Multipath Assisted Indoor Positioning Method Based On Mirror Virtual Base Station

With the development of social information,positioning technology has become an indispensable part of related services in the areas of national defense,emergency rescue,and monitoring.However,due to the relatively complex indoor environment,in the positioning method based on TOA and AOA,the signal propagation process between the transceiver ends is seriously interfered by the multipath effect,which increases the received data error.Thus positioning accuracy of the positioning system will have a negative impact.The existing method of reducing the error has the problem that additional base stations need to be deployed or the conditions of use are severe.In an indoor environment,the path length of a multipath component reflected from a fixed wall surface is the same as the path length of a direct path emitted by a mirrored virtual base station obtained by the physical base station using the wall surface as a reflective surface.Using this reflection mirror analysis method,combined with the prior information such as the model of spatial propagation of the signal and the geometrical plan of the building,we can use the additional spatial information brought by these multipath components to improve the positioning accuracy under multipath propagation conditions.This dissertation analyzes the current channel and propagation mechanism of indoor signals,studies the reflection characteristics of UWB signals,and explores the feasibility of the algorithm based on the reflection characteristics of the UWB signals.It proposes an improved model that uses indoor environment map information and multipath information for positioning.The main contributions of this dissertation are as follows.(1)Based on the analysis of the wireless channel model and the reflection mechanism,the establishment rule and positioning model of the first-order mirror virtual base station based on multipath information are given first.Based on this,the second-order image virtual base station and high-order image virtual base station expansion methods are deduced.(2)For the incomplete condition of multipath information,the probabilistic parameters of the algorithm are modeled according to the different types of signal fading,and an improved method for estimating the probability of replacing the empirical parameters by Poisson process estimation is proposed.The accuracy of mirrored virtual base station positioning increases by 6.25%under a single base station condition.(3)dissertation The characteristics of probability distribution of the location to be measured under single base station multipath information location method is analyzed in this dissertation.A method of location estimation probability of multipath information combined with a priori location information is proposed.Under the simulation condition that there is a positioning source with an average positioning error of 1m,the accuracy of a single base station is improved to 0.58m.(4)Based on the priori obstacle shape information and wall material information,a method for generating probability distribution based on prior information of obstacles and walls was proposed,and a joint probability base location algorithm for mirrored virtual base stations under multi-entity base stations was proposed.In the simulation environment of the dual-substrate base station,the average positioning accuracy is 0.25m,which achieves the accuracy level of the three physical base stations of the traditional positioning method,and saves the deployment cost of the.physical base station.To sum up,in view of the problem of indoor multipath effect,this paper proposes to use the reflection components in indoor multipath for indoor positioning.This alleviates the shortage of using the existing methods and the high cost of the base station deployment,and finally improves the indoor positioning accuracy.