WASHINGTON – Watch your step! The Pentagon is developing a radar-based device that can identify people by the way they walk, for use in a new antiterrorist surveillance system.
Operating on the theory that an individual's walk is as unique as a signature, the Pentagon has financed a research project at the Georgia Institute of Technology (search) that has been 80 to 95 percent successful in identifying people.
If the Defense Advanced Research Projects Agency (search), or DARPA, orders a prototype, the individual "gait signatures" of people could become part of the data to be linked together in a vast surveillance system the Pentagon agency calls Total Information Awareness (search).
That system already has raised privacy alarms on both ends of the political spectrum, and Congress in February barred its use against American citizens without further congressional review.
Nevertheless, government documents reviewed by The Associated Press show that scores of major defense contractors and prominent universities applied last year for the first research contracts to design and build the surveillance and analysis system.
DARPA is the federal agency that helped develop the Internet as a research tool for universities and government contractors. Its newest project is massive by any measure.
In its advice to contractors, DARPA declared, "The amounts of data that will need to be stored and accessed will be unprecedented, measured in petabytes."
One petabyte would dwarf most existing databases; it's roughly equal to 50 times the Library of Congress, which holds more than 18 million books.
Conceived and managed by retired Adm. John Poindexter, the TIA surveillance system is based on his theory that "terrorists must engage in certain transactions to coordinate and conduct attacks against Americans, and these transactions form patterns that may be detectable."
DARPA said the goal is to draw conclusions and predictions about terrorists from databases that record such transactions as passport applications, visas, work permits, driver's licenses, car rentals, airline ticket purchases, arrests or reports of suspicious activities.
Other databases DARPA wants to access include financial, education, medical and housing records and biometric identification databases based on fingerprints, irises, facial shapes and gait.
TIA is an effort to design breakthrough software "for treating these databases as a virtual, centralized grand database" capable of being quickly mined by counterintelligence officers even though the data will be held in many places, many languages and many formats, DARPA documents say.
One goal is to provide "focused warnings within an hour after a triggering event occurs," the documents say.
Poindexter's plan would integrate some projects DARPA has been working on for several years, including research headed by Gene Greneker at Georgia Tech.
At a cost of less than $1 million over the past three years, he has been aiming a 1-foot-square radar dish at 100 test volunteers to record how they walk. Elsewhere at Georgia Tech, DARPA is funding other researchers to use video cameras and computers to try to develop distinctive gait signatures.
"One of the nice things about radar is we see through bad weather, darkness, even a heavy robe shrouding the legs, and video cameras can't," Greneker said in an interview. "At 600 feet we can do quite well."
And the target doesn't have to be doing a Michael Jackson moonwalk to be distinctive because the radar detects small frequency shifts in the reflected signal off legs, arms and the torso as they move in a combination of different speeds and directions.
"There's a signature that's somewhat unique to the individual," Greneker said. "We've demonstrated proof of this concept."
The researchers are anticipating ways the system might be fooled.
"A woman switching from flats to high heels probably wouldn't change her signature significantly," Greneker said. "But if she switched to combat boots, that might have a difference."
The system could be used by embassy security officers to conclude that a shadowy figure observed a few hundred feet away at night or in heavy clothing on a Monday, Wednesday and Friday was the same person and should be investigated further to see if he was casing the building for an attack, Greneker said.
At a restricted facility, the technology could warn security officers that an approaching person was probably not an employee by comparing his gait with those on file. "And we now know how to detect people who are carrying heavy packages, which could include a 25-pound bomb in a backpack," Greneker said.
Greneker hasn't gotten caught up in the privacy debate. "We are research and development people. We think about what's possible, not what the government will do with it. That's somebody else's job. And this isn't a weapons system."
DARPA contracting records made available through a Freedom of Information lawsuit filed by the Electronic Privacy Information Center, a privacy advocacy group, show Poindexter agreed to fund 26 research projects and rejected 154 others through last Dec. 4. Other DARPA contract award data were released under FOIA to the Center for Public Integrity, an ethics advocacy group.
One of the largest was a contract for up to $27 million to Veridian Systems Division of Arlington, Va., to design software to allow "intelligence analysts and decision makers to jointly participate in the development of a full range of contingencies."