Indoor positioning methods are being developed, outdoor methods are in use for years now. It's how positioning works on your laptop, e.g. in Google Maps. http:

Indoor positioning methods are being developed, outdoor methods are in use for years now. It's how positioning works on your laptop, e.g. in Google Maps. http://en.wikipedia.org/wiki/Wi-Fi_positioning_system http://en.wikipedia.org/wiki/Wi-Fi_positioning_system "Commercial providers of this type of positioning service include Google,[1] Navizon, AlterGeo[2] and Skyhook Wireless."