The human positioning system based on the WiFi Direct and Precision Time Protocol

Under the harsh environment and special geological condition, the technology in the home market at present when used in the coal mine can´t fulfill the need of the accurate positioning and tracking of the miner appropriately. For example, the RFID technology, which is popular in the most of Chinese colliery industry monitoring and location systems, just acts as an attendance system. The system can´t exactly pinpoint the miners trapped in the underground when the accident happens. And WiFi location applied in the underground location also has its limitation that was born with the low precise accuracy. The CDMA indoor GPS system can work well in the underground environment, but it is too expensive for the large-scale popularization in the major coal mines. For the reasons of all of the above, we suggest that the developers and engineers should develop a system with the characteristics of good stability, high locating accuracy and low cost in the large-scale extension and so on. This is the purpose of the paper; we propose to combine the IEEE1588 Precision Timing Protocol (PTP) with WiFi Direct system. With the use of the Time of Arrival (TOA) measurement of distance algorithm, we can achieve the goal of wireless real-time location and miner tracking.