Research on Integrity Monitoring Performance Test Method of GNSS-Based Train Positioning Units

With the rapid increasing applications of Global Navigation Satellite System (GNSS) technology in railway train control systems, the specific performance test and evaluation methods and platforms for train positioning units have received more attention in recent years. Considering the varieties and uncertainties in the environmental conditions and critical requirement of safety for railway trains, commercial grade GNSS receivers may not meet specified requirements in safety-related railway operations. In this paper, composition of the GNSS-based train positioning units is presented, where an overlay module for autonomous integrity monitoring is integrated. It enables the implementation of GNSS-based train positioning units under different conditions, even with faults or failures in the raw measurements. Performance properties and the test process of the positioning units are introduced, and the integrity monitoring performance test method dedicated to the train positioning application is designed. Based on results from different testing objects, the feasibility of the frame for test and effectiveness of the presented performance evaluation method are demonstrated, which show the potentials in safety-related GNSS railway applications in the future.