Японские ученые испытали навигационную систему на основе космических частиц для работы под землей и под водой

GPS has become essential for navigation. But there is one major limitation: GPS signals cannot travel through water, rocks or deep underground spaces. To address the problem, scientists in Japan are now testing an alternative navigation system that uses particles from cosmic rays instead of satellites. According to a report by Ars Technica, the system is called the Muometric Wireless Navigation System, or MuWNS. It uses naturally occurring particles known as muons to determine location in places where GPS cannot work, including underground, indoors and underwater. The researchers say the technology could one day help guide robots during search and rescue operations, support autonomous vehicles in underground spaces and improve navigation in places where satellite signals are unavailable. How cosmic rays could help navigation work underground and underwater Cosmic rays constantly produce particles called muons that fall across the Earth. Unlike GPS radio signals, muons can pass through dense materials, including water and large amounts of rock. “Cosmic ray muons fall evenly across the Earth and always travel at the same speed no matter what material they pass through, penetrating even kilometers of rock,” Hiroyuki Tanaka of the University of Tokyo said. “Now, using muons, we’ve developed a new type of GPS, which we’ve called muPS, that works underground, indoors, and underwater.” The technology works by using reference stations placed above ground along with a receiver that detects muons below the surface. By measuring the particles and using synchronized clocks, the system can calculate the location of the receiver. Muon technology is not entirely new. Scientists have previously used muons to study volcanoes, examine ancient structures and search for hidden spaces inside pyramids. The Japanese researchers are now exploring whether the same particles can help solve a different problem: navigation without satellite signals. Scientists tested the system by walking through a building basement Earlier versions of the system required the receiver to be connected to a ground station with wires, limiting where it could be used. The new MuWNS system is wireless and uses accurate quartz clocks to synchronize the reference stations and receiver. For a test, researchers placed reference stations on the sixth floor of a building while a person carrying the receiver walked through corridors in the basement. The system tracked the person's route and was able to reconstruct the path taken. The researchers reported an accuracy of between 2 and 25 metres, with a range of up to 100 metres. “This is as good as, if not better than, single-point GPS positioning over the ground in urban areas,” Tanaka said. However, he added that the technology is still far from being ready for everyday use. “People need an accuracy of one meter, and the key to that is time synchronization.”