Research On The Key Technology Of Indoor Location Based On WiFi Network

Location Based Services in the modern information society are becoming more and more common,it has placed a greater demand on location technology.The traditional location technology which is based on GPS can achieve civil 3 meters accuracy,but it is generally applicable to outdoor environment,in the complex indoor environment,it is difficult to achieve high precision.WiFi network widely exists in various kinds of buildings and houses,it has the advantages of high transmission speed,low construction cost,which make it competitive in indoors positioning system.And the popularity of smart phones provides equipment protection for WiFi Positioning Technology Development.This paper does research on the algorithm which is based on RSSI,especially does a thorough analysis of the position fingerprint identification algorithm which is based on clustering,aiming at the problems of low precision of the edge of the locating point,put forward a improved algorithm to improve edge localization accuracy.The main research contents and achievements are as follows:First,does a study on indoor positioning technology,make an analysis of WiFi technology and its location fingerprinting characteristics.Does a research on location calculation and signal measurement method.Analyzes the basic principle,off-line training,on-line matching algorithm of the location fingerprint indoor location algorithm,does research on the indoor signal propagation characteristics.Then does research on the basic principle and performance evaluation index of the K-means clustering algorithm.Builds the simulation model to measure the algorithm performance.As the k nearest neighbor algorithm,when k = 4,it gets the best positioning effect.Simulation results show that the traditional clustering algorithm gets larger error in edge location accuracy.So we put forward a improved algorithm to get high precision of the edge positioning point.We put the neighbor clustering into the positioning reference to improve the positioning accuracy of the edge points.The complexity of improved algorithm has increased slightly,but the mean localization error of the improved algorithm reduces by 17%.Finally based on the Android platform and Windows platform,this paper designs a C/S mode positioning systems,makes the detailed design respectively for the client and server side function,designs the communication protocol and data package,the improved algorithm is applied to the system.Builds experimental environment to evaluate the performance of the improved algorithm.The experiments show that,under the premise of no changing the accuracy of central positioning points,the improved algorithm has improved the accuracy of the edge points.