Analysis of Multiple GPS Antennas for Multipath Mitigation in Vehicular Navigation

R. A. Nayak, M. E. Cannon, C. Wilson and G. Zhang

Abstract:	The most important issue when using GPS for urban vehicular navigation is the position reliability which usually depends on the nature of the environment. In particular, the presence of urban canyons and foliage can cause significant degradation in satellite visibility as well as high multipath. Although GPS information tends to be integrated with other dead-reckoning sensors to increase position availability, it is often difficult to isolate satellites with significant multipath effects, which can then corrupt the integrated position solution. The objective of this paper is to assess the feasibility of using multiple antennas to isolate and detect multipath on pseudoranges so they can be rejected before they contaminate estimated vehicle positions. One of the properties of multipath is that it decorrelates rapidly as a function of distance, so antennas spaced at least 0.5 m apart may be subjected to different multipath conditions such that detection may be possible. Land tests were conducted with four antenna/receivers in Calgary under various environments including open sky, urban canyon and dense foliage conditions. The correlation of multipath between the antennas is analyzed for each of these environments, as is the overall satellite availability and multipath as a function of the environment. A multipath mitigation technique based on statistical reliability testing is presented.
Published in:	Proceedings of the 2000 National Technical Meeting of The Institute of Navigation January 26 - 28, 2000 Pacific Hotel Disneyland Anaheim, CA
Pages:	284 - 293
Cite this article:	Nayak, R. A., Cannon, M. E., Wilson, C., Zhang, G., "Analysis of Multiple GPS Antennas for Multipath Mitigation in Vehicular Navigation," Proceedings of the 2000 National Technical Meeting of The Institute of Navigation, Anaheim, CA, January 2000, pp. 284-293.
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