Author: AC Coordinator / GFZ Potsdam Rapid IGS Orbit Combination - Week 1255 Day: 1 (Jan 26, 2004) 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. 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 IGU Ultra rapid 1-day prediction orbits/clocks were excluded from the combination but kept for statistics: -> Centre: IGU 3. The following centre clock solutions, which provide broadcast clock corrections, were excluded from the combination but kept in the combination statistics: -> Centre: NGS 4. The following clock solutions were excluded from the combination because they were biasing the combined clock solutions. Centre | PRN/STA list -------+--------------- IGA | ALL COD | KIT3 NYA1 ESA | 29 ALGO ASC1 BOGT HOB2 MAS1 MDO1 NYAL RIOG TIDB YELL USN | PIMO THU3 TIDB 5. Because of a maneuver, some satellites were excluded from the Rapid combination. The following table lists the maneuvered satellites: PRN | Date | Ref. NANU ----+------------+----------- 27 | 2004_01_26 | 2004009 (Predicted) 6. 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 -------+--------------- IGA | ALL 7. 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. 8. Starting on 5-Nov-2000 (GPS Week 1087, day 0; mjd=51853) all IGS clock products are based on the new clock combination scheme which uses the the clock RINEX files as input if available, otherwise SP3 clocks are used. The navigation solution is still based on the SP3 clocks but this will soon adopt the clock RINEX files as well. 9. Starting on 29-Nov-1998 (GPS Week 986, day 0; mjd=51146) all IGS clock products reflect the use of the following antenna phase center offsets (satellite fixed reference frame): Block II/IIA: 0.279 0.000 1.023 X, Y, Z in meters Block IIR : 0.000 0.000 0.000 X, Y, Z in meters _______________________________________________________________________________ Table 1: Daily transformation of each centre to the combined IGR 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. iga : igu for the 24h data part Table 1.1255.1 GPS week: 1255 Day: 1 MJD: 53030.0 CENT STA| DX DY DZ RX RY RZ SCL RMS WRMS | TOFT TDRFT RMS --------|------------------------------------------------|--------------------- brd n/a|-.03 0.00-0.04 -1.73 -2.45 -0.53 12.0 1.51 1.51 | -0.1 0.1 3.60 cod 119|0.00 0.01 0.00 0.05 0.03 -0.03 -0.2 0.02 0.02 | 0.1 -0.2 0.05 emr 33 |0.00 0.00-0.01 0.11 0.01 -0.02 0.5 0.04 0.04 | 960.3 23.7 0.04 esa 45 |0.00 0.00-0.01 -0.13 0.30 -0.04 0.3 0.08 0.07 | 0.1 -1.3 0.09 gfz 49 |0.00 0.00 0.00 0.08 0.00 0.04 -0.2 0.02 0.02 | 0.1 0.4 0.04 iga n/a|0.00 0.00 0.00 0.01 -0.02 0.06 0.0 0.02 0.02 | -0.1 0.1 0.09 igu n/a|0.00 0.00 0.01 0.11 -0.57 0.04 -0.3 0.16 0.08 | -0.1 0.1 3.10 jpl 42 |0.00 0.00 0.00 -0.03 -0.18 0.07 0.3 0.06 0.06 | -4.4 -1.2 0.04 ngs 70 |0.01-0.01 0.00 -0.07 0.11 -0.06 -0.3 0.07 0.05 | -0.1 0.1 3.50 sio 36 |0.00 0.00 0.01 -0.37 -0.22 0.02 -0.2 0.07 0.06 | 0.0 0.0 0.00 usn 34 |0.00 0.00-0.01 -0.04 0.01 0.02 0.3 0.03 0.03 | 961.6 11.8 0.06 