Criteria for GNSS Multipath Performance Assessment

Markus Irsigler, Jose Angel Avila-Rodriguez and Guenter W. Hein

Abstract:	A common approach to describe the effects of specular multipath is the computation of multipath error envelopes. These graphs illustrate the resulting ranging error as a function of geometric path delay under idealized conditions (dedicated multipath relative amplitude, consideration of only one multipath signal, no shadowing effects). Despite the simplifications assumed in this model, the multipath error envelopes remain an indispensable tool that is very well suited to compare the multipath performance of different signals, because the appearance of the resulting error envelopes directly reflects differences in modulation schemes or chipping rates. Apart from the computation of multipath error envelopes, there are also other, more complex models that consider more than one multipath signal in different multipath environments. The most complex ones are statistical channel models. The paper starts with a brief description of such a statistical model. Based on model parameters for different environments, the resulting multipath errors are computed for the current GPS C/A code as well as for two Galileo L1 signal candidates. It is assumed that the multipath errors obtained with this model are typical for the underlying environment and can serve as a reference for the subsequent analyses. Thereafter, much simpler multipath models as well as the computation of multipath errors based on multipath error envelopes are discussed in detail. The main objective is to determine, whether or not a particular approach of computing multipath errors leads to errors comparable to those obtained by more complex statistical models and whether or not the complex models can be replaced by simplified ones. The main motivation of this paper is to provide methods for assessing the multipath performance of a dedicated signal/receiver/environment combination and to provide the necessary means for the computation of realistic multipath errors that can be used as an input for GNSS error budget computations.
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:	2166 - 2177
Cite this article:	Irsigler, Markus, Avila-Rodriguez, Jose Angel, Hein, Guenter W., "Criteria for GNSS Multipath Performance Assessment," 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. 2166-2177.
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