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Road pricing GPS signal jammers ? What about cheap GPS position spoofing devices ?

The Times reports again on the wishful thinking by the Department of Transport that there will somehow be a magical technological fix to the fundamental flaws in their self inflicted National Road Tolling schemes.

£700 in-car box would jam spy-in-sky road toll satellite

Ben Webster, Transport Correspondent

The Times , August 8, 2007

Motorists who want to evade pay-as-you-drive tolls are being offered a new device that would shield their cars from the satellites used to track their movements.

But those tempted to pay £700 for the small metal box, which plugs into a car’s cigarette lighter, will find that the Government is already devising ways of catching those who try to cheat the system.

Nothing has changed since our discussions on Spy Blog about this topic back in 2004, when Alistair Darling, who is now the Chancellor of the Exchequer was promoting the plan, without any clue about the limitations of the technology.- Alistair Darling's satellite tracking road toll plans - another Big Brother surveillance system


The jamming device emits a signal that would prevent the black box from communicating with the satellite. The charging system would assume that the car was stationary even when it was moving and would not charge the driver for journeys.

But a DfT spokesman said that the team preparing for the introduction of tolls had considered how to prevent drivers from using such devices.

He said: “There is no point in using one of these devices because while they may block the satellite signal they do this by broadcasting their own signal which can easily be detected.”


Really ? How ? The GPS signal from the satellites in orbit is incredibly weak by the time it gets to the surface of the earth, and it does not take much power to jam or spoof the local signal within a vehicle, especially with the use of some cheap metal shielding to cut off the real satellite signal from the "black box" antenna..

If such In Car Units for Road Tolling are ever inflicted on millions of motorists, there will be not simply crude GPS jamming devices but GSP signal spoofing devices which will feed GPS coordinates into the In Car Unit which appear to show genuine journeys in zero or low tarriff zones or during off peak time periods.

If the Government goes ahead with these creepy mass surveillance plans, then these undetectable GPS spoofing devices will be available at far lower cost than £700, due to the economies of scale.

Remember also, that once the market for such electronic devices has been artificially created by the Government bureaucracy, they will also be used directly or adapted for use, by convicted criminals and unconvicted terrorist suspects etc. who are electronically tagged with combined mobile phone / GPS satellite electronic tags who will be able to fool the weak monitoring systems to a greater extent than even now.


OK, so the government are planning to crack down on people jamming the signals. Fine, so how's about using this as a form of terrorist attack?

Here's how you do it: build a lot of ultra-cheap boxes which're mostly batteries, plus a jamming circuit and a timer system identical on all of each production run of boxes. Disguise each box as a clod of earth, or similar.

Next, having set a series of pseudo-random on-off periods timed to coincide with rush hours a few days a week, plant the devices on motorway embankments closely enough that a few kilometres of road will suffer a complete jamming white-out when the units trigger synchronously.

Now, when they units all go off, hundreds of cars all get their signals jammed, and hundreds of tracker boxes all report back to Big Brother that they are being jammed and it is time to give their owners a short, unpleasant visit from PC Plod.

Result: hundreds of people get unjustly accused of box-tampering. Thousands of man-hours of police time gets wasted. Hundreds of people get bloody annoyed with the government and the government gets an even greater reputation for utter incompetence.

Nobody dies, nobody gets hurt, but a tremendous amount of stress is caused and a tremendous amount of adverse publicity gets aimed at the government. Mostly harmless terrorism, in effect.

@ Dr Dan H - that would probably be sufficient to be fall under the draconian
Terrorism Act 2000 Section 1 Terrorism: interpretation, subsection 2

(e) is designed seriously to interfere with or seriously to disrupt an electronic system.

There is also the catch all Terrorism Act 2006 section 5-Preparation of terrorist acts, under which

(3) A person guilty of an offence under this section shall be liable, on conviction on indictment, to imprisonment for life.

The bureaucracy has no sense of humour where it can invoke the Fear, Uncertainty and Doubt of "terrorism".

Surely it cheaper for the motorist to disable the vehicle's G.P.S tracker, by;

Firstly, the unit's internal electronics can be scrambled using a couple of powerful magnets place either side of the unit's casing.

Secondly, the unit's transceiver can be shielded using lead flashing used for roofing.

DIY GPS Jammers



Even tracking down a bit of malfunctioning equipment which is inadvertently jamming GPS signals, takes a lot of effort.

This example involves a boat in a harbour in California, which affected the whole area for a month, until tracked down by experts from the nearby oceanographic research institute:

Unjamming a Coast Harbor
Jan 1, 2003
By: James R. Clynch, Andrew A. Parker, George Badger, Wilbur R. Vincent, Paul McGill, Richard W. Adler
GPS World


We contacted the boat owner and gained access, quickly determining that the emitter was a commercially available VHF/UHF television antenna with built-in preamplifier. The antenna was powered by an AC/DC adapter plugged into boat AC power. The preamplifier was thus powered all the time, even when the TV was not on. In fact, the TV was seldom on, and most of the time the TV antenna was in a paint locker inside the locked boat. From this interior location, its emissions jammed all of Moss Landing Harbor and an area at least 1 kilometer out to sea


An industry source tells me that thinking has moved in the direction of tag and beacon as the next generation of technology to be deployed. This will be combined with ANPR in many locations. Such methods align with concentrating on urban area congestion charging (and perhaps some motorways as well) rather than blanket 100% geographical coverage. They also recognise the difficulties with GPS in urban canyons and/or where different classes of roads are very close together.

It worries me that we're already looking for ways to jam the technology rather than simply refuse - on mass - to go down the road of paying for road transport by the inch...

I started this group on yahoo to show how easy it is to take an unsecured system such as GPS receivers are, and cause them to misreport your location.

This device I havce designed gives you the ability to change your location in an 'etch-a-sketch' fashion.

You need to have access to the interface between the GPS receiver and the reporting device though.

Private backers seem to have all but pulled out of the Gallileo system system but governemnts are frantically trying to pay for it for themselves. I wonder what else Gallileo can do other than transmit a simple time signal ?

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