Patent ID: 7439904

Claim:
A ranging system comprising: a transmission signal generator which is configured to generate a transmission signal, formed of a chaotic signal, which is transmitted from a transmission device to a reception device; a correction signal generator which is configured to convert the transmission signal, which is processed in the reception device and re-input to the transmission device, into a correction signal; a reference signal generator which is configured to generate a reference signal to be compared with the correction signal, the reference signal having a certain frequency difference from the transmission signal; an overlap detector which is configured to detect a pulse region where the correction signal and the reference signal overlap each other; a time calculator which is configured to calculate a transmission time of the transmission signal between the transmission device and the reception device, using at least one among a time from the transmission of the transmission signal from the transmission device until right before overlap of a returned transmission signal and the correction signal, a time from the reception of the transmission signal at the transmission device until right before overlap of the correction signal and the reference signal, and a time while the correction signal and the reference signal overlap each other; and a distance calculator which is configured to calculate a distance between the transmission device and the reception device using the transmission time and a transmission rate of the transmission signal.