Quality Control Issues Relating to Instantaneous Ambiguity Resolution for Real-Time GPS Kinematic Positioning

Shaowei Han

Abstract:	For real-time, centimeter accuracy GPS kinematic positioning applications, it would be extremely useful if the estimation of the integer ambiguities could be carried out instantaneously (on a single epoch basis). The problem can be partitioned into two: (a) development of a fast ambiguity search technique, and; (b) addressing the quality control issues. In this paper, an integrated method for the instantaneous ambiguity resolution using dual-frequency precise pseudo-range and carrier phase observations has been used. The algorithm combines the search procedures in the coordinate domain, the observation domain and the estimated ambiguity domain (and therefore benefits from the integration of their most positive elements). A three-step procedure is then proposed to enhance the reliability of the ambiguity resolution by: (1) intproving the stochastic model for the double- differenced functional model in real-time; (2) refining the criteria which distinguish the integer ambiguity set that generates the minimum quadratic form of residuals from that corresponding to the second minimum one, and; (3) developing a fault detection and adaptation procedure. Three test scenarios were considered, one static baseline (11.3km) and two kinematic experiments (baseline lengths from 5.2km to 13.7km). These have shown that the mean computation time for one epoch is less than 0.1 second, and that the success rate reaches 98.4% (compared to just 68.4% using standard ratio tests). The data were processed post-mission, but in a simulated real-time processing mode.
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:	1419 - 1430
Cite this article:	Han, Shaowei, "Quality Control Issues Relating to Instantaneous Ambiguity Resolution for Real-Time GPS Kinematic Positioning," Proceedings of the 9th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1996), Kansas City, MO, September 1996, pp. 1419-1430.
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