Research On Train Positioning System Based On GPS_DR

In recent years, high speed railway has been developed quickly in our country, with the continuous speed-raising of trains. This is why higher level of safety is demanded on high-speed railway, and accordingly we need to ensure that all the information of the running trains could be transferred correctly in time. Train positioning system is a crucial part of train control system, by which the positioning information can be acquired accurately and rapidly to secure the safety and effectiveness of trains.With the development of science technology, the train positioning techniques have been improved constantly and the conventional positioning technologies cannot meet the needs of positioning trains. The classical train positioning system gets the positioning information and other information mainly by using the equipment near the track. However, this kind of positioning system doesn’t support the dynamic traffic assignment of the lines, which leads to a large amount of work and high cost for maintenance. As a result, a new positioning method is in demand.The background and global development of train positioning technology was studied and analyzed in this paper; furthermore, the train positioning system based on GPS and DR was designed according to the practical needs. The composition, the functions and the relative theories of the system were studied and learned deeply. The GPS OEM board, the DS1307clock chip, the data storage chip, the angular gyroscope, the connection circuit of wireless transfer module and FPGA, as well as the conditioning circuit for output signal of wheel impulse sensor were designed; The program to acquire, process, save and transfer data was written by using hardware description language HDL.The train positioning interface at the host computer was developed on the platform of VB. The communication between the upper machine positioning display and the lower machine data collector was realized by using MSComm controls and wireless transmission; the basic functions of map operation, the real-time display of train position and the historical trajectory replay were achieved by embedding MapX map development controls; the positioning data was saved by employing Access database technique to facilitate future uses and researches; the speed-monitoring function was designed by using Locomp component developing tools. It is proved by field testing that this system works well in the positioning and monitoring of trains.