Improvement of GPS Relative Carrier Phase Positioning Accuracy by SNR Weighted Ambiguity Function Technique

Lawrence Lau, Esmond Mok

Abstract:	Interference and multipath are the main error sources of GPS measurement in land surveying. This paper describes an algorithm that mitigates specular multipath as well as interference in GPS differential carrier phase measure-ment by using signal-to-noise ratio. The focus is on mul-tipath as it accounts for the most of the total error budget in differential carrier phase measurement. Kernel of the processing algorithm is Signal-to-noise ratio Weighted Ambiguity function Technique (SWAT). The algorithm is demonstrated on static platforms in severe multipath environments. Test data sets are collected in the Hong Kong New Airport at Chek Lap Kok and roof of the Hong Kong Polytechnic University. Accuracy of SWAT is tested with pre-defined displace-ments on a X-Y-Z stage. Besides, the experimental results are compared to sidereal day-to-day repeatability. The data sets used for investigation are six epochs’ measure-ments. The results show more than 20% improvement in horizontal accuracy and 10% in vertical accuracy.
Published in:	Proceedings of the 55th Annual Meeting of The Institute of Navigation (1999) June 27 - 30, 1999 Royal Sonesta Hotel Cambridge, MA
Pages:	323 - 332
Cite this article:	Lau, Lawrence, Mok, Esmond, "Improvement of GPS Relative Carrier Phase Positioning Accuracy by SNR Weighted Ambiguity Function Technique," Proceedings of the 55th Annual Meeting of The Institute of Navigation (1999), Cambridge, MA, June 1999, pp. 323-332.
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