REAL-TIME, AUTONOMOUS, PRECISE ORBIT DETERMINATION USING GPS

David B. Goldstein, George H. Born, and Penina Axelrad

Peer Reviewed

Abstract:	The desire for autonomously generated, rapidly available, and highly accurate satellite ephemeris is growing with the proliferation of constellations of satellites and the cost and overhead of ground tracking resources. Autonomous orbit determination (OD) based on observations from spaceborne GPS receivers is done on the ground in a postprocessing mode or in real time on board satellites. In an effort to estimate precise satellite ephemerides in real time on board a satellite, the Goddard Space Flight Center (GSFC) created the GPS Enhanced OD Experiment (GEODE) flight navigation software. This paper presents a characterization of GEODE performance and illustrates enhancements to GEODE designed to increase on-board, real-time total position accuracy and precision without increasing computational burden. Specifically, an alternative gravity field representation, a relative ionospheric error correction based on code-carrier divergence, and a dynamic model adjustment for filter tuning were investigated. Processing of flight data from TOPEX/Poseidon (T/P) indicates that total position accuracy at the meter level is possible in real time with the proposed enhancements to GEODE.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 48, Number 3
Pages:	155 - 168
Cite this article:	Goldstein, David B., Born, George H., Axelrad, Penina, "REAL-TIME, AUTONOMOUS, PRECISE ORBIT DETERMINATION USING GPS", NAVIGATION: Journal of The Institute of Navigation, Vol. 48, No. 3, Fall 2001, pp. 155-168.
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