Design And Research Of Personnel Positioning System In Tunnel Based On UWB

At present,China’s railway construction is developing rapidly,With the rapid development of construction,there are also higher requirements for the safety management of on-site personnel.Due to the particularity of the environment in railway tunnels,outdoor positioning technologies such as GPS cannot be used,so it is of great significance to study personnel positioning technology in railway tunnels.Commonly used indoor positioning technologies include Wifi,Zigbee,Ultrasound,and UWB.UWB positioning technology has the advantages of strong penetration,low power consumption,and multipath resistance,making it more suitable for applications in complex environments such as tunnels.Therefore,this p uses UWB positioning technology to develop a set of tunnel personnel positioning system based on UWB.Firstly,several UWB algorithms are studied.The commonly used positioning algorithms for UWB positioning technology include TDOA and TOF algorithms.The TDOA algorithm has strong positioning time performance and slightly weak positioning accuracy.The TOF algorithm has high positioning accuracy,but its positioning speed is relatively slow.Based on the two algorithms,a particle swarm optimization based TDOA+TOF fusion localization algorithm is proposed.This algorithm only requires three times of UWB communication to achieve positioning.The distance between each base station and the tag is collected through the TDOA algorithm.The TOF algorithm calculates the tag coordinates based on the least square method,and the particle swarm optimization algorithm optimizes the solution coordinates based on the objective function to obtain the most global optimal solution.The simulation analysis compares the positioning accuracy and time performance of TDOA,TOF,and TDOA+TOF fusion algorithms based on particle swarm optimization.The results show that the TDOA+TOF fusion algorithm based on particle swarm optimization combines both positioning accuracy and time performance,and can be well applied to human positioning in complex environments.Then,on the basis of theoretical research,the system implementation scheme is designed.The hardware design part includes the main control chip circuit,DWM1000 circuit,power supply circuit,smart helmet,etc.The software part designs the front-end interface of the upper computer platform,various user functions,the lower computer communication protocol,the base station and the tag to realize the distance measurement function process,and completes the overall scheme of the system.Finally,the system functions and positioning accuracy are tested on the spot by building a test environment.The function test results show that the initial coordinate setting of the base station,electronic fence alarm,alarm log recording and other functions of the positioning system meet the user requirements.The positioning accuracy test is divided into static test and dynamic test.According to the error analysis of the real coordinates and location coordinates of the test points,it is concluded that the overall positioning accuracy of the system can reach within 20 cm and can be applied to the field.