Research On The Issues Of Analysis And Suppression Of NLOS In Wireless Localization

In the recent years,with the rapid development of mobile Internet,wireless positioning technology and location based services,such as vehicle mobile communication service,have received extensive attention.At the same time,various services and standards have put forward new requirements that wireless location algorithm should obtain results that meet the requirments of precision in complex real environment.In real wireless environment,there will be a variety of obstacles in the transmission path from the mobile station to the base station,so the signal would be reflected and refracted to reach the receiver.After reflection and refraction,the distance that the signal going through is longer than the line distance between the mobile station and the base station,and the angle of arrival of the signal base station received would have a large deviation.This phenomenon is called the non line of sight transmission.If the location of the mobile station is estimated by the parameters measured in the NLOS transmission,the accuracy of the estimation would be difficult to meet the requirements.For this reason,this paper studies the characteristics of the non line of sight transmission and its influence on the location algorithm,and studies the wireless location algorithm to detect and suppress the influence of the non line of sight error.Firstly,the signal propagation model in NLOS/LOS environment was studied by investigate research literature.This paper introduces the classical NLOS error model,and analyzes the influence of NLOS on the traditional positioning algorithm,and the differences of the geometric parameters used in the traditional algorithm between the LOS and NLOS environment.Secondly,by investigate previous work,we found that some results obtained in the actual environment will change with the change of the non sight distance error.Based on that,a method is proposed to obtain the relative size of the non line of sight error by using the Caley-menger matrix,and based on the results.Combined it with the traditional optimization algorithm by the lagrange multiplier method.The simulation results show that these algorithms perform better than the traditional related location algorithms.Then,the relative information of the non sight distance error between the different base stations was extracted and further used to obtain more accurate values of the non sight distance error by using the analytic hierarchy process,and the more accurate distance measurement values can be reconstructed by the result.Finally,by modeling the location into optimization problem,a wireless location algorithm based on the optimization theory is proposed.This algorithm is based on the special case of Caley-menger matrix,taking the area residuals as the objective function,and the geometric relationship of station as the constraint condition.The coordinates of the mobile station can be obtained by searching the feasible region.The simulation results show that such algorithm has a good perform in NLOS environment.