JP2010177982A5 - - Google Patents

Claims (3)

The digital train base station more to respond base station sac Chi pairs included in the wireless system, a reference timing signal for performing digital communication between the onboard mobile station to the train, and supplies via the transmission path A GPS1PPS signal correction device for correcting a delay of the reference timing signal caused by the transmission path,
A transmission unit that outputs a timing signal corresponding to the reference timing signal to the transmission path;
A receiver that receives the timing signal output from the transmitter via the transmission line and outputs the signal to the corresponding base station;
The receiver is
Timing signal return means for sending back a part of the timing signal received via the transmission path to the transmission unit via the transmission path;
The transmitter is
A reference timing signal generating means for generating the reference timing signal at a constant time interval;
Each of outputting the timing signal to the transmission path, from outputs the timing signal, to a part of the timing signal is sent back through the transmission path I by the timing signal responding means A time measuring means for sequentially measuring the round trip time;
Each time the round trip time is measured by the time measuring means, the timing signal is generated prior to the next generated reference timing signal by half the measured round trip time. A GPS1PPS signal correction apparatus comprising: a timing correction unit that outputs a signal to the transmission line as a timing signal corresponding to the reference timing signal generated next . The reference timing signal generating means includes
Receiving data transmitted from GPS satellites, based on the data thus received to generate a pulse signal of 1-second intervals, the pulse signal thus generated to claim 1, characterized in that the output as the reference timing signal The GPS1PPS signal correction apparatus described. Each time the reference timing signal is generated by the reference timing signal generation means, the time until the timing signal corresponding to each reference timing signal is sent back by the timing signal return means is sequentially measured and measured. number of time exceeds the predetermined time is, in case of exceeding a predetermined number continuously, according to claim 1 or 2, characterized in that it comprises an abnormality informing means for informing an abnormal GPS1PPS signal correction device.