Bomb-Detection Technology Useful for Countermine Ops.

An explosive-detection technology developed for aviation safety could improve the ability of U.S. forces to locate and clear landmines, said Army and Navy scientists.

Unlike other areas of warfare, military countermine operations have not benefited significantly from advances in technology during the past several decades. Battlefield mine detection today essentially relies on metal-detector beachcombing devices that have been used since World War II.

To be sure, the U.S. Army is developing more advanced minesweeper vehicles equipped with ground-penetrating radar, infrared sensors, as well as the old metal detectors. But these systems suffer from high rates of false alarms and, because a lot of the work involves manually digging out mines or mine-like objects, the process is painfully slow.

The big breakthrough that has eluded scientists in the United States and elsewhere could come soon, as a result of research and development work funded by the Army, the Navy and the Defense Advanced Research Projects Agency (DARPA).

The technology that experts say could revolutionize mine detection is called quadrupole resonance, or QR It is a variation of the commonly used magnetic resonance imaging (MRI) technology, which physicians rely on to diagnose patients. It is also the same technology that scans baggage at airports and can detect explosives.

The MRI machines found at hospitals are large magnets, which affect the magnetic properties of the nuclei of the water in the human body. Those magnetic properties enable the machine to generate an image.

QR, however, does not use a magnet. The technology operates under the principle that a magnetic resonance signal can be detected from explosives without applying a large external magnetic field.

This is how QR works:

* A transmitter emits pulses of low-intensity radio waves.

* Nuclei within the explosive are momentarily aligned with the radio waves.

* After each pulse, the nuclei emit a characteristic radio signal, like an echo.

* The signal is picked up, amplified and analyzed.

* A computer issues a warning if it identifies a signal that is emitted only by explosives.

Pioneering developments in QR took place at the Naval Research Laboratory (NRL) in the early 1980s, explained Allen Garroway, a research physicist at the lab. "I was familiar with work that had been done in the United States in the 1970s on the use of QR for explosive detection," he said in a recent interview. That work was discontinued after the end of the Vietnam War.

But Federal Aviation Administration (FAA) officials came to NRL in 1983, looking for advice on how to use the QR technology for detecting explosives inside luggage. "I felt that the technique was worth looking at a second time," said Garroway. Since 1987, funding for QR work has come from the FAA and the Defense Department. In 1997, DARPA decided to support QR research for use in mine detection.

Some rudimentary work had been done on this technology by the former Soviet Union, said Garroway. But after the end of the war against Afghanistan in the early 1980s, the Soviets dropped those efforts.

NRL patented the technology at various times. In 1993, the lab gave an exclusive license to Quantum Magnetics, a San Diego-based company. Since 1997, the company has received $38 million in contracts from DARPA and the Office of Naval Research to develop mine-detector prototype systems for the Army and the Marine Corps.

The "beauty" of QR, explained Garroway, is that it is highly sensitive to the chemistry of explosives. If a bag containing explosives is scanned using QR, the machine flashes a red light. And, so far, tests have shown that the technology accurately detects the presence of explosives, without false alarms.

It is estimated that, in mine-clearance operations, for every real mine, there are between 100 and 1,000 false alarms.

The problem with virtually all the existing technologies used to find hidden explosives, such as X-ray or radar, is that they pick up too many ancillary objects, said Garroway. "A landmine may give a signal, but a rock or a piece of metal also may give a signal." QR sensors pick up the so-called resonance frequency, which is quite specific for different explosives. Combat mines typically contain the explosives RDX, TNT and Tetryl. "If you can detect those three explosives, you can detect most of the others," said Garroway.

And, unlike electromagnetic systems, QR sensors can detect plastic-encased mines. About 60 percent of anti-personnel landmines and 75 percent of antitank mines buried around the world are metal-cased.

"The most difficult mines to detect are the small plastic-cased mines, which only have a small fragment of metal," said Lowell Burnett, chief executive officer and president of Quantum Magnetics. "It's very difficult to distinguish these plastic-cased mines from shell fragments, cartridge casings and other metallic debris scattered around the battlefield."

But despite promising developments in QR, the technology is not nearly mature enough, Garroway said. "There is still a lot of work to be done. It's a tough problem... We would consider ourselves very successful if there was a system out in three to five years.

Garroway does not expect that QR technology will be any more expensive than ground-penetrating radar, but it will be costlier than the conventional electromagnetic metal detectors.

Electromagnetic systems not only have a high rate of false alarms, but also are manpower-Intensive, which makes them dangerous, he said. "The current method is to dig up the mine, inches away from your hand and a foot away from your face."

Vehicle Systems

The mine-detection prototypes currently in development by Quantum Magnetics include a vehicle-mounted system for the Army, and a backpack-size device for the Marine Corps.

For countermine operations, the Army currently relies on the so-called Interim Vehicle-Mounted Mine Detector (IVMMD), which was developed in South Africa. The four-wheeled IVMMD, which looks like a road grader, was designed to detect metal-cased antitank mines on roads. A complete system includes three platforms: a mine detection vehicle, a towing vehicle and mine detonation trailers.

