From: Weber Robert Message-Id: <200107111305.PAA07142@luna.tuwien.ac.at> Subject: [IGLOSMAIL-347] Wk 1111 IGX Orbits Report To: iglosmail@igscb.jpl.nasa.gov (IGLOS Mail Service) Date: Wed, 11 Jul 2001 15:05:58 METDST Cc: rweber@luna.tuwien.ac.at Sender: owner-iglosmail Precedence: bulk ****************************************************************************** IGLOS Electronic Mail 11 Jul 06:06:02 PDT 2001 Message Number 347 ****************************************************************************** Author: IGEX AC Coordinator IGX Orbit Combination - Week 1111 (Apr 22, 2001 - Apr 28, 2001) Contact: Robert Weber (rweber@luna.tuwien.ac.at) Elisabeth Fragner (efragner@luna.tuwien.ac.at) COMBINATION STRATEGY -------------------- Ephemeris are combined as weighted averages computed over all centres. Each centre and satellite is given a position weight computed from the centers absolute deviation to the unweighted average orbit after removing small differences in the reference frames. These weights were applied in a second iteration to estimate Helmert transformation parameters for each center. Finally the transformation parameters with respect to the combined solution and the RMS of the fit are reported in Tables 2.1111. The Earth Orientation Parameters (EOPs) are fixed to the values of the final IGS (GPS) combination. SOFTWARE: --------- The GPS long arc orbit analysis software used here for individual center ephemeris evaluation (Table 1) was developed by Beutler et al. at the Astronomical Institute of the University of Bern (AIUB). The weighted average (Tables 2. and 3.) software was developed by R.Weber according to Springer T., Beutler G., 1993, Towards an official IGS Orbit by combining the results of IGS processing centers. Proceedings of the IGS Workshop 1993, pp.242-249. Beutler G., Kouba J. and T. Springer, 1995, Combining the orbits of the IGS Analysis Centers, Bulletin Geodesique, 69, pp 200-222. Weber R., 2000, IGS Technical Report 1999 PRODUCTS GENERATED: ------------------- The combined IGEX-ephemerides are written to daily files in the SP3-format. The satellite accuracy codes in the header are based on the weighted rms. for each satellite. Note, that the result files contain all satellites that were analysed by at least one center. We refer to the 'REMARKS' section below, in case a satellite or center was excluded from the combination. The following naming convention is used for the result files: igx11110-6.sp3 IGEX Glonass ephemerides files for days 0-6 of GPS Week 1111 in the SP3 format. igx11117.sum Combination Report for GPS Week 1111. REMARKS concerning the IGEX Orbit Combination: 1. The satellite clock values in the combined orbit files are broadcast clock values. The value of 999999.999999 microseconds, according to the sp3 format convention, is used to indicate that no clock solution is available. 2. The following orbit solutions were excluded from the combination because they were biasing the weighted average (generally indicated by long arc RMS). Day | Centre | SAT list -----+--------+---------- | | 3. Until Wk 1020 the combined orbits refer to the ITRF96. Since Wk 1021 the combined orbits refer to the ITRF97. ORBIT COMBINATION AND EVALUATION STATISTICS: -------------------------------------------- Table 1 summarizes the statistics for a long-arc (seven days) analysis. It gives for each satellite the position rms. for each individual center and for the combined orbit. Table 2 contains the transformation parameters w.r.t. the