A prototype device called the RADAR Flashlight, developed at the Georgia Tech Research Institute (GTRI), can detect a human's presence through doors and walls up to 8 inches thick.

The device uses a narrow 16-degree radar beam and specialized signal processor to discern respiration and/or movement up to three meters behind a wall. The device can penetrate even heavy clothing to detect respiration and movements of as little as a few millimeters.

"We believe the RADAR Flashlight potentially will be useful to police officers in ambush situations," says Gene Greneker, the GTRI principal research scientist who led the development of the device. ".... It is a force multiplier and a safety enhancement tool."

The RADAR Flashlight is undergoing further modification and testing for the next six months. The Georgia Institute of Technology has filed a provisional patent for the device, which could become commercially available to law enforcement officials within a couple of years if the university licenses the technology to a manufacturer.

With funding in 1998 from the National Institute of Justice (NIJ), a division of the U.S. Justice Department, Greneker and his team took the RADAR Flashlight from a bulky three-part prototype to a self-contained unit that weighs about 7 pounds. The NIJ tested the device last year at the National Law Enforcement Corrections Technology Center in Charleston, S.C., and suggested further modifications. Work on those changes is expected to begin this spring with additional funding from the NIJ.

"We will be modifying the RADAR Flashlight based on what law enforcement officials told us from the tests," Greneker says. "For one thing, they said it makes too much noise when it locks onto a wall (to scan). Also, for use by SWAT teams, the RADAR Flashlight needs to be operated by remote control. So we plan to put the RADAR Flashlight on a tripod at least 25 feet away from a wall and steer it by remote control to the part of the wall we're interested in scanning."

When these modifications are complete, the RADAR Flashlight will undergo more rigorous testing in various environmental conditions.

In its current form, the RADAR Flashlight operates in the following manner:

The user holds the device with a pistol-grip handle, pulls a trigger, and the device runs a 3-second self-test to verify that it is properly functioning. The user sees the results as a bar graph on a small LED display built into the device.

Then the user presses the device against a wall, pulls the trigger, and within 3 seconds the system automatically spaces itself from the wall at a distance designed for best performance.

The RADAR Flashlight's narrow radar beam sends out a pulse of electromagnetic energy, then detects the return signal, which is read by high-speed signal processing technology that quickly delivers bar-graph results to the user's display.

As the person on the other side of the wall breathes, the bar-graph display rises and falls with a rhythmic response.

Research that evolved into the RADAR Flashlight began at GTRI in the mid-1980s with the patenting of a frequency-modulated radar for remotely checking vital signs of soldiers wounded on the battlefield before risking medics' lives to save the injured.

This early technology also was tested for its ability to monitor vital signs of soldiers clothed in chemical or biological warfare suits, without requiring them to risk contamination by removing the protective gear.

Today, a technical challenge remains for researchers working on the RADAR Flashlight.

"We have one problem," Greneker says. "This instrument is so sensitive to motion that if you don't hold it still enough, it will detect its own self-motion. If we can overcome this, it would be the Holy Grail, and interestingly enough, we think we know how to solve this problem with additional research."

Bill Deck of the National Law Enforcement Corrections Technology Center cited the RADAR Flashlight's stability and LED display as key issues to target before the device is commercialized.

"The RADAR Flashlight has some potential," Deck said. "There is some interest from police departments. They gave us about 25 scenarios in which the device could be useful. For example, when an officer goes to serve a warrant, it could let him know that someone is standing behind the door, maybe waiting to ambush him."

Greneker says he is encouraged by interest from police departments and hopes the RADAR Flashlight will be commercialized soon.

"Our target sales price is $1,000 to $1,500 per device," Greneker says. "That price range is important to police departments because they usually don't have a lot of money to spend."

Meanwhile, other companies have developed a micro-impulse type of radar intended for the same purposes as the RADAR Flashlight. The micro-impulse radar spreads energy over a broad band of frequencies using a technique not yet approved by the Federal Communications Commission, Greneker says.

The RADAR Flashlight operates on a narrow frequency in a license-free band, he adds. It can detect motion and/or respiration through brick, wood, plasterboard, glass and concrete. It will not work in water or on metal structures, such as mobile homes, because these materials are electrical conductors.

For those concerned about radiation exposure from the flashlight, Greneker says the emission is very small -- meeting national standards for the maximum human exposure limits. It emits about the same amount of radiation as a person receives when standing in front of a microwave-actuated door in a store. - By Jane M. Sanders

[Contact: Gene Greneker, Bill Deck, Jane M. Sanders]

16-Apr-2001