Indoor NLOS Single Station Location Algorithm Based On Scatterer Information

At present,outdoor positioning technology has more and more prominent application value to people.For example,outdoor navigation,unmanned driving and so on all need location information.However,in the indoor environment,the performance of the satellite positioning system which is widely used outdoors is greatly reduced because of the blocking of satellite signals by buildings.In addition,in the Non-Line-of-Sight(NLOS)propagation environment,the accuracy of the direct wave positioning algorithms is greatly reduced in the vast majority of cases.In view of this,it is very necessary to study the positioning technology in the indoor NLOS environment.In order to achieve this goal,this thesis takes NLOS propagation path information as a favorable condition and proposes a localization algorithm in indoor NLOS environment.This method utilizes abundant scatterer position information and can overcome the time synchronization problem caused by multiple base stations.The main research contents of this thesis are as follows.Firstly,according to the characteristics of wireless signal propagation in the indoor NLOS environment,the Angle of Arrival(AOA)of the reflection path is used to determine the fuzzy range of the scatterer position,and the scatterer position is searched under this constraint condition.Secondly aiming at the phase error problem in the real wireless network,this thesis uses the Time of Flight(TOF)between the multipath signals to obtain the estimation location;In order to realize multipath assisted positioning without using the Angel of Departure(AOD),a TOF transmitted by a single base station and reflected by a scatterer to the target path is selected as a reference,and TOFs from other paths are differentiated with it to construct a differential TOF,so as to eliminate the phase error caused by the asynchronous receiver and transmitter;Then the differential TOF is used to construct the nonlinear positioning target equation,which is further transformed into a nonlinear least squares optimization problem.Then,in order to locate the target accurately,this thesis firstly uses the Genetic Algorithm(GA)to locate the target preliminarily.Then,the modified Gauss-Newton(GN)algorithm is used to perform the second precise positioning.Finally,the Affine Propagation Clustering(APC)algorithm is used to eliminate the position points with large errors,and the final convergent iteration result is taken as the target position.Finally,in order to verify the proposed algorithm,Matlab is used for the simulation,whose results show that the algorithm can effectively locate the target.Then,in order to verify the performance of the algorithm in a more realistic environment,this thesis uses the Wireless Insite software of RECOME company to simulate the proposed algorithm.The massive experimental results show that the proposed algorithm can achieve high positioning accuracy when there is no Line-of Sight(LOS)signal and only a single base station in the indoor scene.