UK Sentinel study reveals GPS jammer use

Government-funded trials involving the police have revealed more than a hundred incidents of GPS jammer use in the UK.

The Sentinel project, which has been running since January 2011, was designed to measure GPS jamming on UK roads. The project, run by GPS-tracking company Chronos Technology, picked up the illegal jamming incidents via four GPS sensors in trials lasting from two to six months per location.

The government-funded Sentinel project has uncovered more than a hundred incidents of GPS jammer use in the UK since January 2011. Image credit: Tom Espiner

"The idea behind Sentinel is to detect and locate interference," Chronos Technology's divisional manager Andy Proctor told ZDNet UK on Wednesday. "Until you physically get a jammer in your hands you can't claim 100 percent it's a jammer, because you don't know what's been causing the interference."

The Sentinel field trials of GPS jamming involved sensors in different locations. One sensor placed in a city next to some docks and a two-lane link motorway found 67 incidents of vehicles using GPS jamming over a six-month period, according to Chronos Technology's managing director Charles Curry.

"These events were real and corroborated," Curry told ZDNet UK at the GNSS Vulnerability: Present Dangers, Future Threats 2012 conference.

GPS jammers work by broadcasting a strong local signal on the same frequency as GPS, effectively drowning the weak GPS signal broadcast by satellites. People illegally jam GPS for a number of reasons, Curry told the audience at the conference at the National Physical Laboratory. These include evasion of company-vehicle or covert tracking, and stealing high-value vehicles.

In prior trials, a white van driver using GPS jamming had been apprehended by police, said Curry. The man, who was not brought to trial, was using jamming to evade company GPS tracking. ZDNet UK understands the man was apprehended as part of trials of GAARDIAN, a preceding technology to Sentinel. GAARDIAN trials ran from 2008 to 2011.

Sentinel project

Sentinel now has 20 sensors deployed in different parts of the country, Curry told the conference. The £1.5m Sentinel project is funded by the ICT Knowledge Transfer Network, and its partners include ACPO, Ordnance Survey, the National Physical Laboratory, the General Lighthouses Authority (GLA), the University of Bath, and Thatcham Security. Sensors tend to be deployed in premises owned by these organisations.

The Sentinel technology works by relaying incidents of GPS interference to a central server, Proctor told ZDNet UK. The sensor is a black box that contains a high-sensitivity GPS sensor, in some cases a rubidium atomic clock, and an embedded Linux processing unit running proprietary software using C++, PHP, and a MySQL backend database.

The eventual aim of the Sentinel project is to pinpoint GPS jamming.

GPS jamming and spoofing can have serious effects on geolocation and communications technologies that rely on GPS for positioning and timing; maritime and aircraft GPS use, and even stock market trading, can be affected by jamming, researchers said at the conference.

THV Galatea trial

In 2009, the Ministry of Defence conducted trials of GPS jamming against the THV Galatea, a buoy tender, in an area of sea near South Shields in the north of England, Professor David Last told the conference. The jamming caused the ship's systems, which were reliant on GPS, to malfunction.

Our modern society is almost completely reliant on GPS. It could be deadly.

– Todd Humphreys, University of Texas

During the trial the ship gradually lost position, and the autopilot told the ship to move off course, said Last. "Ships carry multiple [GPS] receivers embedded in multiple systems in ways people on board do not understand," Last told the conference. "When one system fails, they all fail."

This single point of failure can affect both navigational and communications instruments, Last told ZDNet UK. Instruments affected aboard the Galatea included the main electronic chart display, which was linked to the autopilot; the ship's automatic identification system; voice and data communications; and the helicopter-pad stabilisation system.

"The ship's position silently departed from the truth, and the ship's autopilot silently began to turn the vessel," said Last.

Reliance on GPS

GPS jamming and spoofing can also affect aircraft GPS and stock exchange transactions, according to University of Texas researcher Todd Humphreys, who gave a presentation at the conference.

"Our modern society is almost completely reliant on GPS," Humphreys told the conference. "It could be deadly."

Stock exchanges could be adversely affected by GPS jamming and spoofing because their datacentres rely on GPS signals to timestamp transactions, Humphries said. Any confusion caused by disruption to timestamps could cause traders to withdraw trades, he said.