Passive bluetooth devices can be used for very accurate indoor positioning. In fact, I'm looking to set up a bluetooth LE beacon based positioning system at ho

Passive bluetooth devices can be used for very accurate indoor positioning. In fact, I'm looking to set up a bluetooth LE beacon based positioning system at home to detect when I move between rooms and switch things like fans/lights/music. Over a decade ago when I was in university there was practical experimentation going on into this form of indoor positioning (it was a project option in undergrad EEE), these days it's a done deal.