A Combined Filter for GPS-Based Attitude and Baseline Estimation

Lisa M. Ward and Penina Axelrad

Abstract:	This paper describes a methodology for combining at- titude and baseline estimation into one comprehen- sive filter. The nominal filter states include attitude quaternion errors, angular velocity errors, and baseline errors. The approach in terms of baseline errors is to estimate a scalar correction to one baseline, an angle correction to the second baseline, and a vector correc- tion to the third. Reducing the baseline error states in this way provides the necessary attitude observability while allowing for baseline calibration. Previous approaches have relied on determining ac- curate baselines first (either on-orbit or on the ground) and then using those baselines for attitude estimation. The method presented here combines these two steps into one algorithm. The advantage is that baseline cal- ibration can be performed while simultaneously pro- ducing attitude information. Results from simulated data as well as flight data from the RADCAL and CRISTA-SPAS satellites are presented.
Published in:	Proceedings of the 9th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1996) September 17 - 20, 1996 Kansas City, MO
Pages:	1047 - 1061
Cite this article:	Updated citation: Published in NAVIGATION: Journal of the Institute of Navigation
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