| As the train speed continues to increase,the requirements for safety are getting higher and higher.Among them,the accuracy for safety and reliability of train positioning is the key to ensure the high speed operation of the train.Considering the real-time,high-precision and external environment interference requirements of train positioning,this paper proposes to use the map matching technology based on speedometer/INS integrated navigation system to accurately locate the train and verify the method by experiment The main research include the following aspects:1.Calibration method of speedometer under large angle conditions.The error factors of the speedometer are analyzed,and the output of the speedometer under the large angle condition is given.Based on the traditional condition calibration method,the installation error angle and the scale factor error under large angle conditions are derived.In order to further improve the calibration accuracy,it is proposed to reduce the calibration error by applying multiple calibration methods which using iterative to improve accuracy.Finally,using the simulation data and the actual measured data of the sports car verify the speedometer calibration method and the calibration method.2.A map matching algorithm based on speedometer/INS integrated navigation system is designed.The basic principle of map matching algorithm is introduced,and the basic algorithm of map matching based on speedometer/INS integrated navigation system is briefly explained.According to the driving state of the vehicle and the characteristics of the map matching algorithm,the map matching algorithm based on the speedometer/INS integrated navigation system is divided into four stages: the road search stage,the normal driving stage,the road conversion stage and the abnormal processing stage.Design at each stage according to different situations.Finally,the map matching algorithm is verified by using the generated data simulation,real data simulation and sports car measured data.3.In the normal driving stage,an improved translation vector correction method is studied.Based on the map matching algorithm of translation vector,according to the characteristics of the output point information of the speedometer/INS integrated navigation system,this method proposes to compensate the translation amount by the correction amount,reduce the longitudinal position error divergence,and use the modified correct vector to correct the integrated navigation point,then the compensated positioning point is substituted into the map matching algorithm for optimal estimation.Finally,the improved translation vector correction method is verified by using simulation data and sports car measured data.4.In the road conversion stage,an improved road conversion algorithm was studied.On the basis of the weighting method,the algorithm comprehensively considers the positional relationship between the positioning point with the original road segment and the road segment.The road of the current vehicle are selected according to different situations. |
