DARPA's Next Sub Hunter Won't Need Us Puny HumansS

The US Navy has a bit of a sub problem. While the American fleet has contracted over the past two decades, numerous nations that aren't exactly our BFFs have expanded, with new, ultra-quiet diesel-electric subs. This proliferation has grown into a national security threat, but DARPA may soon have a solution—robotic submarine trackers.

Sure, nuclear subs can remain underwater for months without refueling, but diesel-electric engines are no WWII relics, either. Especially not when they're enhanced with air-independent propulsion— technology that allows DE engines to operate without the need for a snorkel collecting atmospheric oxygen. What's more, they're nearly undetectable when running on battery power alone. So how does the US counter a double whammy of fewer sailors searching for more and better equipped enemies? By getting ACTUV.

The Anti-Submarine Warfare (ASW) Continuous Trail Unmanned Vessel (ACTUV) is a trimaran platform designed to operate completely autonomously for the duration of its operating cycle with zero human intervention. And without having to accommodate people, and all their housing and sustenance needs, the ACTUV can be built light and fast enough to outpace the diesel-electric subs it chases. It doesn't find the subs itself mind you, just tails them. "It relies on our hunters to hunt and find the submarine, but frees them from being tied down in asset-intensive continuous trail," said DARPA program manager Rob McHenry. In all, the ACTUV will be able to travel up to 3000km from its base, lurk around an area of ocean for up to a month, then pick up and trail a hostile sub over another 30 day stretch.

In order to do all this, the ACTUV will employ a combination of commercial off-the-shelf components supporting a suite of high fidelity sensors. The craft's C&C system will utilize advanced collision avoidance and navigation restraints to navigate the high seas without violating the Convention on the International Regulations for Preventing Collisions at Sea (COLREGS) and maritime law. The vessel's sonar is being built by Applied Physics Laboratory while Spatial Integrated Systems is developing the navigation algorithms.

"Key features and technology for the vessel include advanced software, robust autonomy for safe operations in accordance with maritime laws, and innovative sensors to continuously track the quietest of submarine targets," Scott Littlefield, DARPA program manager, said in a press statement.

"Our goal is to transition an operational game-changer to the Navy," he continued. "This should create an asymmetry to our advantage, negating a challenging submarine threat at one-tenth their cost of building subs. The program also establishes foundational technologies for future unmanned naval systems."

The ACTUV program has just completed Phase 1 with a successful proof of concept. Phases 2 - 4—to design, build, and test the vessel—should be completed by mid-2015. If successful, this platform could be a boon for the Navy, freeing up precious forces for other duties without letting hostile forces slip through their fingers. [Gizmag - DARPA - SpaceWar - Aviation Week - Image: DARPA]