Japan eyes quantum sub-hunting drone sensors as China extends undersea reach

Japan’s fiscal 2027 defence budget request includes research on a smaller quantum magnetic sensor for detecting submarines from uncrewed aircraft. The device would measure minute variations in magnetic fields that may reveal a submerged hull, with development targeted by fiscal 2031. Tokyo envisages low-cost drones flying near the sea surface and operating from warships, potentially widening anti-submarine coverage while reducing crew and aircraft demands. Funding is not yet final, and sensor sensitivity, environmental noise, flight endurance and integration must be proven before the concept can become an operational detection system.