Research And Implementation Of Mine Personal Positioning System Based On Wireless Sensor Network

China has abundant coal resources, but the coal mine environment is so complex that accidents have occurred frequently.It's hard for the existed underground RFID person management systems to realize the location of person who work underground timely and accuratlly, but it's so important to konw the present location and situation of people who work underground to ensure their safty. Based on this background, a kind of mine personnel positioning system is proposed using Wireless Sensor Network(WSN).The safty level can be improved effectively and the loss brought by accidents can be reduced by timely getting the location of mine personnel.According to the characteristics of coal mine environment,a kind of mine personnel positioning system based on WSN is designed, including system structure, management mechanism and operation mode.Firstly, a kind of WSN location algorithm based on Received Signal Strgenth Indication (RSSI) is proposed.By utilizing the feature that the coordinates of reference nodes and the distances between them are known, the algorithm can compensate the coordinates of mobile nodes and improve the positioning accuracy. Experiments were to examine the performance of proposed algorithm, and results stated that the proposed algorithm can effectivly improve the location accuracy compared to common location algorithm,Secondly, according to the characteristics of coal mine environment, and the demands of reliability and timeliness of mine personnel positioning, a kind of underground positioning system was designed, and system composition and work mechanism were introduced.In order to decrease the location delay and management complexity of system,the style of using a lot of small WSNs to make up a big location system was proposed,and the nodes handoff scheme between WSNs was designed.Thirdly, to enhance the stability and realibility of system, a kind of system management mechanism was designed.By managing the reference nodes and mobile nodes, the network can work stably and the self-detection and warning capability can be greatly improved.At last, complete tests and performance analysis of mine personnel positioning system were carried out in laboratory environment,including functions of location, handoff between WSNs,system management mechanism,gateway switch-on ability and computer monitoring center.Tests results showed that system can achieve the desired function and carry out real-time location of underground personnel, and system management mechanism can ensure system work stability.Test results show that the design is reasonable and scientific.