Japan is planning to develop an advanced sensor utilizing quantum magnetic technology for unmanned aerial vehicles (UAVs) capable of detecting submarines, according to a report by Nikkei Asia published today, September 10th. The new system aims to enhance Japan's underwater surveillance capabilities. This technology will allow UAVs to passively detect submarines by measuring subtle changes in the Earth’s magnetic field. Currently, submarine detection largely relies on sonar, which can be limited by noise and distance. The development of this quantum sensor could offer a significant advantage in identifying submarines without emitting signals. Japan's Ministry of Defense is reportedly investing in this research to bolster its defense posture in the region. The project seeks to counter growing submarine activity in waters surrounding Japan.