The US Navy has a bit of a sub problem; while its fleet has shrunk over the past two decades, other countries that aren't exactly BFFs with the US have been expanding their own fleets of ultra-quiet diesel-electric subs. While this has grown into a very real national security threat, DARPA may soon have a solution in its robotic submarine trackers.
Sure, nuclear subs hold the advantage of never needing to be refuelled and the ability to remain underwater for months, but diesel-electric engines are no WWII relics, especially not when they're enhanced with air-independent propulsion technology that allows DE engines to operate without the need for a snorkel. 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 — it 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 command and control system will utilise 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 boom for the US Navy, freeing up precious forces for other duties without letting hostile forces slip through their fingers. [Gizmag - DARPA - SpaceWar - Aviation Week]