High accuracy track distance measuring system - has regularly spaced repeaters energised at different frequencies for error correction of locomotive distance measurement

摘要

The track-distance signalling and correction system consists of an inductive cable radiator laid the length of the track with a corresponding receiver and demodulator in the locomotive. At regular intervals along the track are distance markers comprising repeaters or transponders each of which is fed with a different low-frequency signal. The change of frequency at each repeater point is detected by the locomotive and this signal is used for error correction of the existing track-distance measuring system in the locomotive. Since the sequence of different frequencies detected depends on the direction of travel of the locomotive, this parameter also may be determined from this type of system.