Signal quality monitoring applied to spoofing detection

Recent improvements on receiver technologies, combined with the growth of new applications, increase the expectations for positioning and timing performance. New systems based on Global Navigation Satellite System (GNSS) are emerging, while safety and liability-critical applications relying on Global Positioning System (GPS) are becoming more popular than in the past. In this context, interfering signals are still a concern. While jamming blind the target receiver through the transmission of a high signal power, spoofing refers to a malicious transmission of counterfeit GNSS-like signals, that force the victim receiver to compute erroneous positions. Recently, new spoofing detectors have been proposed for civilian GPS receivers. Starting from signal quality monitoring techniques applied to multipath detection, this paper presents a low complexity strategy, based on the Neyman-Pearson theory, for the detection of intermediate spoofing attacks. In addition to conventional metrics to detect asymmetries on the correlation function, we use some extra-correlators, to reveal the presence of unexpected correlation peaks in the search space. The paper describes the designed algorithm with the appropriated theory, under some simplified hypothesis, addressing the problem associated to the thresholds setting in the decision process. The paper concludes the work presenting some open issues authors have to solve before practical implementation of the new technique.