China’s UV Crystal Aims to Enable GPS-Free Navigation for Submarines and Missiles
Chinese researchers say a fluorinated borate crystal can convert laser light to 145.2 nm ultraviolet, enabling extremely precise thorium-229–based nuclear clocks that could support GPS-free navigation for submarines, missiles, and spacecraft. If perfected, this could improve “dead reckoning” navigation and reduce reliance on GPS, though practical deployment remains uncertain and the technology is far from ready.