The US Department of Defense's technology research arm will be launching the largest unmanned surface vehicle ever built for hunting down trespassing submarines. The vehicle will be christened in April before it goes to the department for a demonstration.

The Defence Advanced Research Projects Agency (Darpa), the one credited with establishing the network that eventually transformed into today's internet, is in the final stages of production of the 130-feet long unmanned vessel in Portland, Oregon, under the Anti-Submarine Warfare (Asw) Continuous Trail Unmanned Vessel (Actuv) programme.

"Imagine an unmanned surface vessel following all the laws of the sea on its own and operating with manned surface and unmanned underwater vehicles," said Steve Walker, deputy director at Darpa, during a press meet at the Darpa headquarters in Virginia. "We think the real cost savings will be in operating this vessel at sea compared to how we operate vessels today."

According to Darpa, the primary goal of the project is to reduce the constraints on conventional naval submarine architecture. It aims to design and build a vessel that delivers higher propulsive performance, as compared to the diesel electric submarines, at a fraction of their size and cost.

The drone also employs non-conventional sensor technologies that can track the quietest submarine targets over their region. "While the Actuv program is focused on demonstrating the ASW tracking capability in this configuration, the core platform and autonomy technologies are broadly extendable to underpin a wide range of missions and configurations for future unmanned naval vessels," noted the programme description.

Darpa recently unveiled a drone under its Fast Lightweight Autonomy (FLA) programme. The drone can achieve target speeds of 20m per second. It also collaborated with Honeywell to build an augmented reality window for ground military vehicles.