Sea wall: mesh of technologies to provide maritime safety net.

TAMPA, Fla. -- While the Department of Homeland Security begins efforts to strengthen the nation's land borders, less publicized work continues on building a so-called virtual wall along U.S. coasts.

As the defense communities and lawmakers debate what policies need to be implemented to protect ports, coastal waters and the seas approaching the United States, technological solutions are out there.

"If somebody could write me a check today, we could build it," Guy Thomas, Coast Guard maritime domain awareness program science and technology advisor said, referring to a system that would allow legitimate commerce through, while keeping bad guys out.

Once the Gordian Knot of interoperable communications and seamless information sharing is untied, the technological part of the problem is relatively easy, Thomas said at the Coast Guard's annual innovation conference and exhibition.

Coast Guard Commandant Adm. Thad Allen said the need to protect the nation's coasts should be a top priority. "Given the inherent vulnerabilities in the maritime transportation system and along our coastlines, I think what we need in this country is a maritime security regime that truly reflects the needs of a coastal nation state," he told reporters.

When and if Congress decides to write that check, there are a host of mature technologies ready to deploy.

"What you really want to do is identify a threat as far offshore as you can and defeat it the furthest distance from the port as you can," Allen said. And that begins with a layered defense. Because of the ocean's vastness, and the complications of sorting out legitimate seagoing traffic from lawbreakers or terrorist threats, no one solution will solve the problem, experts said.

Vendors and military researchers at the conference presented solutions ranging from the use of remote sensing satellites to peer thousands of miles out to sea, to cutting edge sensors designed to detect underwater saboteurs inside ports.

One system that has the green light and will begin operations in August is the vessel tracking project at the Coast Guard maritime intelligence fusion center-Atlantic in Dam Neck, Va.

The project will fuse multi-level intelligence data to help the Coast Guard and Navy track high interest vessels, according to Coast Guard Cmdr. John Wood, liaison to the Office of Naval Research.

The goal is to take information--everything from commercially available data to intelligence gathered by spy satellites--and provide a clear picture on one screen of what vessels are approaching U.S. shores.

Previously, intelligence personnel took several hours to gather all the data on a high-interest vessel, which required checking several databases and switching back and forth between computer screens, said Beth Gorko, signal solutions project manager at General Dynamics Networks Systems, a contractor for the project.

"It's really giving [analysts] much better information to work with," she said.

Easy to access data is generated by the automatic identification system (AIS), which transmits a vessel's identity, bearing and location. Other data fused into the system includes coastal radar and Navy acoustic signals. These are combined with "electronic surveillance measures," a catchall term for the intelligence communities' array of top secret sensors that can reach farther offshore.

Two experimental prototype buoys developed by the Naval Research Laboratory that employ hydrophones will also be deployed in the Atlantic near the Hampton Roads, Va., region, Wood said.

The vessel tracking project, however, is not connected to the maritime domain awareness community of interest--a joint effort by the DHS, the Coast Guard and the Navy to track vessels approaching U.S. waters. These agencies will begin a pilot project this fall to gather and send out information from AIS in a seamless manner.

The problem with relying too heavily on AIS data is that it can be manipulated, Wood said.

"The [fusion] system is designed to separate the unknown contacts from the known," he added. It will pick up ships that are not compliant with AIS or those that are "spoofing" the data, in other words, sending out false signals.

Anytime there is a disparity between what AIS tracking says, and what the sensors indicate, the system will automatically alert an analyst. A Navy or Coast Guard ship can then be dispatched to investigate, Wood said.

AIS transceivers are only as good as the information programmed into them, Wood noted.

Global positioning system units, for example, feed into the AIS system. Those can be manipulated to send out false signals. Ship names, registry numbers, and other data can also be changed.

"Ultimately, you need something AIS independent ... you have to augment that system with a camera or a sensor that validates that the information is correct," Wood said.

The project is funded by the Navy but administered by the Coast Guard.

The first phase of the project will cover the Atlantic, with the second phase beginning next year in the Pacific, Gorko said.

