POSITIONING SYSTEM FOR DIGITAL TELEPHONE NETWORKS

摘要

The invention relates to determining the position of a mobile receiver (4) in a digital telephone network positioning system. A first receiver (3) is at a known location and others are mobile. The method involves transmitting signals from a plurality of sources (1), the transmission signals having a format at least a portion of which has predetermined values or a portion of which is repeated. The time offset of the transmission signals received at each receiver (4, 5) from a transmission source (1) relative to a reference clock of each receiver is determined by generating a reference signal locked to the reference clock. The reference signal has a similar format to the transmission signals and includes a portion identical to the predetermined values or repeated portion of the received signal and compares the received transmission signal and the reference signal. The time delay between the respective signals received at the receivers (4, 5) is determined from their relative time offset, to thereby determine the position of the other receivers (4).