As I understand it, the technique used is to create a map of the room by listening and recording all RSSI from all stations and training classifiers. Then the a

As I understand it, the technique used is to create a map of the room by listening and recording all RSSI from all stations and training classifiers. Then the app listen to all stations, input the RSSIs, and the classifiers give you back a location in the room. So the iPhone is supposed to just passively listen, not emit any signal – but apparently you can't access all RSSIs values of your surrounding stations via public APIs on iOS. In any case, it's a clever way to map the room by its spectrum landscape :-)