Real-time GPS based outdoor WiFi localization system with map display

There are many applications such as security, medical and rescue operations, sports events, and so on where one may need to find out the exact location of a transmitting wireless local area network (WiFi or WLAN) access point. In this paper, we look at the design of an outdoor WiFi localization system based on a GPS. This system utilizes a rotating unidirectional multi-element Yagi type unidirectional antenna to determine in real-time the direction of the maximum signal strength from a WiFi access point. This information is combined with the GPS co-ordinates of the measurement points to triangulate and find the exact co-ordinates of the access point. These co-ordinates are then transferred to the Google Earth application to automatically pin-point the access point on a world map. This is a novel application where once the user has issued the relevant command, the software will perform all necessary steps without interaction. This includes controlling the hardware, obtaining readings, performing calculations, and showing the location determined on a map. We present the theory and experimental results to illustrate the performance and accuracy of our outdoor localization system.