| Accurately obtaining the real time train position information is especially important for the train control system.That is to say,accurate and continuous train positioning result directly affects the driving safety of the train.The traditional method for train positioning is based on the track circuit or the sensor method.In recent years,some new train positioning methods have been proposed,such as the Beidou satellite navigation system and long-term evolution.These new technologies have gradually become new tools for studying train positioning.Under such background,the thesis proposes a method of dividing the road section through the electronic map threshold to realize the continuous and autonomous positioning of the running train.Furthermore,the method improves the safety of the train.The thesis includes the following parts.(1)Firstly,the thesis describes the principle of the existing train positioning method in details,then proposes the principle of the train positioning method we use in this thesis.Since most trains pass through tunnels,turnouts,platforms,and other scenes during the driving process,we divide the running process of the train into good and weak signals road sections or even no signals road sections according to the ability of the train to receive signals by using the known orbital electronic maps.When the signals are will,Beidou satellite navigation system and the next-generation train communication system are used to determine the position of the train.In this case,the positioning method on the one hand uses the next-generation train communication system to assist the Beidou satellite navigation to quickly obtain the initial position.On the other hand,it can retain the advantages of high positioning accuracy and can deal with the failure of the train navigation receiver at the same time.Using the next-generation train communication system to locate,this is an idea scheme designed by using redundancy.When the signals are weak or there is even no signal,we use the way combined with the advantages of Beidou satellite navigation and inertial navigation.The advantage of inertial navigation in high accuracy in a short time can compensate for the failure of Beidou satellite navigation.At the same time,when the signal is better,Beidou satellite navigation can correct the accumulated error of inertial navigation system.The positioning results in these two cases are converted into one-dimensional orbital positioning data by the orbital map projection method,which is to improve the positioning accuracy for a closer step.(2)In the view of the above positioning method,a hardware train position data acquisition circuit is made,and the simulation scenes are set to be tested,the test results are uploaded to the host computer,and then the data collected by the host computer is processed and analyzed in MATALABR 2014 a.Finally we get the accuracy and speed error of the trainpositioning.The positioning method based on the next-generation train communication system needs the assistance of the base station,but the base station information cannot be obtained during the test,we deal this part as a theoretical analysis in the simulation environment.(3)From the above theoretical analysis results,it is found that the above positioning method has an error due to a lack of positioning accuracy for a train traveling under a station or rampage scenario.Therefore,an orbital electronic map is used in this case.We divide these scenarios out of the train travel route,and then use the image analysis method based on the video acquisition of train passing through route to achieve the positioning of the train.This positioning method combine the orbit electronic map with the Beidou satellite can determine the position of the train and improve the positioning accuracy.This method is also an innovation point in the thesis.The proposed positioning target can be completed by experimentally verifying the method of determining the train position studied in this thesis. |
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