Status and prospects of research on positioning of targets in underground coal mines

This paper summarizes various positioning techniques developed recently years of targets in underground coal mines namely is underground positioning technique based on iBeacon, underground dynamic positioning technique based on Kalman filter UWB, positioning technique based on WMSNs video miner’s lamp, positioning based on TWR and SDS-TWR, positioning technique of personnel in underground coal mine based on asynchronous time-measuring, positioning technique of personnel in underground coal mine based on multi-sensor information-fusion, positioning technique of personnel in underground coal mine based on GRPM, positioning based on improved UWB algorithm and positioning of strap-down inertial navigation system and so on.And the aspects that degree of accuracy of positioning affected by the laneways and their supports and the conductors and obstacles existed in the underground laneways, whether the clock synchronization between the base station/mobile terminal and the reference station is required or not, whether the clock synchronization among the reference stations is needed or not, degree of accuracy of positioning affected by the frequency offset of the base station/mobile terminal and the reference station, cost of base station/mobile terminal and reference station that positioning accuracy are comprehensively evaluated for the advantages and shortcomings of the variety of positioning techniques.Research and development of new combined underground precise positioning systems to guarantee that transmission signals not be affected by the underground laneway surroundings and that the positioning systems don’t need clock synchronization and have these advantages namely is small positioning equipment complexity, low construction cost of base stations and reference stations, high positioning accuracy, and visualization of positioning and navigation are the key links to make the precise position service, precise control of underground targets management and mature intelligence of coal mines come true.