Research On Positioning System Of Inspection Personnel In Subway Train Maintenance Depot Based On UWB

Subway trains need to be returned to the depot for inspection after being shut down.So the inspectors need to carefully check the subway train according to the process.As the inspection of subway trains are mostly carried out in the middle of the night,the inspectors will suffer from slackness and other violations of the maintenance process.In order to better record the inspection process of inspectors,the design of a set of indoor positioning system based on the combination of UWB technology and INS to obtain the position of inspectors during the inspection process is instroduced in this paper,whether the inspector completed the operation in accordance with the regulations was judged by the system positioning results.Firstly,according to the analysis of the subway maintenance depot environmental characteristics and the needs of the inspectors positioning system,the positioning scheme with " Microdevice(Tag+Anchor)+Host computer " is given.A algorithm combining UWB and INS is used to reduce the impact of NLOS.A NLOS recognition method was used to screen out the TOA information under LOS for the TOA algorithm.When the number of TOAs in the LOS is less than three,a tight combination fusion algorithm of UWB and INS based on EKF is used for positioning.Secondly,a positioning system hardware is designed which consists of a high-performance and low-power embedded processor STM32F103,an ultra-high time resolution UWB chip DW1000,and an easy-to-develop micro-inertial measurement device MPU6050.The system hardware has the advantages of small overall size,low power consumption,good portability,and high positioning accuracy.Then,the software&algorithm development scheme established based on ".NET Framework4.0 + C # + MALAB",which leveraged.NET’s convenient desktop application development,MATLAB’s powerful mathematical calculation capabilities,and C # language good compatibility features,it efficiently completed the software algorithm design of the system.The simulation verifies the positioning accuracy of the system and the effectiveness of the designed algorithm in the LOS environment and the NLOS environment.Finally,the performance of the inspectors positioning system based on UWB and INS was verified through experiments in the subway maintenance warehouse.The system error was within 15 cm under LOS and 0.8m under NLOS.