Biased and Unbiased Estimates in GPS Processing

James L. Farrell

Abstract:	A recent publication [Ref. 1] called attention to the potential usage of biased estimation in applications involving navigation with GPS and other sensors. The presentation included results indicating a decided preference for biasing the navigation estimate away from the indicated solution. through suppression of the full weighting (gains) when poor GDOP was encountered. The prevailing initial reaction was interest, mixed with a general desire to diagnose either (1) those presented results or (2) the approach using unbiased estimates prevalent now. The paradox is resolved herein and. by citing additional references appearing in the same (PLANS 1988) conference. the results in Ref. 1 are reinterpreted in light of practices commonly employed in Kalman estimation for navigation data processing. Indirectly at least. Ref. 1 has caused attention to be drawn to the way interfaces are defined. and to the way algorithms are chosen. throughout the industry.
Published in:	Proceedings of the 45th Annual Meeting of The Institute of Navigation (1989) June 27 - 29, 1989 Alexandria, VA
Pages:	135 - 137
Cite this article:	Farrell, James L., "Biased and Unbiased Estimates in GPS Processing," Proceedings of the 45th Annual Meeting of The Institute of Navigation (1989), Alexandria, VA, June 1989, pp. 135-137.
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