Patent ID: 6373434
Filing Date: 2002-04-16
Classification: G01S

Abstract:
A method for detecting a distance between a communication station and a target station in a CDMA system, the method comprising:transmitting a first periodic information signal from the communication station to the target station, so as to detect a first phase difference at the target station, wherein said first periodic information signal is generated with reference to a clock generated by a timer of the communication station, and said first phase difference represents a time difference between a first reference time based on a clock generated by a timer of the target station and a detection time of the first periodic information signal at the target station; receiving a second periodic information signal at the communication station transmitted from the target station upon receipt of said first periodic information signal, so as to detect a second phase difference at the communication station, wherein said second periodic information signal is generated with reference to the clock generated by the timer of the target station, and said second phase difference represents a time difference between a second reference time based on the clock generated by a timer of the communication station and a detection time of the second periodic information signal at the communication station; detecting a difference between the timer of the communication station and the timer of the target station by use of said first phase difference and said second phase difference; and detecting the distance between the communication station and the target station by use of the detected difference of the reference times of the timers and at least one of said first phase difference and said second phase difference, wherein said first periodic information signal and said second periodic information signal each transmit information used to detect a distance as well as information other than information used to detect a distance.