Image: Hiroyuki K.M. Tanaka
By using muon-detecting ground stations synchronized with an underground muon-detecting receiver, researchers at the University of Tokyo were able to calculate a receiver’s position in the basement of a six-story building without requiring GPS signals. The muometric positioning system (muPS) team was led by Hiroyuki Tanaka.
As GNSS cannot penetrate rock or water, muon technology could be used in future search and rescue efforts, to monitor undersea volcanoes, and guide autonomous vehicles underground and underwater. Muons are fast, subatomic-sized particles that have been used to wirelessly navigate underground.
MuPS was first created to help detect seafloor changes caused by underwater volcanoes or tectonic movement. It uses four muon-detecting reference stations above ground to provide coordinates for a muon-detecting receiver underground.
Early versions of muPS required the receiver to be connected to a ground station by a wire. However, new research uses high-precision quartz clocks to synchronize the ground stations with the receiver. The four parameters provided by the reference stations plus the synchronized clocks used to measure the muons’ “time-of-flight” enables the receiver’s coordinates to be determined. This system is called the muometric wireless navigation system (MuWNS).
To test the navigation ability of MuWNS, reference detectors were placed on the sixth floor of a building while a researcher took a receiver detector to the basement floor. They slowly walked up and down the corridors of the basement while holding the receiver. Rather than navigating in real time, measurements were taken and used to calculate their route and confirm the path they had taken.
The full published study can be found here.