combination for each center and each day (Tables 2.1111.0-6). Table 3 contains the daily RMS for each satellite and center w.r.t. the combination together with the computed satellite position RMS values for the combined orbits (Tables 3.1111.0-6). Table 1.1111 GPS week : 1111 MJD: 52021.0-52027.0 Long Arc Evaluation Satellite position RMS for the individual centers' orbits and for the combined orbit (IGX). "E" flags eclipsing satellites. "*" less than 7 days of data available. "--" not (continuously) available in center solution. Units: cm. ------------------------------ | SAT | BKG ESA MCC IGX | ------------------------------ | 1E | 7 18 9 8 | | 7E | 5 14 -- 8 | | 8E | 8 62 -- 34 | | 13 | 6 18 -- 10 | | 15 | -- 20 11 12 | | 17 | 7 10 -- 7 | | 18 | 9 16 -- 10 | | 24 | 6 12 7 7 | ------------------------------ |MEDIAN| 7 17 9 9 | ------------------------------ Table 2: Daily transformation parameters w.r.t. the combined orbit. Units: meters (DX, DY, DZ, RMS), mas (RX, RY, RZ), ppb (SCL). Table 2.1111.0 GPS week: 1111 Day: 0 MJD: 52021 |-----------------------------------------------------| | CENT STA| DX DY DZ RX RY RZ SCL RMS| |-----------------------------------------------------| | BKG 30| -.01 .01 -.06 -.22 .03 .21 -1.1 .15| | ESA 33| .01 -.01 .08 .21 -.05 -.84 1.8 .20| | MCC --| .00 .00 .10 .13 -.09 1.98 -2.2 .25| |-----------------------------------------------------| Table 2.1111.1 GPS week: 1111 Day: 1 MJD: 52022 |-----------------------------------------------------| | CENT STA| DX DY DZ RX RY RZ SCL RMS| |-----------------------------------------------------| | BKG 30| -.01 -.01 -.14 -.17 -.02 -.29 -2.0 .21| | ESA 33| .00 .01 .10 .32 .08 -.83 2.0 .18| | MCC --| .01 -.03 -.04 -.44 -.18 1.38 -1.2 .19| |-----------------------------------------------------| Table 2.1111.2 GPS week: 1111 Day: 2 MJD: 52023 |-----------------------------------------------------| | CENT STA| DX DY DZ RX RY RZ SCL RMS| |-----------------------------------------------------| | BKG 30| .00 -.01 -.14 -.30 -.01 -.60 -1.8 .24| | ESA 33| .00 .00 .09 .31 .27 -1.07 2.5 .19| | MCC --| .00 .00 -.03 -.10 -.29 1.77 -1.9 .11| |-----------------------------------------------------| Table 2.1111.3 GPS week: 1111 Day: 3 MJD: 52024 |-----------------------------------------------------| | CENT STA| DX DY DZ RX RY RZ SCL RMS| |-----------------------------------------------------| | BKG 30| .01 .00 -.05 -.33 -.12 -.77 -2.0 .22| | ESA 33| -.01 .00 .08 .37 .29 -.51 3.1 .19| | MCC --| .00 .00 -.06 -.19 -.21 1.45 -1.9 .09| |-----------------------------------------------------| Table 2.1111.4 GPS week: 1111 Day: 4 MJD: 52025 |-----------------------------------------------------| | CENT STA| DX DY DZ RX RY RZ SCL RMS| |-----------------------------------------------------| | BKG 30| .01 .01 -.11 -.42 -.15 -.09 -1.6 .19| | ESA 33| .00 .00 .11 .43 .19 -.14 2.6 .20| | MCC --| -.01 -.01 .02 .02 -.07 .22 -1.3 .07| |-----------------------------------------------------| Table 2.1111.5 GPS week: 1111 Day: 5 MJD: 52026 |-----------------------------------------------------| | CENT STA| DX DY DZ RX RY RZ SCL RMS| |-----------------------------------------------------| | BKG 30| -.01 .00 -.15 -.45 -.21 .88 -1.4 .22| | ESA 33| .00 .00 .18 .10 .37 .22 2.8 .21| | MCC --| .00 .00 -.02 .13 -.10 -.68 -1.4 .07| |-----------------------------------------------------| Table 2.1111.6 GPS week: 1111 Day: 6 MJD: 52027 |-----------------------------------------------------| | CENT STA| DX DY DZ RX RY RZ SCL RMS| |-----------------------------------------------------| | BKG 30| .00 .00 -.14 -.26 -.07 .92 -1.8 .19| | ESA 33| .01 .00 .12 .19 .07 -.17 2.5 .20| | MCC --| -.01 .00 .00 .07 -.04 -1.04 -1.1 .09| |-----------------------------------------------------| Table 3: Daily RMS difference w.r.t. combination per satellite and center. The IGX column gives the weighted RMS of the combination according to the accuracy codes in the SP3-file. "E" marks eclipsing satellites. Units: cm. Table 3.1111.0 GPS week: 1111 Day: 0 MJD: 52021 Weighted Average --------------------------- | SAT | BKG ESA MCC IGX | --------------------------- | 01 | 6 10 9 6 | | 07 | 6 7 -- 6 | | 08 | 24 31 -- 26 | | 13 | 7 9 -- 6 | | 15 | -- 22 30 26 | | 17 | 6 8 -- 6 | | 18 | 11 14 -- 13 | | 24 | 11 11 17 13 | --------------------------- |Median| 7 11 17 | --------------------------- Table 3.1111.1 GPS week: 1111 Day: 1 MJD: 52022 Weighted Average --------------------------- | SAT | BKG ESA MCC IGX | --------------------------- | 01 | 7 6 6 6 | | 07 | 8 7 -- 6 | | 08 | 40 36 -- 26 | | 13 | 8 7 -- 6 | | 15 | -- 16 16 13 | | 17 | 8 7 -- 6 | | 18 | 15 14 -- 13 | | 24 | 16 5 16 13 | --------------------------- |Median| 8 7 16 | --------------------------- Table 3.1111.2 GPS week: 1111 Day: 2 MJD: 52023 Weighted Average --------------------------- | SAT | BKG ESA MCC IGX | --------------------------- | 01 | 11 10 9 13 | | 07 | 9 7 -- 6 | | 08 | 43 36 -- 26 | | 13 | 9 8 -- 6 | | 15 | -- 6 4 6 | | 17 | 6 5 -- 6 | | 18 | 13 11 -- 13 | | 24 | 20 9 12 13 | --------------------------- |Median| 11 9 9 | --------------------------- Table 3.1111.3 GPS week: 1111 Day: 3 MJD: 52024 Weighted Average --------------------------- | SAT | BKG ESA MCC IGX | --------------------------- | 01 | 12 11 8 13 | | 07 | 7 6 -- 6 | | 08 | 47 42 -- 51 | | 13 | 7 6 -- 6 | | 15 | -- 9 4 6 | | 17 | 7 6 -- 6 | | 18 | 11 10 -- 13 | | 24 | 14 10 9 13 | --------------------------- |Median| 11 10 8 | --------------------------- Table 3.1111.4 GPS week: 1111 Day: 4 MJD: 52025 Weighted Average --------------------------- | SAT | BKG ESA MCC IGX | --------------------------- | 01 | 11 15 4 13 | | 07 | 3 3 -- 6 | | 08 | 37 37 -- 26 | | 13 | 8 8 -- 6 | | 15 | -- 15 6 13 | | 17 | 7 7 -- 6 | | 18 | 8 8 -- 6 | | 24 | 11 10 6 13 | --------------------------- |Median| 8 9 6 | --------------------------- Table 3.1111.5 GPS week: 1111 Day: 5 MJD: 52026 Weighted Average --------------------------- | SAT | BKG ESA MCC IGX | --------------------------- | 01 | 17 8 7 13 | | 07 | 8 8 -- 6 | | 08 | 36 36 -- 26 | | 13 | 6 6 -- 6 | | 15 | -- 13 4 13 | | 17 | 7 7 -- 6 | | 18 | 9 9 -- 6 | | 24 | 13 9 6 6 | --------------------------- |Median| 9 9 6 | --------------------------- Table 3.1111.6 GPS week: 1111 Day: 6 MJD: 52027 Weighted Average --------------------------- | SAT | BKG ESA MCC IGX | --------------------------- | 01 | 13 13 10 13 | | 07 | 5 5 -- 6 | | 08 | 28 28 -- 26 | | 13 | 8 8 -- 6 | | 15 | -- 10 5 6 | | 17 | 8 8 -- 6 | | 18 | 6 6 -- 6 | | 24 | 12 7 7 6 | --------------------------- |Median| 8 8 7 | --------------------------- End of Report: Week 1111 -- ___________________________________________________________________________ Robert Weber Tel: ++43-1-58801-12865 Department of Advanced Geodesy Fax: ++43-1-58801-12896 University of Technology, Vienna E-Mail: rweber@luna.tuwien.ac.at Gusshausstrasse 27-29 robert.weber@aiub.unibe.ch A-1040 Vienna, Austria ___________________________________________________________________________