The Wi-Fi hotspot database gets filled by correlating mobile device GPS location data with Wi-Fi hotspot MAC addresses. The accuracy depends on the number of nearby access points whose positions have been entered into the database. Typical parameters useful to geolocate the wireless access point include its SSID and MAC address. The most common and widespread localization technique used for positioning with wireless access points is based on measuring the intensity of the received signal ( received signal strength indication or RSSI) and the method of 'fingerprinting'.
Wi-Fi positioning takes advantage of the rapid growth in the early 21st century of wireless access points in urban areas. Such systems include assisted GPS, urban positioning services through hotspot databases, and indoor positioning systems. It is used where satellite navigation such as GPS is inadequate due to various causes including multipath and signal blockage indoors, or where acquiring a satellite fix would take too long. Wi-Fi positioning system ( WPS, also abbreviated as WiPS or WFPS) is a geolocation system that uses the characteristics of nearby Wi-Fi hotspots and other wireless access points to discover where a device is located.
