| 摘要 |
PURPOSE:To eliminate the necessity for installing a plurality of dead reckoning devices corresponding to a plurality of GPS receivers, by combining a plurality of GPS (global positioning system) receivers with a dead reckoning method, measuring a position of a train and improving a measuring frequency by the GPSs equivalently. CONSTITUTION:A dead reckoning operation is carried out for a forefront position of a train by a dead reckoning operational device 33. The result of at least total length of the train is stored on a locus memory device 34. When either a front GPS 11 or a rear GPS 21 becomes unable to measure a position, a position difference operational device 35 obtains a position difference between the forefront position and a rearmost position of the train based on the locus stored on the memory device 34. A front position operational device 40 or a rear position operational device 50 corrects by the position difference an output of the GPS receiver which is unable to detect the position. If both of the front and rear GPSs 11 and 21 are turned inoperable, a dead reckoning device 30 executes the dead reckoning operation starting from the forefront position immediately before the GPSs are turned inoperable. |
