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Tunnel vision

U.S. intel community seeks new ways to peer into underground sites

Aug. 1, 2009 - 03:45AM   |  
By Keith Button   |   Comments
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Mitchell Catanzaro figures that early in his career, he lived six months underground in Grand Forks, N.D., tending to Minuteman ICBMs in their hardened, 80-foot-deep silos, designed to be virtually immune from nuclear attack.

Now, Catanzaro spends his time thinking about ways to find and destroy the other guy's increasingly numerous underground sites, tunnels and bunkers that could house clandestine weapons programs or shield the leaders of rogue states. Catanzaro is an intelligence officer at the Underground Facility Analysis Center, a consortium of intelligence experts and engineers from the Defense Intelligence Agency, the National Geospatial Intelligence Agency, the Defense Threat Reduction Agency and the National Security Agency. When then-Director of Central Intelligence John Deutch established the center in 1997, it had 20 people. Now, it has a staff of 240 operating from a commercial building in the Virginia suburbs.

The U.S.' ability to look deep inside the borders of other countries by orbiting satellites over them or by peering in from international airspace has prompted more potential enemies to hide secrets underground. So, the U.S. has been stepping up its efforts to spy on underground facilities and develop technologies specifically for subterranean ISR.

Some U.S. intelligence managers are concerned that those efforts are not enough, and they have taken the unusual step of encouraging one of their own Catanzaro to speak and write publicly about the challenges posed by underground bunkers and tunnels. Intelligence officials report there are thousands of these around the world potentially hiding or safeguarding weapons of mass destruction, or weapons development efforts.

It is an exponentially growing threat, Catanzaro said. "If we are going to successfully combat the growing use of underground facilities by potential adversaries, we are going to have to dedicate the resources, i.e., personnel and dollars, to do it," he said by e-mail through his public affairs staff.

"It's not a sexy issue. It's not a front-page news story," Catanzaro said. "It won't be until something makes the public think: ‘What happened? This is the United States. Why can't we do XYZ that the president wanted to do?' "

Assigning more personnel to the problem will not be the sole answer, he said. Better sensors and analytic tools are needed, and they might reduce the number of personnel that would be required otherwise. "For instance, if we had a sensor that could see through the earth, you would need a lot less effort, i.e., analysts, dedicated to detecting underground facilities," he said by e-mail. A weapon capable of penetrating "hundreds of meters of hard rock" also would help, Catanzaro said.

Catanzano sees three main reasons for the proliferation of underground facilities.

One is the above-ground reconnaissance abilities of the U.S. Second, foreign countries know that in NATO's 1999 Kosovo war, U.S. bombs could not destroy Serbian facilities located deep underground. The third reason is an advance in tunnel-building technologies over the last 20 years that has made them cheaper to build.

While the Soviet Union was known to have extravagant underground operations during the Cold War, Catanzaro said, they were very expensive to build. Today, with advancements in tunnel-boring machines and related underground construction technology for subways, dams and other nonmilitary projects, it is relatively easy and inexpensive to build underground facilities or tunnels to hide more nefarious military or terrorist activities.

That means that geologists, engineers and oil and mineral exploration experts have been enlisted in the U.S. effort against underground facilities, along with the more typical intelligence sources and technology, Catanzaro said.

The U.S. Defense Advanced Research Projects Agency (DARPA) has led some of the research toward countering underground facilities. Intelligence officials are anxious to see how the agency's incoming director, Regina Dugan, a former DARPA researcher and cofounder of the anti-explosives company RedXDefense, will treat the work.

DARPA has funded one program meant to help troops or intelligence agents navigate through tunnels once they are discovered. The goal would be to provide troops with lightweight GPS-style devices that could be carried while operating in a vast underground enemy tunnel or cave system.

One approach, called sferic-based underground GPS (S-BUG) would triangulate the radio signals produced by the lightning strikes for navigation, even when those strikes are thousands of miles away. Sferic refers to the electro-magnetic radio waves that emanate from lightning.

An alternative technique called subsurface navigation (SSN) would use magnetic signals transmitted from beacons on the earth's surface, most likely air-dropped into the field of battle or carried in and placed by troops. Those underground, meanwhile, would carry a magnetometer as a receiver, honing in on the beacons' signals.

Both approaches would use the basic principal of calculating position by receiving signals from sources with known positions, said Stephanie Tompkins, DARPA program manager for S-BUG and SSN.

The physics are very different when the signals have to reach underground, Tompkins said. "Propagating through the earth is a tremendous challenge," she said.

