Research On Mine Personnel Positioning System Based On ZigBee Technology

In recent years,with the rapid development of science and technology,a variety of positioning technology has been used in the coal mine personnel positioning system.Because of the hardware limitation and unreasonable location method and so on,the traditional positioning system has poor positioning accuracy,can't complete real-time positioning and difficult to monitor.The localization technology based on signal intensity was selected and the coal mine wireless network was built with ZigBee technology.Taking CC2530 chip as the central part and combining several localization algorithms a set of high-precision mine personnel positioning system with real-time positioning function was set up.The systems functions include real-time positioning of personnel,attendance system,alarm system,self-test,data compression,storage,and so on.The main contents are as follows:(1)Aiming at the problems existing in traditional positioning systems,a new mine personnel positioning system was designed according to the latest national standards and the new functional requirements.In the hardware part,the circuit systems of wireless nodes including of the positioning sub-stations,the mobile nodes and reference nodes were designed..In the software part,the software systems of the upper computer and all kinds of wireless nodes were developed and the communicating protocol between each positioning sub-station and the upper computer was completed.The upper computer software supports several localization algorithms including of RSSI fingerprint algorithm,trilateral algorithm and grading algorithm.Besides,RSSI fingerprint algorithm supports multiple matching algorithms.The upper computer software allows different location algorithms to be used in different positioning areas at the same time,so that the managers can change the location algorithms according to environments flexibly.(2)A new location algorithm,the grading algorithm,was proposed based on the improvement on trilateral algorithm and RSSI fingerprint algorithm.Grading algorithm is a substitute of trilateral algorithm.The location can be carried on with the shadowing model of radio propagation model in grading algorithm.It can not only achieve high positioning precision,but also provide the estimated value of location error.(3)Aiming at reducing random error in positioning,Kalman filtering was used to assist the positioning.The adverse effects caused by random error can be reduced effectively and the positioning accuracy of the system improved with Kalman filtering.Kalman filtering is suitable for grading algorithm to assist positioning.In grading algorithm,the positioning error can be estimated.The parameters of Kalman filtering can be adjusted according to the positioning error,which can reduce the positioning error caused by system random error effectively.(4)Trilateral algorithm,RSSI fingerprint algorithm and grading algorithm were tested.It was shown that the positioning accuracy of grading algorithm is the same with RSSI fingerprint algorithm,but the grading algorithm has better flexibility.The positioning accuracy of grading algorithm is 30% higher than that of the trilateral algorithm.The average positioning error of grading algorithm is about 1.2 meters.In harsh environment,the positioning accuracy of grading algorithm is about 60% higher than that of the traditional trilateral algorithm and the average positioning error is about 2.3 meters.