Research On Performance Testing And Evaluation Method Of GNSS-Based Train Positioning Units

Train Positioning Unit(TPU)is an important part of the train control system of satellite-positioning-technology-based.With the rapid increasing applications of Global Navigation Satellite System(GNSS)technology in railway applications,requirements for railway applications respresented by the train control system of GNSS-based are are increasingly demanding.The introductuin of GNSS-based positioning technology in TPU can effectively reduce the dependence on ground equipmentand and maintenance costs.However,the development and application of TPU need to solve the varities and uncertainties in railway environmental conditions.It is necessary to carry out research on test and evaluation methods in the GNSS-based railway field,provide support for the rational application of satellite positioning technology,and provide the basis in evaluating and testing of safety and related performance for railway signal system.The railway-specific property system is established by comparing the correspondence between railway signal system and important performance properties of GNSS in this paper.Test and evaluation methods are proposed for each property characteristic to form an effective performance test and evaluation system.The main research work in this thesis includes:(1)The general structure of the TPU including the Positiong Calculation Module,the Security Inspection Module and the Positioning Decision Module is given.The correspondence between GNSS and train control system properties are analyzed.The railway-specific property system is summarized.(2)Combined with the field and simulation test conditions,the railway special test scenario is designed based on the demand of property system and test.Test methods for basic positioning performance properties and supplementary performance properties are proposed.(3)Combined with the test methods and results,the specific evaluation methods of the positioning performance(accuracy,integrity monitoring,availability,etc.)and supplementary performance(Time to First Fix,Reacquisition Time,Pseudorange accuracy,etc.)of the TPU are analyzed.Finally,an improved Analytic Hierarchy Process is introduced to establish the overall performance evaluation system.In this paper,in order to validate the performance of proposed test and evaluation method,an experimental test scenario is designed by using the existing simulation test platform and railway field data.The test evaluation and calculation of each property are given.The feasibility of the presented performance property system,test and evaluation method are demonstrated,which meet the demands of railway application scenarios,provide a basis for the performance requirements of railway positioning equipment and early reserves for the establishment of GNSS-based railway positiong system.The thesis includes:figure 82,table 39,and reference 70.