Simulation-based GNSS Train Localization Performance Evaluation Software Design & Implementation

With the rapid growth of railway transportation demand,the train control system is developing towards intelligence and self-conscious.To improve the efficiency of train operation and reduce trackside equipment,GNSS(Global Navigation Satellite System)-based train localization unit is the key to realize trainborne self-conscious localization.In railway domain,there is a high requirement for safety.The GNSS-based train localization unit is required to be tested through field or simulation tests,the goal is to evaluate its applicability and availability performance.For the field test of the localization unit,there are several problems such as the difficulty in reproducing extreme scenarios,poor controllability of GNSS signal field test and high costs.Therefore,perform simulation tests in the laboratory,study and develop Simulation-based GNSS Train Localization Performance Evaluation(Si GTE)software,carry out the evaluation process for the train localization unit,the procedure based on Si GTE will promote satellite-based train localization techniques in railway.The main content of this thesis includes:(1)Studied the train simulation and GNSS signal propagation parametric value generation method towards 3D train trajectory.Based on the track condition and train kinetic parameters,the 3D location coordinate projection and trajectory generation method using train operation condition conversion and digital track map method is proposed.Using Canny edge extraction algorithm,the environmental scenario elevation blockage angle is calculated,thus the GNSS signal power and visibility parameters are presented.(2)Studied GNSS-based train localization accuracy evaluation method.According to GB/T 6379 Accuracy(Trueness and Precision)standard definition for accuracy evaluation,the GNSS-based train localization results are evaluated and analyzed with 4 accuracy evaluation methods: easting and northing error,Circular Error Probable(CEP),error ellipse and Mahalanobis distance.(3)Designed and developed the Si GTE software.Si GTE software is consists by 3 modules: simulation scenario parameter generation module,information interaction module and GNSS localization accuracy evaluation module.The simulation scenario parameter generation module can generate train trajectory,continuously adjustable GNSS signal power and visibility parameters.The information interaction module receives the train trajectory and GNSS signal control parameters,send commands to GNSS signal simulator,thus generating GNSS RF signal.The GNSS localization accuracy evaluation module receives the output data of the train localization unit,evaluate analyze the location using 4 accuracy evaluation methods.The thesis verifies the simulation function and performance of the Si GTE software using the field collected Shenyangxi Station to Heishanbei Station(78 km)high speed railway line data and Yuzhufeng Station to Nachitai Station(130 km)secondary line data.Si GTE software generates the parameters of the train trajectory and GNSS signal propagation of the 2 scenarios,control GNSS signal simulator,and evaluate the accuracy of the train localization unit output.The evaluation results show that,in open sky environment,the average value of easting error is 0.10 m,northing error is 0.17 m,CEP50 is 0.85 m,the major axis of 1? error ellipse is 0.79 m,and the average Mahalanobis distance is 0.99 m,which has high localization accuracy and proves that Si GTE meets the simulation requirements.