3D location from multiple cameras or an FM radio array
I've had the idea recently to attempt to be able to keep a real-time track of the location of something in a room.
My first thoughts where to use an array of FM receivers and a transmitter to triangulate the location of the transmitter, or maybe even bluetooth, but the test room is about 5 metres square, so bluetooth might be unrealistic.
As for the FM method, I think that could genuinely work, what do you think?
An idea also floated is to triangulate using an array of cameras, maybe all triangulating the location of one infra-red LED light.
What do the geniuses of Instructables think of the ideas here, do you think any are valid?