Patent ID: 9266543
Filing Date: 2016-02-23
CPC Classification: B61L,G01S

Claim Text:
1. A train protection device that decides a position of an own train on a track by using GPS satellites, the train protection device comprising: a GPS reception unit that identifies a position of the own train based on a GPS signal received from GPS satellites and outputs the identified position of the own train with information of a reception state value indicating a reception state of the GPS signal from GPS satellites at a time when the GPS signal is received; a tachogenerator unit that detects a running distance from a reference position of the own train and a current speed of the own train based on number of wheel rotations of the own train and outputs the running distance and the current speed; a track-information storage unit that associates a latitude and a longitude with information of a track on which the own train runs and stores therein associated information; and a position decision unit that decides a position of the own train based on the GPS signal, the reception state value, the running distance from the reference position, the current speed, and the information of a track on which the own train runs, and the position decision unit compares the reception state value to a threshold for determining accuracy in the position of the own train based on the GPS signal, wherein when the reception state value is equal to or larger than the threshold, the position decision unit decides a position as a current train position by adding, with respect to a forward direction of the track on which the own train runs, a correction value calculated based on a state of the own train to the position of the own train based on the GPS signal, and when the reception state value is smaller than the threshold, the position decision unit decides a position as a current train position by adding, with respect to the forward direction of the track on which the own train runs, the correction value to a position obtained by accumulating the running distance with respect to the reference position.