Author: AC Coordinator / NRCan GSDivision Rapid IGS Orbit Combination - Week 0914 Day: 4 (Jul 17, 1997) Contacts: J. Kouba (kouba@geod.emr.ca), Y. Mireault (mireault@geod.emr.ca) 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 Rapid Orbit Combination: 1. Broadcast ("brd") orbits/clocks are included in the combination for statistics only. However broadcast clock corrections are used for clock alignment to GPS time and centre clock weight determination purposes. 2. The following IGR 2-day prediction orbits/clocks were excluded from the combination but kept for statistics: -> Centre: IGP 3. The following centre clock solutions, which provide broadcast clock corrections, were excluded from the combination but kept in the combination statistics: -> Centre: NGS COD 4. Centre clock weights were determined using the following non-SA satellites: PRN15. 5. Starting on June 30, 1996 all IGS products, including the IGS combined orbits, are based on ITRF94. 6. Starting with GPS wk 0895, IGS LOD combinations were implemented in the Rapid IGS solutions. AC LOD biases with respect to Bulletin A are estimated using Bulletin A most recent 3 weeks (21 days), i.e. up to 5 days prior to the last non-predicted day of Bulletin A. AC LOD biases are removed and the new AC bias-free LODs are used to compute a weighted IGS LOD which in turn is used to integrate UT1-UTC. The starting UT1-UTC value is chosen as Bulletin A fifth day prior to its last non-predicted day. _______________________________________________________________________________ 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 1.0914.4 GPS week: 0914 Day: 4 MJD: 50646.0 CENT STA| DX DY DZ RX RY RZ SCL RMS WRMS | TOFT TDRFT RMS --------|------------------------------------------------|--------------------- brd n/a| .08 -.05 .18 5.25 -8.39 -.19 -2.8 2.07 2.07 | 2.5 -6.2 81.6 cod 77 |-.01 .02 -.01 -.27 -.03 .62 .0 .11 .10 | 2.6 -6.4 81.7 emr 22 |-.01 .00 -.01 .59 .23 .40 -.1 .08 .08 | 183.0 10.7 .5 esa 57 | .02 .03 .00 -.09 -.52 .35 .1 .10 .09 | -4.6 -63.1 1.4 gfz 31 |-.01 -.03 .01 -.16 -.32 -.37 -.1 .09 .09 | 1444.5 76.0 .5 igp n/a|-.01 .01 -.05 -.74 1.41 1.26 -.1 9.29 1.90 | 2.0 -9.0 89.1 jpl 21 | .00 .02 .00 -.26 .02 .32 .4 .08 .08 | -28.4 .2 .5 ngs 51 | .01 -.03 -.01 -.08 .12 .82 -.6 .19 .19 | 2.6 -6.3 81.5 sio 50 | .00 .02 -.01 -.22 .22 -2.16 -.2 .10 .10 | .0 .0 .0 usn 25 | .00 -.05 .01 .49 .27 .60 .2 .11 .11 | 1444.1 76.1 .5 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. "MEDI" stands for median of the centre's satellite RMS. Units: cm. Table 2.0914.4 GPS week: 0914 Day: 4 MJD: 50646.0 Weighted Average PRN | brd cod emr esa gfz igp jpl ngs sio usn IGS | ------|----------------------------------------------| 1 | 135 8 7 11 10 53 6 24 9 11 4 | 2 | 102 9 8 6 10 20 13 16 6 11 4 | 3E | 154 16 7 6 11 161 9 21 12 9 4 | 4 | 291 11 7 8 7 69 6 22 7 8 3 | 5 | 149 16 5 11 14 112 7 12 7 13 4 | 6 | 345 10 8 10 7 18 6 17 7 14 4 | 7E | 257 15 12 13 9 51 8 18 6 11 4 | 9 | 74 14 7 8 5 52 8 12 9 6 3 | 10E | 213 7 10 11 8 27 7 48 9 10 5 | 14E | 307 7 8 10 6 >>> 8 12 21 15 4 | 15 | 99 11 5 9 6 31 13 17 14 9 4 | 16E | 298 11 10 17 13 --- 7 12 8 13 4 | 17 | 84 7 7 4 6 42 7 17 6 6 3 | 18 | 389 10 10 18 12 221 9 16 14 11 5 | 19 | 73 8 4 8 4 60 6 7 9 8 3 | 21E | 263 11 9 13 11 34 12 16 10 21 5 | 22 | 190 6 10 6 6 29 7 16 11 14 4 | 23E | 231 10 8 8 7 600 7 15 13 13 4 | 24 | 236 9 6 11 6 95 6 21 7 8 3 | 25 | 164 9 6 5 7 14 6 15 12 8 3 | 26 | 184 15 7 8 13 43 7 12 8 8 4 | 27 | 143 7 10 5 7 9 7 20 9 8 3 | 29 | 81 11 8 8 7 129 7 19 12 9 4 | 30 | 90 7 9 9 6 62 10 8 9 12 3 | 31E | 86 16 6 8 10 23 7 12 10 12 4 | ------|----------------------------------------------| RMS | 207 11 8 10 9 929 8 19 10 11 | WRMS | 207 10 8 9 9 190 8 19 10 11 | MEDI | 164 10 8 8 7 52 7 16 9 11 | Table 3: Daily Precise Navigation Summary using the corresponding Centre orbit positions and satellite clock corrections at 15 min intervals. Each line gives the daily station RMS w.r.t. the initial coordinates for the Latitude, Longitude and Height components. CLK - Satellite clocks used. EPO - Number of satellite clock epochs available for that day. Units: centimetres. Table 3.0914.4 GPS week: 0914 Day: 4 MJD: 50646.0 CENT| CLK EPO | USUD | WILL | ----|----------|----------------|----------------| emr | emr 2377 | 30 19 64 | 20 23 49 | esa | esa 2129 | 47 54 127 | 26 28 53 | gfz | gfz 1189 | 25 12 57 | 19 17 41 | igr | igr 2398 | 31 22 70 | 21 22 49 | jpl | jpl 2367 | 28 18 65 | 21 23 50 | usn | usn 2374 | 28 18 70 | 22 22 51 |