Mitsubishi uses sound and WiFi to locate you indoors
 

There have been many attempts at locating you indoors when GPS fails, but they usually come with catches. WiFi alone isn't very accurate, for example, while a ton of beacons isn't always practical. Mitsubishi may have a good answer to those problem...

http://www.engadget.com/2016/02/12/m...door-location/