Spatial Spoofing Signal Suppression Using the Constellation Covariance Matrix

L. Kurz, S. Zorn, T.G. Noll

Abstract:	This paper focuses on the detection and mitigation of spoofing signals generated by GNSS repeaters. Applied methods are based on array antenna processing techniques. Algorithms for suppressing RFI- and spoofing-signals in the spatial domain are revisited. A receiver architecture for mitigating both kinds of interference is presented. The proposed architecture is based on a two-stage filtering scheme separated by the correlation process. Repeater signal suppression is based on the so-called constellation covariance matrix which is composed of multiple correlator output signals. However, filter performance suffers from cross-correlation between the array responses to the satellite signals in LoS of the receiver. A method for enhancing the constellation covariance matrix by pre-filtering the correlator output signals is introduced. Simulations show that the enhanced constellation covariance matrix enables almost perfect suppression of repeater signals. Field tests with a realtime implementation of the proposed architecture and a custom build repeater have been carried out as well. A worst-case scenario shows that the proposed architecture is capable to reduce the absolute position error from 55 m down to 22 m by using the constellation covariance matrix w/o applying pre-filtering. The approach based on the enhanced constellation covariance matrix has not been verified yet but will likely be tested in a future field test.
Published in:	Proceedings of the 29th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2016) September 12 - 16, 2016 Oregon Convention Center Portland, Oregon
Pages:	3044 - 3052
Cite this article:	Kurz, L., Zorn, S., Noll, T.G., "Spatial Spoofing Signal Suppression Using the Constellation Covariance Matrix," Proceedings of the 29th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2016), Portland, Oregon, September 2016, pp. 3044-3052. https://doi.org/10.33012/2016.14783
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