S-BUG would take advantage of low-frequency radio signals that travel for thousands of miles across Earth's surface and also penetrate the ground. Those signals could be used to pinpoint the location of an underground navigator if that navigator knew the location of the lightning strike. Lightning location information would be provided by receivers on the earth's surface perhaps hundreds of kilometers from underground troops, Tompkins said. Those receivers would calculate the lightning location with the help of extremely precise clocks. Those underground would be equipped to receive both the lightning signals and location information from the above-ground receivers.

Ideally, Tompkins said, if S-BUG were determined to be feasible and the Pentagon developed a version for the field, troops would need only an antenna and a software plug-in for the GPS or radio device they already wear.

The SSN system also would have challenges, one being the need to filter out the naturally occurring magnetic signals that might interfere with the receiver's readings. "If you carry around a magnetic compass and it gets too close to a car, it's not necessarily pointing north," Tompkins said.

Another challenge would be making the beacons small and efficient enough that they would not require too much battery power, yet have a strong enough signal that they could be modulated, Tompkins said.

DARPA started the first stage of S-BUG development in March to determine whether the idea is worth exploring further. DARPA awarded $1 million in contracts to Argon ST and SRI as the lead contractors but would not identify the funding split.

SSN is further along in development. A proof-of-concept version is scheduled for field tests meant to show the military services that such a system could be developed, and what depth and range it might have, Tompkins said. Then it would be up to the potential end-users to decide whether to take the reins, potentially starting their own research and development efforts. The lead contractor for SSN is Raytheon's UTD subsidiary, formerly a small company known as UTD Inc., which Raytheon purchased in 2005. DARPA has awarded about $7.5 million worth of contracts so far for SSN.

The list of ideas for improving surveillance of underground sites and attacking them when necessary is long.

Under DARPA's Airborne Tomography using Active Electromagnetics program, engineers are trying to develop a system to detect and map out tunnels and other underground structures by illuminating them with electromagnetic energy beamed down from an aircraft. BAE Systems Electronics and Integrated Solutions Inc. of Washington, D.C., is the prime contractor on that program.

Earlier this year, Raytheon won a $19 million contract from DARPA to develop a seismic and acoustic vibration imaging system. It would generate ground vibrations to produce images of tunnels and land mines near the earth's surface.

DARPA also has hired Sandia National Laboratories for the initial phase of a Strategically Hardened Facility Defeat program to develop technologies to enable non-nuclear weapons to penetrate deeply buried targets.

DARPA has also asked potential contractors for proposals to build a prototype airborne system that would detect variations in the earth's gravity field to locate and characterize tunnels. Proposals for the Gravity Anomaly for Tunnel Exposure (GATE) program were due in June.

About a year ago, DARPA wrapped up an effort to detect the presence of tunnels indirectly with a device called a Low Altitude Airborne Sensor System (LAASS) that would fly on a UAV. A LAASS would use magnetometers to detect underground power lines and acoustic sensors to detect noise from vents. BBN Sensor Systems of Cambridge, Mass., was awarded a $3.13 million contract for LAASS.

During tests in Arizona, a UAV flying at very low altitudes carried magnetometers for locating power lines and energized wiring within underground facilities, and energized power line spurs not connected to above-ground buildings, said George Shepard, lead scientist for BBN. The same UAV also carried microphones for picking up on fans or other noises coming from vents. BBN tried mounting the LAASS on a helicopter, but engineers could not insulate it well enough from the helicopter's vibrations.

One goal of the system would be to map an underground facility based on its wiring layout. While the project met nine of its 10 go/ no-go goals, one goal related to a mapping function was not met. DARPA decided not to take the project to the next phase, in which engineers would have built a working prototype to demonstrate against real targets, Shepard said.

"Personally, I think we met the metrics, and we were disappointed it didn't go to Phase 3," Shepard said.

Ultimately, the challenge of locating and penetrating underground facilities may come down to whether the U.S. can develop "exquisite intelligence," said Catanzaro of the Defense Underground Facility Analysis Center

Instead of trying to develop a non-nuclear weapon to penetrate a hardened bunker buried hundreds of meters underground, which may be impossible, the U.S. might be able to develop tools and techniques for finding and collapsing its key portals, for example, Catanzaro said. Or, an underground facility may be rendered useless, even if the structure remains intact, by cutting off its power or taking out its command and control functions.

"There's no silver bullet for finding and characterizing underground threats," he said. "We need new tools in the tool box. We have to invest in tools and techniques."

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