Research On Underground Positioning System Based On UWB Technology

Coal is closely connected with the development and progress of our society.At present,the positioning system of underground precise location still has the problems that it is unable to obtain the location information more accurately,it is easily affected by external factors,and the ability to detect the location information of underground objects is weak.Therefore,it is of great significance to study a more precise positioning system to improve the safety of coal production in my country and reduce casualties.This paper first analyzes the current research on the positioning protection system of coal mine production personnel in the world and my country,and summarizes the advantages of ultra-wideband(UWB)technology in downhole positioning.Then it is proposed to combine the weighted least squares with Kalman filtering,and the experimental results show that the combined position estimation error is smaller,which greatly improves the estimation accuracy and stability.In order to solve the problem that the noise covariance matrix cannot be updated online and the accuracy of distance measurement is low due to many non-line-of-sight(NLOS)interferences in the wireless range,the Sage-Husa adaptive filtering algorithm is improved to greatly improve the accuracy of the distance measurement.This paper also proposes a TOA algorithm based on wavelet threshold denoising.Experiments show that the coordinate value of the mobile tag obtained by combining the traditional TOA algorithm with the wavelet threshold denoising algorithm greatly reduces the error range compared with the actual measured coordinate value.It is concluded that the wavelet threshold denoising algorithm can indeed significantly improve the accuracy of UWB positioning,and the algorithm is used in the underground positioning system.Finally,the software and hardware of the positioning system are designed and tested.