Research And Design Of Underground Coal Mine Positioning System Based On UWB

With the improvement of coal mine safety construction,the positioning information of underground personnel and equipment in coal mines has become the basic information of safety construction,and it is developing in the direction of high precision and high real-time.Ultra Wide Band(UWB),as an emerging wireless communication technology,has the characteristics of high time resolution and strong resistance to multipath effects,and it is suitable for use in wireless positioning systems.Based on UWB technology,this paper studies and designs a high-precision positioning system underground in coal mines.In this system,the Asymmetric Double-Sided Two-Way Ranging(ADS-TWR)algorithm is used for the ranging between the base station and the tag to reduce the ranging error caused by clock drift,and use the joint positioning algorithm to reduce the positioning error,and use the two-dimensional area discrimination strategy to discriminate the area where the label is located,which can reduce a large number of invalid communication frames in the process of system positioning,so that improve the efficiency of positioning.At the same time,this paper designs the wireless ad hoc network communication method based on Long Range Radio(LoRa)and the method of using lithium battery power supply for the emergency use of the positioning system.To ensure the emergency use of the system.The specific works are as follows.This article first analyzes the current research status of UWB positioning technology at home and abroad,studies and analyzes several indoor positioning methods,discusses the positioning suitable for UWB technology,and selects the best positioning method based on the coal mine environment.This paper analyzes NLOS factors that affect the underground behavior,and adopts a joint positioning algorithm for this problem.First,the Weighted Least Square(WLS)algorithm is used to obtain the initial positioning coordinates,and then the BKF and the method of setting the residual threshold are used to eliminate the influence of NLOS,and finally use Unscented Kalman Filter to filter and track the positioning coordinates,which improves the positioning accuracy in the NLOS environment.Aiming at the problem of a large number of invalid communication frames,which is in the positioning process of the underground coal mine positioning system,this paper adopts a two-dimensional area identification strategy based on ADS-TWR.The tag can identify the current area based on the data returned by the current base station,and the tag only communicate with the base stations in this area.And on this basis,a two-dimensional area correction mechanism is used to achieve area correction and switch positioning areas.Aiming at the problem that the traditional underground coal mine positioning system cannot be used in emergency situations,this paper designs an emergency transmission method of positioning data based on the LoRa wireless ad hoc network in the positioning system.This method uses the self-healing,self-organization and self-adaptability of the LoRa wireless ad hoc network to ensure data transmission in an emergency environment.A backup lithium battery is designed in the positioning base station,so that the positioning base station continues to work when the power supply is cut off.Based on the above algorithms,strategies,and communication methods,this paper designs a UWB-based coal mine positioning system software and hardware platform,and uses this platform to simulate coal mine scenes to design the positioning system experiments,and analyze the experimental test results.This article includes 45 graphs,10 tables,and 72 references.