Reliability Analysis of the Integrated Navigation System based on Real Trajectory and Calculation of Safety Margin between Trains

A safety margin must always be maintained between trains. To this end, position data of all trains must be provided to the railway system in real time. Basically, this data has been provided based on the infrastructure installed on the railway. However, enormous costs are required to install the infrastructure, and continuous maintenance is required. In addition, cases of accidents due to un-detection or false-detection of trains are being reported as news. Due to these problems, researches on infra-less navigation system for trains have been conducted. Taking into account the blocking phenomenon of Global Positioning System (GPS)/Global Navigation Satellite System (GNSS) signals in tunnels, the navigation system for trains should constitute an integrated navigation system. However, the accuracy and reliability of navigation solution provided by the integrated navigation system are not always satisfied. And this can lead to instability of the railway system. Therefore, the navigation solution for trains must have high accuracy and also the reliability information of the corresponding navigation solution must be provided. In this paper, we construct an Inertial Navigation System (INS)/GPS/Non-Holonomic Constraints (NHC) integrated navigation system for trains with NHC motion. A simulation trajectory is generated considering the real trajectory, and the accuracy and reliability of the navigation information according to the trajectory and measurements are analyzed together. And based on this information, we propose a method to calculate the safety margin between trains. The performance of the proposed technology is verified through a real trajectory-based Monte Carlo simulation.