02/13/03 19:47 ET

Satellites and super-sensitive sensors are now tuned to the sibilant hiss of spray cans in a space-age effort to eradicate one of the oldest and most persistent urban problems -- graffiti.

TaggerTrap, a graffiti eradication system being tested in several California cities, uses global positioning system technology, cell phones and sensors that recognize the ultrasonic pitch of spray cans to alert police when vandals begin their work, representatives said Thursday.

"The tagger, when he pushes down on that spray can, he's calling police," said George Lerg, co-founder of TrapTec, the Escondido, California-based company that developed TaggerTrap.

The unique, ultrasonic tone emitted by aerosol paint cans trips the sensors, which signal a transmitter linked to a police cell phone or radio. The global positioning system pinpoints the location of the transmitter, Lerg said.

The portable sensors have a range of 100 feet in any direction.

The first time TaggerTrap was tested in the San Diego suburb of Chula Vista, police arrived in time to nab a six-person graffiti "crew" in the act.

The system quickly drew the interest of three nearby Southern California cities, which plan to test it themselves.

"Just from the test I have seen and word from Chula Vista it has worked wonderfully," said Officer Judy Ronnebeck of the Escondido Police, adding that the $2,000 price tag for each unit seems a small price to pay for space surveillance.

"Our city spent over $150,000 last year cleaning graffiti," she said. "The more money it costs to clean it up, the more people realize we have to make these taggers responsible for their actions."

Lerg said TaggerTrap and the company's other products -- systems that warn police of gunfire and trucking dispatchers of leaking tires -- have caught the attention of the U.S. Department of Defense, which has drafted the technology for other national security applications.

"The government is extremely concerned about biotoxins inside aerosol cans that can be put into air-conditioning ducts of a subway system or a large building," he said. "If somebody is using an aerosol can where they shouldn't be, we can notify authorities.

The city of San Diego, which spends about $1.5 million on graffiti cleanup each year, has also tested the system, said Sonya Ollison, in charge of the city's graffiti removal.

The latest estimate is that graffiti causes $8 billion in damages across the nation per year, Ollison said.