S-Curve Shaping: A New Method for Optimum Discriminator Based Code Multipath Mitigation

Thomas Pany, Markus Irsigler and Bernd Eissfeller

Abstract:	The paper characterizes the optimum code multipath mitigation in a GNSS receiver which can be achieved by a linear combination of several correlators or equivalently by correlating the incoming signal with a code-tracking reference- function. After a review of currently used code multipath mitigation techniques, a new technique is developed to determine positions and weights of the correlators (or the shape of the code-tracking-reference-function) in order to achieve the best possible multipath mitigation performance within the chosen framework. It is based on the definition of an ‘optimum’ S-curve. A non-coherent code discriminator is formed by dividing the coherent discriminator by the punctual correlator. The technique is applied to BPSK(1) and BOC(1,1) signals for infinite, 16 MHz and 8 MHz bandwidth. Outside its linear region, the S-curve is slightly offset to avoid false stable tracking points as they occur for BOC signals. It is shown that within this approach high-bandwidth BPSK and BOC signals achieve virtually identically multipath envelopes. The resulting discriminator is implemented and tested in a software receiver.
Published in:	Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005) September 13 - 16, 2005 Long Beach Convention Center Long Beach, CA
Pages:	2139 - 2154
Cite this article:	Pany, Thomas, Irsigler, Markus, Eissfeller, Bernd, "S-Curve Shaping: A New Method for Optimum Discriminator Based Code Multipath Mitigation," Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005), Long Beach, CA, September 2005, pp. 2139-2154.
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