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ALBUQUERQUE, N.M. — A recent Sandia National Laboratories’ double-blind test of an instrument that its manufacturer said could detect the presence of human beings at a distance through any material found no evidence that it could do so.
The test results showed that the DKL LifeGuard Model 2 “human presence detector” failed to meet its published specifications and its performance was no better than random chance.
The Department of Energy’s (DOE) Office of Safeguards and Security asked Sandia to evaluate the performance of the DKL LifeGuard, from DielectroKinetic Laboratories, LLC. The company advertised that some models of the device could detect living human beings at distances of up to 500 meters through any material. (The model tested has a published range of 20 meters.)
Such a capability, if demonstrated, could be a tremendous help in search and rescue, law enforcement, and security operations. Word about the device had gained attention in government circles. Its list price ranges from $6,000 to $15,000, depending on the model.
The question posed to Sandia was simply: “Does this device work?”
Sandian technical staff members Dale Murray, Debra Spencer, and Floyd Spencer designed a double-blind test to determine whether the device would perform as advertised. Murray and Debra Spencer are in Sandia’s Security Systems & Technology Center, and Floyd Spencer is in the Surety Assessment Center.
Related to DOE responsibilities
Murray says the DOE request was related to his responsibilities as project leader for Sandia’s and DOE’s entry-control project. “We work in the area of access control, and other departments in our center deal with intrusion-detection sensors,” he said.
The device tested consists essentially of a black rectangular box about 3 inches tall, 1 inch thick, and 8 inches long. When a handle that comes out the box is used, the box swings freely. There’s also an antenna, a small laser similar to those in lecture pointers, and a red LED light. There are some electronics inside.
The Sandians first established a formal test protocol, then conducted the test March 20 in a remote Sandia area on Kirtland Air Force Base. Five large plastic packing crates were set up in a line at 30-ft. intervals. The goal was to see if a test operator, using the instrument, could detect someone concealed inside only one of the five crates. The operator was provided by the DielectroKinetic Laboratories and was a high-ranking member of its management.
The test was double-blind and random. Neither the instrument operator nor the three Sandia investigators knew which crate contained the human test subject until after the test results were tabulated.
The test set-up manager used a sealed, randomly generated test schedule to direct the test target (the human) into one of the five containers. Using the device, the test operator then attempted to determine which container the human was in. The DKL operator “scanned” the crates from a distance of 50 feet, well within its stated capabilities.
First, a baseline evaluation was done to see if the instrument appeared to be “operating correctly.” The operator and the investigators were all allowed to see which container the human test subject entered.
Under this noncontrolled condition — when the instrument operator already knew which crate contained the human — he was quickly successful 10 times in 10 trials. The same was true, of course, for everyone else present.
All subsequent tests were controlled. The test operator did not see which crate the test subject entered. Nor did the Sandia investigators. No one learned the full results until the entire set of tests was completed.
A one-in-five probability of success
For each trial, one human test target was inside one of the five crates. The operator had a one-in-five probability of success by chance alone. Under these conditions, say the Sandians, the test operator began taking a much longer time to “scan” the crates.
The tests were spread over about four-and-one-half hours of set-up and test time. The DKL operator had just six successes in 25 trials.
A third test series was similar but a little more complicated. Multiple human targets could be randomly hidden in crates. But, again, the results were consistent with random chance.
The Sandians say the test operator offered several rationalizations for the difficulty of detecting the test subject and for the chance test results under controlled conditions. He said, for example, that the “sharp edges” of the crate were distorting the field and were interfering with the detection. However, the Sandia investigators point out that the manufacturer’s published capabilities for the device include statements such as “penetrates all forms of camouflaging” and “no known countermeasures.”
Although the empirical test was the core of the analysis, the Sandia team also briefly examined DKL product literature about the advertised physics behind its operation. The product literature says the instrument antenna detects the electrical field generated by the beating human heart, but the Sandian team found the idea put forth for that process “clearly wrong.”
The Sandians point out that the heart beats at a rate of 1.2 to 2.0 hertz and the wavelength of two hertz is 93,150 miles. “The 15-inch antenna on the LifeGuard is entirely inadequate for receiving signals of that wavelength,” they report.
Cannot perform any better than chance
“These points about the physics of the device support the conclusion of the results of the empirical tests,” they say. “The device cannot perform any better than chance.”
Murray, Floyd Spencer, and Debra Spencer wrote and submitted to DOE a 10-page report titled “Double-Blind Evaluation of the DKL LifeGuard Model 2.”
The Sandians came to a clear conclusion: “Our evaluation of the DKL LifeGuard, although brief, leads us to conclude that the device performs no better than random chance. Although we only had time to evaluate the device with one test operator, that test operator was from the DKL organization, was selected by the manufacturer to perform that evaluation, and spent considerable time trying to use the device to the best of his ability. Thus, we conclude that no other test operator would be able to establish a better performance of the instrument except by chance.”
Technical Contact:
Dale Murray, dwmurra@sandia.gov, (505) 845-8952