| As wireless communication technology and mobile devices develop well,indoor positioning service has gradually become an important content in the production and livelihood of modern society.In recent years,UWB positioning technology has emerged from many indoor positioning technologies with its powerful performance,and has gradually grown into an ideal solution in the field of indoor positioning.However,in the indoor NLOS environment,UWB positioning technology will have some problems such as low accuracy and bad stability,hence it is difficult to meet the high indoor positioning accuracy requirement.INS is an extremely independent navigation system that can realize indoor positioning alone,and it is not affected by the NLOS environment,but there is a phenomenon of error accumulation in the INS.Under this premise,by combining UWB positioning technology with INS,this paper realizes the complementary advantages of UWB positioning technology and INS,thereby improves the system positioning performance and robustness.The specific research works are as follows:(1)In the UWB positioning section,firstly,the main reasons of UWB positioning error were analyzed;secondly,the DS-TWR algorithm was introduced to solve the problem of ranging error caused by the unsynchronized clocks between the base station and the tag in UWB positioning;thirdly,the least square method and Taylor series method were used to solve the coordinate information of UWB positioning.Finally,a UWB positioning experiment was carried out,the experimental result indicates that the NLOS environment seriously affects the positioning accuracy of UWB.(2)In the INS positioning section,to solve the problem that the INS cannot successfully complete the positioning due to the error accumulation phenomenon,an INS optimization framework based on the EKF was designed.The framework first detects gait through the generalized likelihood ratio detection algorithm,and then uses the ZUPT algorithm,the ZARU algorithm,and the HDR algorithm to initially eliminate the accumulative error of INS.INS positioning experiment shows that the positioning accuracy of INS optimized by this framework is significantly improved.(3)In the fusion positioning section of UWB and INS,to solve the problem that UWB is easily affected by the NLOS environment and the INS has accumulative error,a UWB＿INS fusion positioning scheme based on ISRUKF was proposed.This scheme takes differences between the UWB pseudorange information and the distance measured by the INS position relative to the UWB base stations as the observation vector,and then merges it with the system state error vector in a tight combination,which effectively reduces the interference of the NLOS environment on UWB positioning and the influence of the accumulative error on INS positioning.The UWB＿INS fusion positioning experiment based on ISRUKF reveals that ISRUKF improves the positioning performance by 9.48% and 5.49% respectively compared with the traditional EKF and SRUKF,it has a better filtering effect. |
