Research On Wireless Localization Method Under NLOS Propagation Environment

With the increasing demand for precise localization,research on wireless localization technology has become a hot topic.In the actual wireless signal transmission process,the signal is inevitably affected by non-line-of-sight(NLOS)transmission during the transmission of the target point and the reference base station.Under the influence of this positive deviation,the measured localization parameters will seriously deviate from the true value,resulting in a significantly drop in the localization performance of the algorithm.Therefore,the main research content of this paper is how to improve the algorithm localization performance in non-line-of-sight environment to meet people's high-precision localization requirements.The main research contents of this paper are as follows: First,by studying the influence of the base station topology on the localization accuracy,we use the method of Geometric Dilution of Precision(GDOP)measurement to obtain the coordinate position of the virtual base station in the classical base station topology environment.Then,using the reference base station method proposed in this paper to obtain the virtual range which is from virtual base station to target node.Then the virtual base station is introduced into the traditional two-step weighted least squaresweighted least squares(TS-WLS)algorithm and the linear optimization(OPTLLOP)algorithm,and the localization performance of the algorithm is improved by optimizing the ranging value.The simulation results show that the proposed VBS method can significantly improve the localization accuracy of traditional algorithms.Thirdly,the collaborative localization algorithm is studied.The key of the algorithm lies in the choice of cooperative nodes.According to the research on the eigenvalues of the rigid matrix,this paper proposes a rigid cooperative node selection method,and selects the reliable cooperative nodes with small localization errors to participate in the localization.At the same time,the distance residual method is used to further eliminate some of the cooperative nodes,and the cooperative nodes with the smallest localization error value are retained.Then,through link detection,it is determined whether a cooperative node needs to be introduced,and if necessary,a cooperative node that satisfies the condition is introduced according to the detection result,and is upgraded to a reference node to participate in localization.The actual simulation results show that the localization performance of the proposed cooperative localization algorithm is significantly better than other comparison algorithms,especially in the harsh environment with large NLOS error value.Finally,the research work carried out in this paper is summarized,the shortcomings in the research are analyzed,and the future research directions and areas for improvement are pointed out.