Experimental Results for GPS Multipath Mitigation Using Multiple Reference Antennas

Curtis A. Shively

Abstract:	A method has been previously proposed for minimizing the impact of multipath on accuracy of the GPS Local Area Augmentation System (LAAS) by averaging measurements from multiple ground reference antennas. This paper presents the results of an experimental evaluation of this averaging method for a user whose antenna is also located on the ground (building roof) in the same multipath environment as two reference stations. The improvement is characterized by reduction in variance of position based on using the average of differential corrections from the two references, in comparison to using the reference corrections separately. The reduction achieved is typically what would theoretically be expected for a user who is experiencing the same degree of multipath corruption as the two references. Moreover, the reduction typically improved for a second experiment in which the separation between the reference antennas was increased. However, the fact that multipath appears to be significantly correlated among the antennas in this rooftop environment suggests that more insight can be gained by repeating the experiment in a better environment with larger antenna separations.
Published in:	Proceedings of the 1997 National Technical Meeting of The Institute of Navigation January 14 - 16, 1997 Loews Santa Monica Hotel Santa Monica, CA
Pages:	243 - 252
Cite this article:	Shively, Curtis A., "Experimental Results for GPS Multipath Mitigation Using Multiple Reference Antennas," Proceedings of the 1997 National Technical Meeting of The Institute of Navigation, Santa Monica, CA, January 1997, pp. 243-252.
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