Other concepts for improving maritime domain awareness are still proposals, although they employ mature technologies.

One such concept uses the Navy's relocatable over-the-horizon radar (ROTHR) to scan millions of square miles of oceans. The radar bounces radio waves off the ionosphere, which reflects back targets to a separate reception facility, according to Bill Davis, of the ROTHR program.

ROTHR was a Navy Cold War era system designed to detect vessels and aircraft approaching from the Soviet Union. It was destined to be put in mothballs until it was transferred to the Pentagon's counterdrug surveillance and interdiction program in 1993.

Since then, it has been involved in dozens of drug interdictions, mostly by tracking small Cessna-sized aircraft in the Caribbean. There are three ROTHR sites in Virginia, Texas and Puerto Rico.

It cannot provide 100 percent coverage, since disturbances in the ionosphere can degrade its effectiveness, Davis noted.

OceanView, a space-based system proposed by Vexcel Corp. of Boulder, Colo., and the University of Miami's center for southeastern tropical remote sensing, analyzes wakes left by boats to determine bearings and speed.

It uses "readily available commercial satellite imagery," according to Hans Graber, the center's director.

The system was demonstrated for Coast Guard, Navy and DHS officials. It located and tracked vessels in a 4,600-square-kilometer swath in "near real-time" and provided reports formatted to NATO standards, including one-kilometer-by-one kilometer images of the targets.

Stephen Huett, director of airship programs at Naval Air Systems Command, and one of the military's leading proponents of lighter than air ships, said blimps and balloons can be a cost effective way to monitor the oceans. Sending a blimp to peer over the horizon is one-third the cost of flying fixed-wing or rotary aircraft, he said.

A misconception about their survivability is one of the obstacles to their use in the defense community. The belief that they are easily brought down by bullet holes is untrue, he said.

"They're very survivable," he said. Taking one down with bullets is like trying to "drain a swimming pool with a straw."

"They can be a cheap, persistent eye in the sky," he said.

Closer to shore, DRS Technologies, of Parsippany, N.J., is marketing a system to convert any boat into an unmanned surface vehicle.

At least a half-dozen companies are offering unmanned boats for military applications, including surveillance and reconnaissance and mine detection. The Navy has invested heavily in demonstration projects to prove their viability.

DRS' maritime security unmanned surface vehicle is a kit that can be mounted on any small boat. DRS mounted the system on an 18-foot boat at the conference.

A demonstration at Naval Station Pascagoula, Miss., for the Coast Guard showed the system's ability to interdict boats approaching a security zone in a simulated chemical plant accident.

"You wouldn't want to put a manned boat out to protect a restricted area warning people as a last line of defense, because the crew on the boat would have to be wearing chemical protective gear," said Shawn Black, director of business development for homeland security and unmanned systems at DRS' training and control systems based in Walton Beach, Fla.

The system's infrared camera also detected a Zodiac boat attempting to penetrate a security zone, and the USV forced the operators closer to shore where ground-based radar could pick them up.

The system has improved radio links and obstacle avoidance, which have been major challenges to unmanned surface vehicles. Hurdles include semi-submerged objects such as logs, pilings, buoys and other boats.

As a last line of defense, two Great Britain-based companies, QinetiQ Inc. of Farnborough, and Kongsberg Maritime of Aberdeen have developed swimmer detection sensors to prevent frogmen from launching underwater attacks. They can be used to protect ships or ports, said Larry Raithel, QinetiQ vice president for navy programs.

The Cerberus swimmer detection system sends out a high-resolution wideband active search sonar signal in 360-degree patterns at ranges of up to 900 meters. One unit can stand alone, or a series could be placed across a harbor to provide wider coverage. The software is designed to sort out human swimmers from marine animals.

As ports tighten security on the land entries, potential terrorists may look to the sea as a path of least resistance, Raithel said.

"The market is just now beginning to realize that you can tighten up security on the land side, but then your vulnerability becomes the sea side," he said.