Moonlighting van drivers are probably to blame for the growing problem of GPS jamming on Britain’s roads, the latest survey of the problem by the Technology Strategy Board’s Sentinel Project has suggested.

In advance of today’s Global Navigation Satellite System (GNSS) Vulnerabilities 2013 event, the organisation revealed its network of sensors had recently detected up to 100 potentially dangerous jamming incidents a day near one busy UK airport alone.

When trying to work out what might be causing such a high level of interference, the project engineers noticed that most of it occurred during the week, dropping off at weekends, which ruled out solar weather events that occur more randomly.

Jamming was also most marked during rush hour which pointed to commercial vehicles being the culprits rather than, as previously suspected, vehicle thieves trying to foil security tracking systems.

“The pattern of behaviour suggests it is likely to be civilian-sourced jamming and most likely the evasion of tracking within commercial vehicles for moonlighting activities or for other non-work purposes,” said project head and Chronos Technology founder, Charles Curry.

The best guess is that van drivers want to hide unauthorised use of delivery vans, using jammers to confuse the central tracking software now used by all major delivery networks to optimise the supply chain.

A year ago, the Government-funded Sentinel Project first reported on the issue of GPS interference, using its network of sensors placed on bust roads to log what had previously been a largely anecdotal problem.

And problem it is; GNSS is critical for aviation and air traffic control, shipping, and specific applications such car tracking to deter theft; consumers also use it for SatNav. Jamming can cause significant problems for these applications.

The underlying cause is the easy availability of cheap 12-vollt jammers, which can cost as little as £30 each and a widespread ignorance about their unintended effects on critical systems.

The separate Stavog project ran simulations that confirmed that these devices could cause outages across all GPS systems on the market, causing data inaccuracies that commercial users might not realise was even occurring.

“Even the cheapest ones [jammers] available online can cause complete outages of the receiver signal,” said Stavog project manager, Dr Chaz Dixon.

“It is in anticipation of this threat that we will be making this service available for any GPS users to understand and protect themselves against the vulnerabilities in their positioning and timing systems,” he said.

Both Sentinel and Stavog will present their full survey findings at today’s GNSS Vulnerabilities 2013: Countering the Threat event, held at the National Physical Laboratory.

"Our more complete understanding of the risks posed to GNSS systems is bringing forward new mitigation technologies and approaches,” commented  conference organiser and director of position, navigation and timing at the ICT Knowledge Transfer Network , Bob Cockshott.

“There is no one solution that fits all. Instead we need to combine the right protection and back-up technologies with legal reforms which punish the ownership and use of these jammers, and finally advise government and industry on new commercial and civil policies that will reduce the incentive to jam in the first place."