Research On Key Technology Of WiFi Indoor Positioning

With the rapid development of mobile Internet,the requirements of positioning in indoor environments have become increasingly demanding.People often need real-time navigation and locate services in complex indoor environments such as super makets,exhibition halls,and underground parkings.WLAN-based technology has been a hot topic in the field of indoor positioning,because WLAN technology is widely deployed,cost less and convenient.The key technology of indoor positioning including indoor positioning algorithm and indoor map matching algorithm are investigated and studied deeply in this paper.In terms of indoor positioning algorithm,the mainstream indoor positioning technology-fingerprint positioning technology is investigated.This work collects the wifi data and analyzes the received signal strength in detail,including propagation,convergence and distribution characteristics,through the deployed wireless access points in real indoor environment.This paper also researches the optimal parameters and the factors that influence the postitioning performence.Fingerprint database might be invaild in the changing environment,for sloving this problem,dynamic fingerprint database is proposed and verified in this paper.In terms of indoor map matching algorithm,some common methods for indoor map matching algorithm are investigated.According to the characteristics of indoor environment,an indoor map matching method based on link table is proposed.This method establishes a link table to deposit the information of candidate links based on traditional map matching,and selects the most likely correct link from the link table when it needs. Due to the mechanism of error checking and recovering,this method can reselects the correct link from link table when the mismatching happens, The funtion of these mechanism make this method especially suitable for the complex indoor environments.Experimental results show that,compared with traditional map matching approaches,this method can obviously improves the map matching accuracy.According to these findings,this paper designs and realizes an indoor location software on the Android platform.On the basis of the requirements of indoor positioning,the softwareconsists of four parts,including UI,algorithm,wifi&sensor and fingerprint database module.The specific designs and the logical realationship of each module are explained in this paper.Installed in the smartphone,the software has a good performence.