The Army has 10 IVMMD systems. One is at the Army's engineering school in Fort Leonard Wood, Mo. The other nine are stored in a California depot. These systems are used only for military operations, not for humanitarian demining.

To replace the interim vehicle, the Army is developing the Ground Standoff Minefield Detection System (GSTAMIDS). Block 0 is the first iteration, explained Brian Green, project management engineer at the Army's program office for mines, countermines and demolitions.

Block 0 has a multi-sensor array with metal detection, ground-penetrating radar and infrared capabilities. The goal is to clear 20 km of road in 12 hours.

The QR sensors will not be part of GSTAMIDS until the Block I upgrade, Green said in an interview. Block 0 development should be complete by fiscal 2002 and could go into production by fiscal 2003.

Block I work will begin this year, and the development phase is expected to last 36 months.

The benefit that QR brings to the GSTAMIDS is that it can confirm or deny the presence of explosives without having to dig up every suspect object, explained Vivian George, Army project engineer.

Ground-penetrating radar (GPR) has a lot of false alarms, but that is the only technology available today to detect plastic-enclosed mines, she said. "We have been looking at GPR since 1945, and nobody has been able to make it work very well."

The QR system would confirm or deny the presence of explosives after the radar has detected a potential mine.

Finding buried explosives is a much harder problem that scanning baggage that contains a hidden bomb, Green said. "It's much easier to put a suitcase into a scanner than it is to move something down the road and have to look underground and look for smaller targets that are cased in plastic and metal."

According to George, "It's much easier to create a uniform magnetic field inside a tube, like the luggage scanner. When explosives are underground, you can't run them through the tube. You have to design a coil that can project the magnetic field into the soil" and receive signals from underground.

The concept for the GSTAMIDS Block I is to have the mine-detection vehicle upfront and a separate QR-equipped vehicle following behind. The lead vehicle puts a splat on the ground, indicating there's a potential mine. The trailing QR vehicle has a transmitter that sends signals or pulses down to a detection coil, made of copper. The coil analyzes the slat and the system produces a red light if explosives are found.

"If there are explosives, that is considered a mine threat, even if it's ordnance," said George. "If there is no mine threat, then you don't waste time digging, as you would with the Block 0 system.

Unlike the IVMMD, the GSTAMIDS vehicle has a hydraulic arm, resembling a crane, to dig up mines remotely, from inside the vehicle. But unlike the Block 0 version, the QR-equipped Block I system saves operators time because they only will dig up objects that contain explosives, she said.

The Block 0 system requires a crew of five. That is an improvement over current operations, which require a company of engineers, who proceed at a speed of less than 1/2 km an hour. That means it would rake them days to clear a 40 km area. With the Block I system, said George, the goal is to move at 7 km per hour and clear the 40 km route in six hours.

George said her office has received many requests from other nations to share the QR technology for mine detection. The French, Germans, Canadians and English are "dabbling with QR," she said. "What I have told them is to wait, and let the United States spend the money, do the research and the engineering. If it works, I am sure we can find a way to do technology transfer."

There also could be potential technology spin-offs for humanitarian demining, which involves removal of anti-personnel mines that were laid in many Third World countries--during civil wars, for example. "Humanitarian demining is more challenging because anti-personnel mines have a small amount of explosives," said George. Those small mines, however, maim and kill thousands of civilians each year.

"If the [Navy's] QR backpack system works, that has more potential for humanitarian demining," said Green.

The Army would have an interest in the backpack system that is in development for the Marine Corps, said Green. "But that is significantly more challenging than what we are trying to do."

Burnett, the president of Quantum Magnetics, said that QR mine detectors were tested successfully in March 1999, at Camp Pendleton, Calif., in Bosnia, in July 1999, and at Fort Leonard Wood, in October and December 1999.

He agreed that the backpack system will be "difficult" to achieve, because of the size requirements. It will have a wand-like detector to sweep the ground. The backpack holds the electronics and the battery power. As the coil moves over the ground, it flashes red or green lights, depending on whether there are explosives underground.

The backpack system has the same technology as the vehicle prototype. But squeezing all the electronics into a man-portable system is a huge "engineering challenge," Burnett said. "Our goal for the backpack is to get the weight down to less than 35 pounds." By comparison, "the system we took to Bosnia weighed more than 500 pounds."

Garroway, the Navy scientist, said he is "optimistic" that QR will become a mainstream technology. But he cautioned that no single technique by itself is going to be a complete solution. "I anticipate that QR will be combined with other techniques, he said. "All these techniques will be complementary in some sort of integrated package."

One important consideration is the confidence that any system offers the soldiers, said George. Today's systems, she said, fail to do that.

"If you have a system that soldiers are confident in, they are confident in using the route after it's been cleared. Now, they don't trust the system."