Abstract: In view of wiring difficulties，low level of information and visualization problems about underground tramcar positioning system in tungsten mine，and in order to more reasonably and efficiently schedule tramcar，a real-time positioning and monitoring system of the tramcar based on ZigBee wireless network was proposed to realize underground positioning and safety monitoring on tramcars.RSSI ranging model for transferring wireless signal of ground environment was explored.Then，with the aid of Gauss filter，the RSSI ranging parameters were modified.Then，combined with the multilateral localization algorithm，the positioning was achieved.For large errors in the algorithm，the weighted centroid localization algorithm was proposed to improve the positioning accuracy.The underground tramcar speed and position information were real-time uploaded and well displayed on host computer.Through simulation experiments，the results demonstrated that the modified weighted centroid algorithm can effectively lower the positioning error，and the host computer can realize the transfer，storage，real-time display，query，and early warning and other functions.The system has the characteristics of real-time，high accuracy and good robustness，which can effectively improve the safety of production in tungsten mine.

Key words: ZigBee wireless network, Tungsten mine, Underground tramcar positioning, Received signal strength indication, Maximum likelihood, Weighted centroid