Currently, I am thinking that since electromagnetic waves loose energy over distance, you might be able to figure out the relative distance to each of three radio "beacons" and use this information to triangulate the position of a robot with a radio sensor on-board.
What information each radio signal could I use to measure the distance to correlating beacon? Amplitude, perhaps? The entire system would be running indoors in a relatively small area, so it needs to be relatively precise.
Is this even a reasonable idea, or are there better methods I could use?
Note: I asked a similar question about radio triangulation on the Robotics SE, where someone asked me to look into the Engineering SE instead.