Spoofing Monitoring of GNSS Localization: A LDSASM Architecture for GNSS/Odometer-based Train Positioning

Abstract-The next generation railway train control system is designed with the utilization of the GNSS (Global Navigation Satellite System) localization to enhance the autonomy of the onboard equipment and effectively reduce the maintenance cost. In order to guarantee the safety and effectiveness of GNSS-based localization under complex GNSS observing conditions with potential GNSS spoofing attacks, the monitoring of GNSS spoofing is of great significance in an enhanced train localization system. In this paper, a spoofing monitoring solution is proposed within the GNSS positioning domain and measurement domain with assistance of the train odometry system, over conventional spoofing countermeasures through the specific signal processing operations. A GNSS/odometer integrated localization solution is employed, which only uses wheel pulse counting measurements from the odometer without relying on extra sensors. By utilizing both the odometer and trackmap data, a hierarchical LDSASM (Location Determination System Autonomous Spoofing Monitoring) architecture, covering both the odometer-channel initial detection stage and channel-wise spoofing detection stage, is established to identity the existence of the spoofing attack. Results from the GNSS spoofing injection tests demonstrate the effectiveness of the proposed solution under different satellite observing conditions. It is illustrated that the solution is simple for implementation and of great significance in the trustworthy train localization for novel GNSS-enabled railway systems.