Velocity Consistency Checking Based GNSS Spoofing Detection Method for Vehicles.

Autonomous driving, Unmanned Aerial Vehicles (UAVs), and various other vehicular navigation schemes heavily depend on the accurate Position, Velocity, and Timing (PVT) information offered by Global Navigation Satellite Systems (GNSSs). Meanwhile, the security of this vital service is challenged by spoofing attacks, which aim to deceive users by inducing false PVT solutions. Therefore, a timely alarm to victim users in the context of spoofing is crucial to the security of vehicular navigation. As the counterfeit signals are transmitted from a spoofer rather than real satellites, the spatial information is hard to be coordinated. To this end, the Doppler shift, which essentially reveals the spatial features of the transmitter and receiver, is regarded as an effective metric for spoofing detection. Especially for a vehicle, induced by its relative motion with respect to the spoofer, Doppler bias is appended to the raw measurement, providing an observable signature of spoofing. Conventional approaches tend to directly monitor the Doppler bias concealed in the measurement, by committing to eliminate the remaining part caused by satellite motion and clock drift. However, the resulting requirements (such as keeping static for initialization, random motion patterns, and multi receivers) introduce considerable complexity that limits their practical applicability. Moreover, the commonly utilized single-antenna assumption renders them ineffective against multi-antenna spoofing attacks. In this paper, we propose a new approach that indirectly exploits the Doppler bias by examining the affected consistency of velocities. We introduce a Direct Velocity Determination (DVD) method, which calculates the velocity directly from the Doppler measurements. The provided solution is then utilized for consistency-checking along with the velocity given by the conventional pseudorange-aided approach. We thoroughly investigate the adverse impact of Doppler bias on these velocities and analyze their consistency performance across different scenarios. Also involved are the Generalized Likelihood Ratio Test (GLRT) based spoofing detector and its performance evaluation. Field tests are conducted to validate the effectiveness of the proposed GNSS spoofing detection method. The superiority of the proposed method is demonstrated in comparison with the previous Doppler-based methods as well as the widely used Receiver Autonomous Integrity Monitoring (RAIM) method.