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Simulated-based GNSS for Maglev Train Localization Performance Analysis

GNSS (Global Navigation Satellite Systems) have great potential for determination of Maglev train location during dynamic movement in very high speed. The localization performance of GNSS for high speed Maglev train should be analyzed to test the feasibility of this technology. However, there are no Maglev lines operating at 600km/h or higher, the adoption of GNSS for Maglev train should be analyzed in advance, thus the simulation-based approach is the only option. This paper focuses on the simulation procedure and the analysis method for the localization performance of GNSS in the scenarios combined high speed locomotive scene and the simulated 3D environment. The results will provide evidence for the adoption of GNSS in high speed Maglev trains. The fundamental concept for the simulation procedure is that the train trajectory generation method takes the line constrain and train kinetic parameters constrain into account. The trajectory describes the train operating conditions during the whole journey. The speed limit, curve types are the constrains related to the line, the train braking force, traction force, air resistance and so on are the constrains associated with the train kinetic parameters. Both kinds of constrains are required as the input of the trajectory generation algorithm. Using these inputs, a file containing relative 3D location, 3 axis acceleration, 3 axis angular rate at each moment can be generated, which builds the relationship between a prechosen (designed) line and the train kinetic parameters. The generated trajectory can be used as the profile for further scenario-based train localization. Based on the generated trajectory, the GNSS localization process is simulated through the GNSS signal simulator, which delivers GPS L1/L2 and BDS B1/B2 signals. The generated signals not only include the pure GNSS signal, but also contain the signal propagation under given environmental scenarios (multipath and signal blockage). The 3D environmental scenarios refer to condition during the train running, such as a certain train en-route conditions can include open sky, dense urban city and train stations. The localization performance can be analyzed through a complete simulation procedure. The simulation process is divided into four parts, including model building, model digitalization, simulation of GNSS signal propagation effect, the replay of the scenarios using 3D model and the trajectory. Finally, with the whole procedure, the GNSS receiver will receive the GNSS signals after the simulation as the replay procedure goes. The amount of simulation data can be acquired depending on the amount of simulations, which leads the quality of the generated trajectory as comparable with the reality train movements on the line.