Doppler-Based RAIM for GNSS Spoofing Detection in Vehicular Applications

Modern vehicular applications heavily rely on accurate Position, Velocity, and Timing (PVT) information provided by the Global Navigation Satellite System (GNSS). However, the vulnerability of GNSS to spoofing attacks presents a significant threat to vehicle safety and efficiency. Rapid detection of spoofing attacks is thus vital for ensuring the security of vehicular navigation. Among existing methods, Doppler shift emerges as a typical means of spoofing detection in vehicular applications, as the anomalous Doppler bias associated with the user's real state serves as a distinctive indicator of spoofing. Conventional approaches, however, focus on directly observing Doppler bias, which remains embedded within raw measurements and necessitates additional complexities, thereby limiting their effectiveness. In this paper, we introduce Doppler-based Receiver Autonomous Integrity Monitoring (D-RAIM) as a practical method for GNSS spoofing detection in vehicular applications. In contrast to direct monitoring methods, D-RAIM indirectly detects spoofing by assessing the impact of Doppler bias on Doppler positioning integrity. Operating without the need for external sensors, D-RAIM performs integrity monitoring by leveraging residuals derived from Doppler positioning equations, offering a flexible approach for standalone GNSS receivers. Through simulation experiments and field tests, we validate the effectiveness of D-RAIM, demonstrating its broader applicability and robustness compared to previous methods. Overall, the proposed D-RAIM method offers a practical solution for GNSS spoofing detection in vehicular applications, characterized by its flexibility, robustness, and wider applicability in enhancing vehicular navigation security.