Citation
Abstract
High precision orbit determination of Global Positioning System (GPS) satellites is a key requirement for GPS-based precise geodetic measurements and precise low-farth orbiter tracking, which are currently being studied at the Jet Propulsion Laboratory (JPL). Different strategies for orbit determination have been explored at JPL with data from a 1985 GPS field experiment. The most successful strategy uses multi-day arcs for orbit determination and includes fine tuning of spacecraft solar pressure coefficients and station zenith tropospheric delays using the GPS data. Average rms orbit repeatability values for five of the GPS satellites are 1.0, 1.2, and 1.7m in altitude, cross-track, and down-track components when two independent five-day fits are compared. Orbit predictions up to 24 hours outside the multi-day arcs agree within 4m of independent solutions obtained with well-tracked satellites in the prediction interval, Baseline repeatability improves with multi-day as compared to single-day arc orbit solutions. When tropospheric delay fluctuations are modeled with process nvise, significant additional improvement in baseline repeatability is achieved. For a 246 km baseline, with six-day are solutions for GPS orbits, baseline repeatability is 2 parts in 108 (0.4-0.6 cm) for east, north, and length components and 8 parts in 108 for the vertical component. For 1314 and 1509 km baselines with the same orbits, baseline repeatability is 2 parts in 108 for the north components (2-3 cm) and 4 parts in 10° or better for east, length, and vertical components.
Details
- Volume
- 42-91
- Published
- November 15, 1987
- Pages
- 1–22
- File Size
- 1.2 MB