GPS Can Be Spoofed

Air Safety Week, Sept 29, 2008

Just like flat-screen televisions, cell phones and computers, global positioning system (GPS) technology is becoming something people can't imagine living without. So if such a ubiquitous system were to come under attack, would we be ready?

It's an uncomfortable question, but one that a group of Cornell researchers have considered with their research into "spoofing" GPS receivers.

GPS is a U.S. navigation system of more than 30 satellites circling Earth twice a day in specific orbits, transmitting signals to receivers on land, sea and in air to calculate their exact locations. "Spoofing," a not-quite-technical term first coined in the radar community, is the transmission of fake GPS signals that receivers accept as authentic ones.

The researchers, led by Cornell professors Paul Kintner and Mark Psiaki, programmed a briefcase-size GPS receiver, used in ionospheric research, to send out fake signals.

The phony receiver was placed in the proximity of a navigation device, where it tracked, modified, and retransmitted the signals being transmitted from the GPS satellite constellation. Gradually, the "victim" navigation device took the counterfeit navigation signals for the real thing.

By demonstrating the vulnerability of receivers to spoofing, the researchers believe they can help devise methods to guard against such attacks.

The idea of GPS receiver spoofing isn't new; in fact, the U.S. government addressed the issue in a December 2003 report detailing seven "countermeasures" against such an attack.

But, according to the researchers, such countermeasures would not have successfully guarded against the signals produced by their reprogrammed receiver.

"We're fairly certain we could spoof all of these, and that's the value of our work," they said.

[Copyright 2006 Access Intelligence, LLC. All rights reserved.]