'Brain-Based Controller'

Sea Power, Jul 2005 by Hamilton, Robert A

It is one of several concepts that will lead to a vastly expanded array of missions for the Navy's growing fleet of underwater vehicles

Explorations

The Pentagon is pushing technology improvements to get more out of its unmanned underwater vehicles (UUVs).

* DARPA is looking for ways to send UUVs on missions lasting longer than 30 days.

* One possibility: an unmanned mother sub to take swarms of small attack subs closer to targets.

* New materials and fuel cells are keys to the future.

One of many elements in the Navy's new master plan for unmanned underwater vehicles (UUVs) is a concept for a large mini-sub - 10 tons or more - that could be launched from the new class of SSGN cruise-missile submarines or the planned Littoral Combat Ship and carry dozens of smaller UUVs closer to a target.

For example, an SSGN would dispatch a mother-mini into the middle of a minefield that has been mapped by a specialized unmanned vehicle. The mother sub would deploy smaller UUVs to neutralize each mine on the map.

The Navy also envisions underwater vehicles of the future capable of missions lasting longer than 30 days, and the development of a "brain-based controller," which would be based on the motor control system in animal brains, enabling unmanned subs to deal with vagaries of the underwater environment such as turbulence or obstacles in their paths.

The new UUV master plan, a roadmap to the future for one of the Navy's more intriguing and fast-growing classes of weapons, also calls for an array of portable devices weighing 25 to 100 pounds with an endurance of 10-20 hours and a payload of one-quarter of a cubic foot. A lightweight class of UUVs, 500 pounds and 12.75 inches in diameter, would have double the endurance and six to 12 times the payload of a portable UUV Heavyweights would weigh up to 3,000 pounds and have a diameter of 21 inches, enabling them to be launched from the torpedo tube of an attack submarine.

Approved by senior Navy officials in November 2004, the new master plan also proposes nine high-priority missions for UUVs, ranging from intelligence, surveillance and reconnaissance, and mine countermeasures to communications and time-critical strike.

The range of missions is indicative of the growing sophistication of sensors and other UUV technologies. The service's first roadmap for UUVs, completed in 1994, consigned underwater vehicles largely to mine countermeasures work. But the service today has some ambitious goals for what are becoming increasingly known as AUVs, or Autonomous Underwater Vehicles.

This smarter, more sophisticated class of underwater vehicles is expected to bring substantial added value to the Navy. "What we're talking about here is operational, seagoing, warfighting capability," said Capt. Paul D. Ims, who heads the AUV office at Naval Sea Systems Command.

Owen R. Cote Jr., associate director of the Massachusetts Institute of Technology (MIT) securities studies program, said he still views UUVs as underwater trucks, good at tasks such as deploying or maintaining underwater communications or sensor grids.

"It doesn't seem possible to solve some of the undersea challenges we face in the future unless we can move things on and off submarines very easily, and AUVs will play a big role in that. But we still don't know what we're going to be moving, so it's difficult to say what we will need in an AUV," Cote said.

There are still significant technical challenges to be overcome, particularly in the areas of energy storage, communications and autonomous control, but the Navy and its partners have efforts under way to address those shortcomings.

The Defense Advanced Research Projects Agency (DARPA), for instance, recently hosted a "UUV Power Systems Workshop" that drew 160 representatives from 80 different corporate, government and academic institutions. DARPA said it is seeking ideas on everything from advanced thermal engines that might be small enough for UUVs, to structural or hull elements that could double as energy storage materials - anything that will extend the reach of a UUV.

"DARPA is interested in air-independent (i.e., no snorkeling), innovative technologies that can enable long-duration UUV missions," said spokeswoman Jan Walker in a written response to a query. "There are no 'preferred' technologies at this time."

By long duration, she said, DARPA is looking at missions greater than 30 days.

Fuel cells hold perhaps the most promise for UUV technology, because they would allow onboard generation of power, said Chryssostomos Chryssostomidis, head of the MIT's AUV lab. Fuel cells would give UUVs endurance, and they are small, uncomplicated and quiet.

The MIT lab is also working on the problem of communications. Chryssostomidis said breakthroughs coming in this area could soon enable data transfer rates of 150 kilobytes per second from a submerged UUV, about three times what the Navy says it needs for UUVs doing mine countermeasure work.

"We are experimenting right now with new signal processing techniques that allow us to go into much higher rates," Chryssostomidis said. "We have already demonstrated that, in ideal situations, we can do that."