TOF underground accurate positioning technology based on message multiplexing

In view of problems that symmetric-double-sided two-way ranging (SDS-TWR) method had low ranging efficiency and poor expansibility and there was still room for improvement in the ranging efficiency and positioning system capacity of asymmetric-double-sided two-way ranging multi-ack(ADS-TWR-MA)method in current ultra-wideband TOF underground accurate positioning technology, a method of asymmetric-double-sided two-way ranging multi-tag multi-anchor (ADS-TWR-MTMA) was proposed. On the basis of ADS-TWR-MA method, the method further multiplexes ranging message in asymmetric-double-sided two-way ranging process, so that multiple tags and multiple anchor nodes can be used for TOF ranging simultaneously. The method greatly improves ranging efficiency and capacity of positioning system under premise of ensuring ranging accuracy. The application in locomotive proximity detection system and accurate positioning system verifies that the ADS-TWR-MTMA method is superior to SDS-TWR method and ADS-TWR-MA method in number of ranging messages, ranging time and system capacity.