Position Detection System Using GPS for Tilting Train

摘要

We have developed a new train position detection system using GPS, and curvature collation of track. This system has the following advantages against the existing ground-coil-based location system. (1) If the system loses its present location, this system can be restored in a second. In contrast to the existing coil-based system which cannot be restored until the next reference point. (2) This system is able to create an onboard database of the track automatically. The new position detection system combines three techniques to detect the train location, (1) use of a GPS system; (2) calculation of the cumulative running distance by a tachometer generator, which is fitted in order to measure wheel rotation; (3) curvature collation with the track database and the measured curvature during running. One of these techniques is selected by the reception reliability index value of GPS data. To check the precision of position detection using this system, We ran a train over many ground coils used for the automatic train stop system, detected their positions, calculated the average of the two measurements at each ground coil, and summarized the dispersion of measurements from the average as the errors in fixed-point detection. Test Results was that the fixed points detected by GPS alone spread in a wide range up to 34 m. In the present system, after changing the algorithm for processing detected positions depending on the reliability of GPS data, the detected positions were all in a 4 m range. As the allowable error for current tilt-controlled trains is about ±10 m, it has been confirmed that the position detection system using GPS has higher reliability than the existing system.