GPS ORBIT ESTIMATION AND STATION COORDINATE IMPROVEMENT USING A 1992 IGS CAMPAIGN DATA SET

Abstract : Extensive orbit estimation and station coordinate improvement studies have been conducted using 3 weeks of Global Positioning System (GPS) pseudorange and carrier phase data from 34 globally distributed Stations collected during the 1992 International GPS Geodynamics Service Test Campaign (IGS 92). These stations consisted of the 10 Defense Mapping Agency (DMA) and Air Force GPS tracking sites and 24 IGS Rogue receiver sites. In all orbit fits that included the IGS Rogue receiver data, eight globally distributed fiducial sites were used to define the International Earth Rotation Service (IERS) Terrestrial Reference Frame 1991 (ITRF91). Orbits computed in the World Geodetic System 1984 (WGS 84) reference frame using the DMA and Air Force data were compared against orbits computed in ITRF91 using the IGS Rogue receiver data. The data sets were used simultaneously to derive GPS-realized WGS 84 coordinates for the 10 DMA and Air Force sites. These coordinates were evaluated using both the 3 weeks of data used in their derivation and an independent data span of 6 weeks from early 1993. The assumptions and results from all these studies are detailed in this report.