Fast Narrowlane Ambiguity Resolution: Method and Results

Zuofa Li, Yang Gao and John B. Schleppe

Abstract:	The use of dual-frequency GPS data can improve the accuracy and reliability of carrier phase based positioning. The improvement in accuracy is achieved by using the narrowlane carrier phase observable, a combination of dual-frequency GPS data with a wavelength of about 10cm. The success of using narrowlane carrier phase, however, lies in the correct resolution of the integer narrowlane ambiguities. This paper presents the implementation and the results of a method of fast narrowlane ambiguity resolution developed at Position Inc. The method consists of four consecutive steps. First, widelane ambiguities are resolved using the optimized ambiguity resolution method. Secondly, the initial narrowlane ambiguities and their error variances are estimated using the ionosphere carrier phase combination and the resolved widelane ambiguities. Thirdly, a narrowlane ambiguity search procedure is performed based on a least-squares adjustment. Finally, the narrowlane ambiguities are validated. As the change of 17 cycles in the ionosphere carrier phase combination results in a shift of two cycles in the narrowlane carrier phase, only a few potential narrowlane ambiguity combinations exist using the described search procedure. This can dramatically reduce the ambiguity resolution time. The proposed method has been implemented into Jupiter, a commercial GPS data post-processing software package of Position Inc., and tested with various data sets. The numerical results indicate that the narrowlane ambiguities can be resolved almost instantaneously and reliably once the widelane ambiguities are successfully resolved.
Published in:	Proceedings of the 10th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1997) September 16 - 19, 1997 Kansas City, MO
Pages:	1767 - 1772
Cite this article:	Li, Zuofa, Gao, Yang, Schleppe, John B., "Fast Narrowlane Ambiguity Resolution: Method and Results," Proceedings of the 10th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1997), Kansas City, MO, September 1997, pp. 1767-1772.
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