Lightweight airborne sonar tracks multiple submarines
Leonardo's Ultra-LIght SonicS Enhanced System (ULISSES) sonar system recently completed a live sea trial off the coast of Italy. By processing signals from up to 64 sonobuoys and dipping sensors, it was able to accurately locate multiple, simulated submarines, opening the way for the system to go into production next year.
One of, if not the, major asset in anti-submarine warfare is sonar. Submarines are invisible once they submerge, which is why submariners divide the world into submarines and targets. However, the invention of sonar during World War I changed things. By being able to listen to the sounds made by submarines, the hunters soon became the hunted, sparking an arms race between stealth and sonar that continues to this day.
In the beginning, sonar was a listening device, which was then joined by an active system that sent out sonic pings that bounce off of underwater objects to reveal their existence. Over the decades, systems became more sophisticated as skilled human operators were aided and, in some cases, supplanted by increasingly complex electronics and computer algorithms that could not only detect sounds but also filter and analyze them.
What's unusual about ULISSES is that it's a lightweight package consisting of a processor, transmitter, receiver, and recorder weighing under 20 kg (44 lb) and is small enough to fit in a helicopter or a light unmanned aircraft, rather than in a ship or a large marine patrol aircraft.
Despite its small size, Leonardo says that it has a multistatic functionality that can collect and analyze data from 64 sonobuoys or dipping sonar sensors – even when they are deployed from other platforms. This allows it to not only identify multiple hostile submarines but also to triangulate their positions.
According to Leonardo, the recent sea trials were conducted in a realistic naval environment and the firm Ultra Electronics provided the sonobuoys – some of which were equipped with GPS capabilities. In the tests, ULISSES was able to identify targets and display them on an operator's workstation. The package can be retrofitted to existing aircraft, work with a wide variety of sensors for automatic tracking, and remotely control sonobuoys.