Ithaca (NY) - Researcher teams led by Paul Kintner and Mark Psiaki at Cornell University have demonstrated that suitcase-sized transmitters could be employed to fool even commercial and military GPS units. By sending out "false authentic" signals in close proximity, those which mimic true GPS satellites, over time GPS receivers begin to accept the false signals as genuine and report improper position data to the user.  Concerns over personal, commercial and military implications of the false data are the focus of the study.




GPS

The GPS receiver is enabled by a system of 30+ satellites orbiting the Earth twice per day in specific, known orbits. Those satellites transmit positional, timestamp and authentication data toward the Earth where every GPS receiver within reception range can pick it up.  Information from at least four of these satellites is required to accurately compute positional data, though five or more is typically preferred.

Consumer-based GPS receivers are accurate to within a dozen meters or so.  Much more expensive commercial GPS units can be accurate to well under a single meter.  And military GPS units can be completely accurate to within centimeters or even millimeters.  This disparate level of reporting has to do with the sensitivity, timing and compute capabilities of the receiver.

Most consumer applications don't need to be more accurate than 30 feet or so.  It's very cheap to be that accurate and most cell phones today even come with this level of accuracy built-in via a tiny chip.  It gets much more expensive very quickly to be more accurate.

Consumer devices often detect movements of just a few inches and report them.  When I hold my Magellan GPS unit in my hand and move it around within arm's length, it identifies the direction of travel and speed very accurately.  But, the actual reported position it's showing me may be 30 feet or more away from the real, 100% true positional location.  Two or more consumer-based products would also likely report slightly different values for a given location, though both of them would detect even very small movements.

Commercial GPS units are available for trucks and farming.  These are typically accurate below a half-meter and cost several thousand dollars.  For example, John Deere's high-end StarFire Receiver uses up to 10 satellite channels as well as ground-based assist signals.  These are accurate to within 4 inches (depending on model).  Devices like these cost over $10,000 and are used for tractor AutoSteer and programmable fertilizer deposition (which also coordinates satellite data as to how much fertilizer is needed where on the farm).

Once everything is setup, farming today witch such machinery just requires you to click "Go."  The tractor does the rest.


Concerns over industry

The real concerns here aren't for consumers carrying their in-auto navigation systems on a road trip, though that is also a concern.  The real concerns are for the commercial industries.  So many industries now rely on GPS data for pinpointing problems, visiting specific jobsite locations (such as a drill site or underground cable site), and much more.  Were false readings given on their GPS devices, they could be unable to find something necessary to keep an industry going.

Suppose a terrorist took out an electrical control box or Internet backbone in the middle of nowhere.  The computer immediately recorded the outage, its location (by relay station) and dispatched repair crews.

Unless the repair personnel knew the exact location of the damaged spot (because they had real maps, or had previously been there), they would be relying on GPS data to put them at the right place.  And with inaccurate GPS data it could be chaos trying to find the true location of the damaged device, resulting in countless civilians being affected far longer than need be.


U.S. Government has thought of this

Two additional co-authors of a paper describing the techniques used to create these false signals, Brent Ledvina and Todd Humphreys, refer back to a December, 2003 report by the U.S. government which details seven possible countermeasures to ward off such an attack.  Humphreys said, "We're fairly certain we could spoof all of them, and that's the value of our work."


Goal is to do GPS better

Both authors have said, "Our goal is to inspire people who design GPS hardware to think about ways to make it so the kinds of things we're showing can be overcome."  Today, it is possible to fool our GPS units quite easily with something the size of a suitcase.  Will this research spawn our scientists to develop false signal resistant GPS receivers?

if there is ever a bunch of fake signal...

Sep 23, 2008 14:21     

won't our gov be able to track who is jamming the signal? it's probably quite easy to track them if they have to continously sending out incorrect signal..... that guy will get caught in no time... plus the artical still don't point out what else is that important if we lose the commercial signal...since really, if I lose my car GPS...no harm done... the worker went to wrong location...that happens all the time... And for military ones...I think they use different GPS that has authantication...

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"Suppose a terrorist ..."

Sep 24, 2008 06:31     

Terrorists are now like wolf or witches during middle age : you can imagine marvelous stories, make them do unprobable things... and make money from these impossible tales... And make people vote for you because of the constant fear they are bathing in. In fact real terrorists are using good old explosives, killing innocent people (usually muslims by the way) in foreign countrys, not using high tech gadgets to disrupt tractors in the corn fields of the US... but business is businees, and the fear factor is a good selling stuff.

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gps

Sep 24, 2008 07:49     

a gps is great and all, but it is like any other technology; a tool, not a replacement for comon sence. I got a new gps about 6mo ago, and though it makes navagating columbus, cincy, and louisville easier I cant tell you how many times it tries to take me down a road that dosnt exist yet, has long been closed, or will never ever ever exist. Thats not to mention roads that it thinks connects to other roads but dont, or takes me the long way arround what looks like a good shortcut only to find out that it does in fact connect now. True, these instances are rare (and fool me once shame on garman, fool me twice shame on me), but a false signal isnt going to cause me any major issues, or anyone else for that matter (the gps is mostly to have something to distract you and keep you awake anyways). And as andy said, the military uses a verrified unscrambled signal which would be difficult to tamper with, and airline pilots are not likely to say "hey, that building looks like a landing strip". There is always still the human inteligence factor to correct when our tools fail us.

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