Mine TOA ranging method based on re-spread spectrum to WiFi signal

TOA ranging method requests high precision time measurement while existing mine WiFi systems can not provide high temporal resolution timer. In order to resolve the above technical problems, a TOA ranging method using re-spread spectrum technology to WiFi signal to obtain high resolution was proposed. Multi-carrier spread spectrum modulator is integrated into WiFi mobile station which is used to spread spectrum for ranging WiFi signal. Correspondingly, multi-carrier spread spectrum demodulator is integrated into WiFi base station, and a spread spectrum code capture algorithm with high speed digital matched filter designed by FPGA is used to capture ranging signal sent by the WiFi mobile station in sub-chip level, thus, the signal propagation delay time with high resolution is obtained. The test results show that the proposed method can provide reliable ranging data with mean-error of 1.92 m for TOA positioning of WiFi communication system.