kddi seems to have tried to employ bluetooth to replace gps (gosh!) indoors. the idea is that you put bluetooth beacons which beam maps of the area you are in to you. i guess then what happens is that using proximity, and the fact we know where the bluetooth beacon is, therefore you can be able to "guess" where you are.
not sure how reliable that is, i guess this thing we're working on about bluetooth signal stregth measurements might let us know.
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