Research On The Precise Indoor Differential Positioning Technology Based On UWB

As people spend more and more time indoors,the demand for indoor positioning is increasing.The traditional outdoor positioning techniques,such as GPS and Mobile phone positioning,are not able to meet indoor positioning requirements due to the shelter of buildings and the complex indoor environment.Although there have been WiFi positioning,Bluetooth positioning,ZigBee positioning and other indoor positioning techniques,but the actual positioning effect of them is not very ideal.The UWB(Ultra Wideband)positioning system has the advantages of high positioning accuracy,low power consumption,low cost and strong multipath resolution.It can achieve centimeter-level positioning accuracy theoretically.Therefore,compared with other indoor location technologies,UWB positioning technology has great advantages,which makes it become a hot topic in the research of precision indoor positioning technology.In order to improve the positioning accuracy and stability of indoor UWB positioning system,this paper has carried out the research on the indoor differential positioning technology based on UWB,and focused on the UWB indoor differential positioning algorithm and the improved Kalman filtering algorithm.First,based on the study of some indoor positioning algorithms,the TDOA positioning algorithm is selected as the basis of the UWB indoor differential positioning algorithm.In order to solve the influence of imperfect clock synchronization on the TDOA positioning algorithm,this paper proposes an UWB indoor differential positioning algorithm based on the differential clock correction model.Then,in order to solve the influence of outliers on the filtering process,this paper propose an improved Kalman filtering algorithm.It add the measurement of outliers and the correction of innovation,so that it can better satisfy the filtering requirements of the UWB indoor differential positioning algorithm.We use MATLAB to simulate the improved Kalman filtering algorithm and the simulation results verify its theoretical feasibility.Finally,in order to verify the effect of UWB indoor differential positioning algorithm for imperfect clock synchronization,we used Hainan EVK 2.0 to do some tests.The test results show that UWB indoor differential positioning algorithm can effectively eliminate the influence of imperfect clock synchronization,reduce the positioning error and the fluctuation range of the positioning error,to make the positioning more stable.