Japan is planning to develop quantum magnetic sensors that can be fitted to drones to detect submarines, as it looks for new ways to strengthen its maritime surveillance.The plan is part of Tokyo’s wider push to bring advanced technologies into its defence systems and improve its ability to monitor waters around the country.The sensors would be designed to pick up very small changes in magnetic fields caused by submarines.By putting them on unmanned aircraft, Japan could monitor larger areas without having to depend entirely on crewed aircraft or other expensive surveillance platforms. The technology could eventually give the country another tool for tracking underwater activity.Key Highlights Japan plans drone-based quantum sensors to detect submarines and underwater threats Quantum magnetometers could strengthen Japan’s maritime surveillance capabilities Japan explores drones and quantum technology for advanced submarine detectionQuantum Sensors Improve Submarine DetectionThe proposed system would use quantum magnetometers, which are highly sensitive instruments capable of detecting small changes in magnetic fields. In military applications, these sensors can support magnetic anomaly detection, a method that looks for changes in Earth's magnetic field caused by large metal objects such as submarines.Using drones for submarine detection could give Japan more flexibility. Unmanned aircraft can be deployed without putting pilots at risk and could potentially stay in the air for longer periods. They could also be used to search wider areas, depending on their range and operating capabilities.Japan's plans are part of a wider global interest in quantum technology for defence. Countries such as the United States are also looking at quantum sensors for uses including submarine detection, navigation and other forms of surveillance.There are still challenges to overcome. A quantum sensor does not automatically make a submarine easy to find. Detection can depend on the distance between the sensor and submarine, the size and magnetic signature of the vessel, and interference from the surrounding environment.Japan will therefore need to make the technology small and light enough for drones while ensuring that it can work reliably in real-world conditions. The sensors will also have to cope with vibration, weather and other conditions encountered during flight.Japan Expands Unmanned Defence CapabilitiesThe project comes as Japan increases its focus on drones, artificial intelligence and other unmanned technologies. Tokyo is looking at these systems as a way to strengthen surveillance while reducing the risks and costs associated with some traditional military platforms.Japan's interest in submarine detection technology is also linked to the changing security environment in the region. China's growing naval capabilities and expanding submarine fleet have increased the importance of monitoring underwater activity in waters around Japan.The country is also exploring ways to connect different unmanned systems. Recent trials involving underwater vehicles and unmanned aircraft have demonstrated how aerial platforms could support operations below the surface by collecting or transferring information.If the quantum-sensor project succeeds, drones equipped with the technology could eventually become part of a larger network of maritime surveillance systems covering air, surface and underwater operations. This could help Japan monitor larger areas and respond more quickly to possible underwater threats.Also Read: Japan Expands Unmanned Defence CapabilitiesFor now, the technology remains under development, and it is too early to say when it could become part of Japan's operational defence capabilities. However, the project highlights Tokyo's growing interest in combining drones with emerging technologies to improve its ability to detect and monitor underwater activity.