GPS Vulnerability Articles

Financial Times:  By Peter Whitehead, Digital Business editor

Published: February 23 2010 16:58

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Critical infrastructure, including air traffic communications, electricity transmission, telecoms networks and emergency services are all under threat from the increasing availability of "GPS jammers", technology experts are warning.

"A portable jammer in a tall building could cover most of London and aircraft approaching its airports," said Professor David Last, a past president of the Royal Institute of Navigation and now a GPS consultant.

Global Positioning System signals, which are extremely delicate, are now relied upon by vital sectors, including transport, just-in-time manufacturing and farming.

Prof Last told a symposium, organised by the Digital Systems Knowledge Transfer Network, that by using GPS a single person could today control a huge vessel sailing in crowded shipping lanes at 25 knots.

But as reliance on GPS for such tasks increases, traditional back-up systems are falling into infrequent use and traditional navigational skills are declining, leaving organisations vulnerable to interference with GPS signals.

The dangers can be unintentional, caused by solar flares or accidents, or intentional, with a fast-growing criminal element.

"The strength of a GPS signal is about as strong as viewing a 25W light bulb from a satellite 10,000 miles away," said Bob Cockshott, a director of the Digital Systems KTN. "It's no surprise then that GPS signals are vulnerable to natural and, increasingly, criminal interruptions."

Jamming devices that can disrupt GPS signals are sold on the internet for less than £100. Prof Last said they could be used by thieves to block transmissions from stolen vehicles protected by GPS tracking systems, rendering them "invisible". Crooks might even transmit a false location using a "GPS spoofing" device.

He said he had also heard of disgruntled employees buying jammers to defeat tracking systems installed in their cars by employers.

"These devices are selling; terrorists have been arrested with them," he told the symposium. "GPS now is like computers before viruses. But there are no big security companies working to protect GPS."

Alan Grant, a radio-navigation expert with the General Lighthouse Authorities, gave an example of how a blocked GPS signal could produce dramatic results: in a jamming experiment off the coast of north-east England, instruments monitoring ships' positions showed them sailing over land at speeds of thousands of knots.

Dr Grant said such obvious deviations were not the problem: "It's the small deviations that pose the biggest risk."

The effect on personnel was equally surprising: "The ship's crew knew they were taking part in a trial and so were expecting things to go wrong, yet their first instinct was to keep checking the GPS. They were far less familiar with alternative systems."

GPS vulnerability is being investigated by the Gaardian project that brings together industry and academia. Charles Curry, managing director of Chronos Technology, is leading the investigation consortium and he believes back-up systems are vital.

"Our project creates a network of sensors deployed at sites in the vicinity of applications that rely on the GPS signal. We are then able to monitor any change in the signal due to natural or criminal activity," he said.

The Royal Institute of Navigation stresses the importance of developing a ground-based back-up to global navigation satellite systems (GNSS): "There is a necessity for robust, terrestrial based systems to provide a concurrent, independent source of position and time information to ensure navigational safety and environmental protection."