Research And Implementation Of WLAN Indoor Positioning Technology

As the rapid increase of multimedia service and data business caused by thedevelopment of mobile industry and the quickly expansion of the coverage ofwireless network on a global scale, people are having a growing demand ofnavigation and position in daily life.In some complicated indoor environment, such aslibraries,supermarkets and exhibition etc.the holders of mobile deviceoften need toget the position information in the current indoor environment, so achieving newbreakthroughs in indoor location technology and launching good indoor locationsystem will have important implications for the information of people’s daily life.Wireless Local Area Network (WLAN) has been widely deployed for itsadvantage of wide coverage, high speed transmission and low construction cost.Nowmost mobile device has a build-in wireless card, the indoor location technology basedon Wi-Fi has been paid wide attention. The basic principle of positioning in Wi-Finetwork is to detecting wireless signal strength and matching it with related positioncoordinate and obtaining the user’s estimated location.This dissertation gives an introduction of basic Wi-Fi technology at first, focuson the positioning technology based on RSSI (Received Signal Strength Indicator).Then take an analysis of positioning technology that could be deployed in Wi-Finetwork and an indoor positioning system based on Android operating system hasbeen developed. The main method for positioning estimate that the system adopted isRSSI technology. After an analysis of classic positioning algorithms, we present apositioning algorithm that based on fuzzy set by introducing the fuzzy set theory tothe estimation of position. The algorithm takesan reference point as a fuzzy set andestablish its member function. For the point that need to be positioned, the algorithmwork out the degree of membership of every reference point fuzzy set that surroundedwith the locating point and take the value of the degree of membership as weight tocalculate the weighted average of the coordinate of the surrounded reference points,finally take the weighted average of the reference points’coordinate as the established coordinate of the locating point.Practice shows that the algorithm is simple and hashigher accuracy and important value.