Technologies that for decades have been tested and deployed by the U.S. military are now being tailored for use by the Department of Homeland Security to protect the nation’s ports. Among them are radar, unmanned patrol boats, underwater sensors and nonlethal crowd-control weapons.
The detection of potential terrorists aboard small boats is one of DHS’ top priorities, said officials. This is a tough technical challenge because traditional maritime sensors are effective at finding large vessels but may not always see the fast-moving undersized boats that terrorists have used in suicide attacks, said Tim Gale, chief executive of Kelvin Hughes USA.
The company developed a “Sharp Eye” radar that was designed to detect small craft, he said. The system uses transistor-based “solid state” technology, which enables the device to send a more coherent wave and deliver an improved radar picture, Gale said.
“So what you put out is by comparison very clean, as opposed to being an indiscriminate bunch of energy that is just thrown out and bounces off of things,” Gale said.
Using the X-band frequency in sea state five — storm-like conditions with up to 16 millimeters of rainfall per hour — it can detect small craft six nautical miles away, Gale said. Traditional radars cover only three to four miles, he said. The S-band ranges up to seven miles.
“Say you detect a target moving 15 or 20 knots and coming straight for you … If you only detect it half a mile away, you don’t have a lot of time to react,” Gale said.
The Navy currently is evaluating this technology, Gale said.
Unmanned patrol boats also could help the Coast Guard expand its reach, according to General Dynamics, which has built two high-speed, 11-meter unmanned surface vessels for the Navy.
“They can come up and examine a small boat,” said Jack Flanagan, director of maritime systems at General Dynamics Robotic Systems.
The unmanned boat has a payload capacity of 5,000 pounds, can operate continuously for more than 24 hours and reach speeds of more than 35 knots. The firm is also developing a 7-meter craft.
The boats could be programmed to target vessels that are not equipped with the Automatic Identification System — a communication transponder that recognizes a vessel’s position, speed, destination and cargo. “If the craft [that it is observing] does not have an AIS system, it can check it out,” Flanagan said.
Underwater surveillance also is gaining acceptance as a key technology that can help detect explosives, although murky waters often prevent cameras from seeing smaller objects. A team of researchers at the Institute of Industrial Science at the University of Tokyo has developed a method to detect suspicious objects under ship hulls.
The researchers used a dual-frequency identification sonar acoustic camera — a device for underwater filming — to videotape under a ship. The team corrected the distortion and blurring that often occurs when the camera moves, said Akira Asada, researcher at the Institute of Industrial Science at the University of Tokyo.
A major challenge, however, lies not in collecting data but in making sense of it, said Kenneth McDaniel, maritime security deputy division chief at the U.S. Coast Guard office of counterterrorism and defense operations. “We could put a camera on the end of the pier, but at the end of the day somebody still has to look at what the camera is transmitting,” he said.
Other technologies seek to deter potential assailants. Raytheon’s Silent Guardian uses “active denial” technology to shoot a beam formed by millimeter waves. Unlike microwaves, these penetrate only the top 64th inch of human skin — just enough to cause pain but resulting in no bodily harm, said George Svitak, business development director for Raytheon’s directed energy products.
Beyond verbal warnings, military ships docked in harbors can do little to keep small boats away, and sailors fret that warning shots could accidentally hurt civilians, Svitak said. Silent Guardian can be used when a ship’s verbal warnings are ignored. Raytheon has delivered systems to the Air Force for tests and evaluations.