Ambiguity Resolution and Success Rates with an Integrated GNSS - Pseudolite Positioning System

Sandra Verhagen

Abstract:	The requirements on the precision of real-time kinematic positioning have become higher and higher in recent years. The Global Positioning System (GPS) enables us to meet these requirements in many situations. However, there are still situations where GPS, or any Global Navigation Satellite System (GNSS), will not provide users with the desired precision. These situations occur for example in environments with obstructions or at times and places where the satellite constellation does not provide a good geometry. The precision can be improved in some of these situations by the integration of GNSS with pseudolites. The goal of this study was to give a quantification of the improvement that can be expected. One way to achieve this is to compute the success rate of integer ambiguity resolution. A high success rate indicates a high probability of fixing the integer ambiguities to the correct values and thus enables estimation of the baseline coordinates with higher precision. It was shown that it is indeed possible to obtain very high success rates with an integrated GNSS - pseudolite positioning system. At times where GNSS by itself can only achieve success rates of 75%, an integrated system can achieve success rates of 99%. I have considered various measurement scenarios, varying the number of pseudolites, location(s) and observation types. Even though the improvement was considerable in all cases, it was shown that the choice of these parameters is important. It is possible to base this choice (partially) on the success rates, which can be computed without the need of actual observations.
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:	3036 - 3043
Cite this article:	Verhagen, Sandra, "Ambiguity Resolution and Success Rates with an Integrated GNSS - Pseudolite Positioning System," 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. 3036-3043.
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