Research In Wireless Ranging Based On UWB And Vehicular Integrated Positioning Algorithms

The "Internet Plus" plan in the automotive industry includes the core content and direction of Internet of Vehicles(IOV).Vehicle positioning technology is one of the important supporting technologies of the IOV system.The accuracy of vehicle positioning is related to the practical value and overall performance of the IOV system.Currently,vehicle positioning relies on the GPS.The positioning accuracy of the GPS system is high,but the location area is limited.In tunnels,underground parking lots and other places,the positioning performance is easily affected by the non-line of sight(NLOS)environment.The reliability of the single system is reduced and the positioning demand of the IOV cannot be satisfied.This paper aimed at the accurate location of vehicles in complex environment,and studied the ultra-wideband(UWB)short-range wireless transmission communication technology,and designed a positioning algorithm based on UWB technology.The main contents are as follows:1.The principle of UWB positioning technology is described in detail from the aspects of pulse waveform,channel model,signal correlation detection and ranging technology.2.Analysed and derivated the least squares algorithm,the Chan algorithm and the Taylor algorithm,and compared the Chan-Taylor co-location algorithm did performance simulation;For the traditional algorithm sensitivity to the initial coordinates,the vehicle relative position estimation problem is transformed into a nonlinear programming problem Combining external penalty function method and variable-scale algorithm,this paper proposes a Free Coordinate Localization(FCL)algorithm that does not depend on the exact initial coordinates.It used residuals to determine weights to introduce the fusion model algorithm to avoid the incidental error of single model;an algorithm based on BP neural network is introduced to correct the Time Of Arrival(TOA)measurement value,which slows down the influence of the NLOS environment on the positioning algorithm.Simulations were performed on the above algorithms.3.Build indoor and outdoor collaborative positioning system.Combining the GPS positioning system with the UWB positioning system,the two systems have complementary advantages and can realize integral and continuous positioning during vehicle driving.The simulation results show that: 1.The improved algorithm has improved positioning accuracy under various performance influencing factors.It can achieve centimeter-level positioning and satisfies the positioning requirements of road level(1m-3m).2.The iterative algorithm is more adaptive to noise environments.3.The algorithm based on BP neural network can effectively reduce the influence of NLOS environment.