Multipath Mitigation, Benefits from using the Signal-to-Noise Ratio

Jean-Marie Sleewaegen

Abstract:	In the recent years, there has been a growing interest in the use of the signal-to-noise ratio (SNR), output by a GPS receiver, in the field of multipath mitigation. This paper aims at giving a theoretical insight into the SNR in presence of multipath, in order to assess its real capabilities with this respect. In a first part, the code and carrier tracking processes of a generic GPS receiver are analyzed in the presence of multipath. The resulting SNR error is computed together with the phase and code errors. Three important characteristics of the SNR error are deduced : its envelope, its mean and its standard deviation. A comparison is made with the corresponding characteristics of the phase and code errors. Useful links are inferred that constitute the foundation of the SNR based multipath mitigation schemes. The large influence of the correlator spacing is discussed. The second part presents an original code multipath mitigation technique for a permanent GPS receiver. It is shown how the traditional “day-to-day repeatability” method can be dramatically improved by use of the SNR. This SNR aiding technique is demonstrated on data from a permanent IGS receiver. The code multipath standard deviation was reduced by 65%, which is 28% better than what was achieved by the “day-to-day repeatability” alone.
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:	531 - 540
Cite this article:	Sleewaegen, Jean-Marie, "Multipath Mitigation, Benefits from using the Signal-to-Noise Ratio," 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. 531-540.
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