Advantage of Medium Earth Orbit for a GPS Augmentation System

Dennis M. Galvin

Abstract:	Satellite orbits for augmentation of the Global Positioning System (GPS) have been almost exclusively confined to geostationary earth orbits (GEO) or inclined GEO (IGEO). The objective of this research was to conduct trades of alternative orbits that potentially offer augmentation of the GPS for aviation navigation. The methodology consisted of examining orbits ranging from low earth orbit to GEO as well as elliptical orbits. These orbits were studied using accuracy as the primary measure of effectiveness as well as availability of host satellites, orbit slot locations, and user receiver performance as factors in the evaluation. A service volume model was used to express accuracy availability for the U.S. National Airspace System (NAS) as well as availability on a global basis. The study results show a clear performance improvement in the availability of system accuracy for equivalent numbers of medium earth orbit (MEO) satellites vs. GEO satellites. Because MEO orbits are non-geostationary they also offer global coverage and, as a result, provide the same performance advantage to any sovereign area of the world that establishes the associated ground support infrastructure.
Published in:	Proceedings of the 11th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1998) September 15 - 18, 1998 Nashville, TN
Pages:	1869 - 1876
Cite this article:	Galvin, Dennis M., "Advantage of Medium Earth Orbit for a GPS Augmentation System," Proceedings of the 11th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1998), Nashville, TN, September 1998, pp. 1869-1876.
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