Fast Ambiguity Resolution for GPS/IMU Attitude Determination

Yunchun Yang and Jay A. Farrell

Abstract:	This article describes a fast (even instantaneous) ambiguity resolution algorithm for GPS/IMU attitude determination with a short baseline by combining pitch and roll estimates calculated based on outputs from a low cost Inertial Measure Unit (IMU), the fixed short baseline length, and the GPS satellite geometry. It is shown that the size of the integer ambiguity search space is greatly reduced. The known baseline length, and the known pitch and roll angles restrict the valid integer ambiguity candidates to those resulting in solution of baseline on a circle with a radius equal to or less than the fixed baseline length. This article will derive and analyze the suggested approach. Issues related to this algorithm are discussed and analyzed. Though the algorithm is developed for a single baseline two-antenna GPS/INS attitude determination system, it can be extended to multiple baselines with better performance. The algorithm extends without modification to applications where a tilt-meter is used instead of an IMU. Also, this algorithm can be extended without an IMU to land vehicle or sea-craft attitude determination applications that the roll and pitch angles are small. Keywords: Global Position System, Inertial Measure- ment Unit, Attitude Determination, Carrier Phase, Inte- ger Ambiguity Resolution
Published in:	Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001) September 11 - 14, 2001 Salt Palace Convention Center Salt Lake City, UT
Pages:	2990 - 2997
Cite this article:	Yang, Yunchun, Farrell, Jay A., "Fast Ambiguity Resolution for GPS/IMU Attitude Determination," Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001), Salt Lake City, UT, September 2001, pp. 2990-2997.
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