Experience Using GPS For Orbit Determination of a Geosynchronous Satellite

There has long been speculation in the GPS user community about the viability of GPS-based satellite navigation from orbits above the GPS constellation. This paper addresses the speculation by describing the experience of a restricted United States satellite program that has routinely been using GPS pseudorange data for orbit determination at geosynchronous altitude for several years. Included is: a discussion of the design issues unique to the geosynchronous application, a description of the implementation, a discussion of the operational results and some observations about accuracy. In addition, actual received signal strength data are presented to illustrate the L1 transmit antenna pattern difference between the Block II-A and Block II-R GPS vehicles.