A Dual Antenna GNSS Spoofing Detector Based on the Dispersion of Double Difference Measurements

Abstract

This paper presents the development of a dual-antenna GNSS spoofing detection technique based on the analysis of the dispersion of the double differences of carrier phase measurements produced by two GNSS receivers. No synchronization of the receivers is needed for the algorithm to properly work. The algorithm is derived from the idea of the Sum of Squares (SoS) detector, recently presented as a simple and efficient way to detect a common angle of arrival for all the GNSS signals arriving to a pair of antennas. The presence of such a common angle is recognized as an undiscussed indication of non-authentic GNSS signals. Nonetheless, some limitations can be identified in the SoS algorithm. First of all, the assumption that all the signals arrive from the same source; situations are possible in which the receiver tracks only a subset of counterfeit signals, out of the whole signal ensemble. The idea presented in this paper intends to overcome such limitations, properly modifying the SoS detection metric to identify subsets of counterfeit signals. The analysis is supported by several simulation tests, in both nominal and spoofed signal conditions, to prove the effectiveness of the proposed method.