Superfast, subatomic-sized particles called muons have been used to wirelessly navigate underground for the first time. By using muon-detecting ground stations synchronized with an underground muon-detecting receiver, researchers at the University of Tokyo were able to calculate the receiver’s position in the basement of a six-story building.
Hold on a second … how accurate is this technique and is it usable as a non-disruptable, world-wide, no infrastructure required GPS system?
Edit: Broke my own rule of not commenting before reading the damn article. Up to 2m accuracy, maybe there is something there. Would be a new Galaxy Positioning System if usable.