jpu uuuuu | -8 -24 120 9 -253 | -63 405 siu uuxxu | 25 22 94 167 143 | -27 42 Table 3.1149.1 GPS week: 1149 Day: 1 MJD: 52288.5 AC LOD AC LOD CENT FLAG | Xpole Ypole Xrt Yrt LOD | BIAS BIAS RMS ------------------------------------------------------------------------ cou xxxxx | 217 63 52 39 -303 | 5 115 emu uuuuu | 23 44 -45 15 -16 | 14 36 esu* uuuu- | 145 57 315 59 --- | --- --- gfu uuuuu | -105 -46 -158 -44 -51 | 11 31 jpu uuuuu | 62 -9 13 6 -291 | -63 405 siu uuxxu | -2 -33 8 214 116 | -27 42