Table 2: Daily fit for each satellite and each centre resulting from weighted average combination. The last column gives the IGR resulting satellite accuracy measures found in the IGR SP3 header. Eclipsing satellites are flagged with and "E" beside the PRN number. "X" stands for excluded from RMS, WRMS and MEDIan combination statistics but included in IGR orbit. "MEDI" stands for median of the centre's satellite RMS. Units: cm. Table 2.1255.1 GPS week: 1255 Day: 1 MJD: 53030.000 Weighted Average PRN | brd cod emr esa gfz iga igu jpl ngs sio usn IGR | ------|--------------------------------------------------| 1 | 231 1 3 7 2 2 7 3 4 4 4 1 | 2 | 142 1 4 6 1 1 6 3 6 4 2 1 | 3 | 88 1 4 8 2 1 5 2 6 8 2 1 | 4 | 111 2 2 5 2 2 3 3 6 6 2 1 | 5 | 82 2 4 9 2 1 3 4 5 5 2 1 | 6 | 187 2 5 6 2 2 3 3 6 8 3 1 | 7 | 100 1 3 9 1 2 3 8 7 4 2 1 | 8E | 325 2 5 17 3 2 38 5 9 4 4 2 | 9E | 154 3 5 9 3 2 6 8 12 2 4 2 | 10 | 174 2 2 4 2 2 6 3 6 5 4 1 | 11 | 90 3 4 10 3 2 3 8 8 5 4 2 | 13 | 117 2 4 5 2 2 6 6 7 6 3 1 | 14 | 71 2 4 6 2 2 4 9 8 7 3 2 | 15 | 183 1 5 8 1 1 4 3 6 5 2 1 | 16 | 95 2 3 7 2 1 2 4 6 4 2 1 | 17E | 136 2 3 13 2 4 20 5 7 4 3 1 | 18 | 78 2 6 10 3 3 11 7 7 3 2 2 | 20 | 55 2 4 4 1 2 4 6 5 3 3 1 | 21 | 121 2 6 7 2 2 2 7 5 5 2 2 | 22 | 121 2 7 8 3 3 14 10 6 22 3 3 | 23 | 147 3 3 5 3 3 10 8 8 10 3 2 | 24 | 339 2 2 6 1 2 10 5 4 5 2 1 | 25E | 129 2 4 5 3 2 19 5 9 4 4 1 | 26 | 87 2 3 7 2 2 4 2 7 4 2 1 | 28 | 156 3 3 7 2 2 6 4 10 10 3 2 | 29 | 139 3 3 15 3 6 60 5 5 4 5 2 | 30 | 76 1 4 6 2 2 7 4 4 3 3 1 | 31 | 42 1 2 10 2 2 12 4 6 5 2 1 | ------|--------------------------------------------------| RMS | 152 2 4 8 2 2 16 6 7 7 3 | WRMS | 152 2 4 7 2 2 8 6 5 6 3 | MEDI | 121 2 4 7 2 2 6 5 6 5 3 | 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 estimated 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 3.1255.1 GPS week: 1255 Day: 1 MJD: 53030.0 CENT| CLK EPO | BRUS | TOW2 | WILL | ----|----------|----------------|----------------|----------------| cod | cod 2784 | 1 1 3 | 1 2 3 | 1 1 3 | emr | emr 2676 | 2 4 6 | 1 2 4 | 2 2 5 | esa | esa 2765 | 1 2 5 | 1 2 4 | 1 2 5 | gfz | gfz 2763 | 2 2 5 | 2 2 7 | 2 2 4 | igr | igr 2688 | 2 2 4 | 1 2 4 | 2 2 5 | jpl | jpl 2756 | 2 3 6 | 2 3 5 | 2 2 6 | usn | usn 2763 | 3 3 4 | 2 2 4 | 2 3 5 | Table 4: Earth Orientation Parameters daily summary. Daily Centre ERP, ERP Rates and LOD differences with respect to IGR 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 4.1255.1 GPS week: 1255 Day: 1 MJD: 53030.5 AC LOD AC LOD CENT FLAG | Xpole Ypole Xrt Yrt LOD | BIAS BIAS RMS ------------------------------------------------------------------------ cod uuuuu | -5 -5 10 -14 3 | -2 17 emr uuuuu | 0 -11 -16 -23 -9 | 22 40 esa uuuuu | -40 5 -24 22 29 | 30 34 gfz uuuuu | 2 -3 -8 7 -5 | 0 21 iga xxxxx | -1 4 5 4 -2 | 11 22 igu xxxxx | 60 -6 68 26 28 | -20 50 jpl uuuuu | 26 13 -14 -3 18 | 4 21 ngs uuuuu | -10 12 -23 -5 -25 | -1 26 sio uuuuu | 14 15 45 55 -32 | 11 34 usn uuuuu | 0 4 7 6 13 | 37 47