Detection of Spoofing Threats by Means of Signal Parameters Estimation

The increasing use of satellite navigation systems in ordinary life application, is demanding more and more protection of the position information, in order to provide not only accurate solutions, but also reliable and "trustable" information. For this reason, new algorithms, strategies techniques are being investigated and designed, in order to provide added value features to satellite navigation receivers. In particular it is gaining relevance the possible spoofing that may threat the receivers; if in the past this has been a specific problem restricted to military or sensitive applications, with the wide use of GNSS in critical networked infrastructures and commercial services (e.g., road tolling, vehicle insurance schemes), the malicious interest in cheating the receiver or in disrupting the nominal operations isexpected to increase. It is well known that spoofing is more sinister than intentional interference because the target receiver might not detect the attack and consequently generate erroneous data. Within the described scenario, the importance for the GNSS community of investigating spoofing and anti-spoofing techniques is essential. In this paper we investigate the possible use of multipath estimation techniques as spoofing detector, relying on the likelihood of the estimated parameters with respect to a multipath affected scenario. In particular we focus on the Coupled Amplitude Delay Locked Loops (CADLL) structure that was proposed in [5][6] for multipath robust receivers. The CADLL was originally designed as a pure multipath estimation and mitigation architecture. However, its ability to accurately estimate the multipath rays features (and their evolution in time) allows to use it to detect spoofing signals coming into view.