One of the biggest threats to U.S. naval vessels comes in a small package — a motorboat or other small watercraft, packed with explosives and manned by individuals ready for a suicide mission. This is how the USS Cole was struck in October 2000 while it was berthed in the Yemeni port of Aden, killing 17 American sailors and injuring another 39.
Now the U.S. Navy has an answer to that threat: autonomous swarm boat technology, which turns small patrol craft into unmanned autonomous surface vehicles (USVs) that can communicate and coordinate among themselves.
Using software NASA developed for its Mars rovers as a starting point, the Office of Naval Research created a customized system that can be installed on any small patrol boat, converting it into a fully unmanned operational craft.
Called the Control Architecture for Robotic Agent Command and Sensing (CARACaS), the technology incorporates a fast-route planner for collision avoidance that ONR developed to supplement NASA’s software since the Mars rovers do not move quickly and didn’t require that kind of tool, Robert Brizzolara, the program manager at ONR, said.
The system “fuses situational awareness data across multiple USVs and provides each boat with a common picture,” Brizzolara said. It also directs each vessel to follow autonomous “behaviors,” such as “escort” and “attack,” that meet various maritime missions.
Navy officials demonstrated the technology in August on the James River near Norfolk, Va., where they used CARACaS-equipped patrol boats to protect a designated vessel from a threat.
“[T]ens, 20s, 30s of these vessels … can now work collectively together in swarming, protecting a high-value asset,” Rear Adm. Matthew Klunder, chief of naval research, said.
“A patrol craft usually mans with three or four sailors each,” he said. By using unmanned craft, working together, “all those sailors can be back [on board], running a weapons system, doing something we desperately need them to do, and out of harm’s way.”
The swarm can provide a buffer zone around any designated “high-value asset,” as Klunder described them — anything from Navy vessels to cargo ships, offshore platforms to ports and harbors.
A human operator, who can be on the protected vessel or elsewhere, tells the swarm which vessel to guard and which might be a threat. Beyond that, the swarm can coordinate their positions relative to the target and the threat, run interference, surround the threat and even attack it with non-lethal or lethal weapons. Non-lethal weapons include bright lights, sounds and high-powered microwaves, Brizzolara said.
ONR has also developed “a longer-range, higher frame-rate stereocamera than what was on the Mars rover,” Brizzolara said. “The stereocamera provides near real-time imagery of objects in the water that the USV has to avoid, as well as the distance to that object” to guide boats more precisely at high speed.
When asked if there are weather limitations, such as high seas or heavy fog, Brizzolara said ONR is developing additional technologies that would allow CARACaS to operate under those conditions.
“They should be available for initial testing soon,” he said.