GPS is a doddle to hack
If you have the readies
HACKERS CAN BRING down aircraft by spoofing their Global Positioning System, boffins at Cornell University and Virginia Tech have warned.
Brent Ledvina of Virginia Tech said there is shedloads of infrastructure based on GPS and it is wide open to hackers. Ledvina even built a spoofer to show weaknesses in the system.
He said that a GPS receiver detects signals from about 30 orbiting satellites. Based on the time it takes for the signal to reach the receiver and the direction it came from, the receiver can triangulate an exact time and place, down to hundreds of nanoseconds.
All a hacker has to do is create a false GPS signal that passes as a real GPS signal, and an incorrect time or location appears on the intended receiver.
Apparently being 10 microseconds off could cause power generators to explode, planes to crash into each other, financial transactions fail, criminals to avoid capture, and Osama bin Laden to be the next US president.
A spoofer is not cheap to make. It requires about $1,000 worth of hardware and it has cost the boffins about $1 million to research.
The spoofer device is the size of a briefcase and is plugged into a wall socket. It can be used to bring down a plane at your leisure. Available soon on iwoot.com, no doubt. µ
L’Inq
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Comments
007
was this copied from James Bond?James Bond?
Wasn't there a Bond movie about this?Airliners don't rely solely on GPS
Too bad this is all sensational journalism and you can bring down any commercial aircraft by falsifying the GPS signal because no airliners uses GPS as the only source of navigation.Instead aircrafts navigation system constantly cross-check their position using conventional VOR-DME fixes, their own build-in inertial reference system (IRS/INS) and on top of it the GPS signal received.
The IRS, which has no outside connections, is precise enough to fly for 12-16 hours straight and still be able to determine the exact position within a quarter mile if no VOR-DME fixes are possible within that time period.
Also, GPS approaches are still not certified for the only means of performing a approach and landing within commercial operations and won't be for another few years, so no, a faked GPS signal won't bring any airliners down, not now and not in 10 years.
You'd think
There would be a simple voting system, where if one "satellite" (the spoofer) doesn't agree with the 5-7 other satellites the receiver is locked on, it gets tossed out.Sure
Anybody that ever used a GPS system in his/her car knows it demands a fix on a number of satellites before it deems the location info reliable, and that's a cheap car system, I assume a plane has even higher demands, as well as crosschecks.So I don't see how 1 fake transmitter would do much damage, and I'm sure the army will be on such a suitcase in minutes and have a nice chat with the one carrying it, or a 500 pound package delivered if that's not possible.
ok
then send out 5 fake signalsThinking is easy
The signal from the spoofer device impersonates a whole handful of satellites, not just one. Most, if not all, GPS systems have no way to verify the direction the signal comes from. So, the spoofer sends fake signals from all possible satellites at once, with time delay offsets for each fake satellite that are just enough to convince the GPS unit of the spoofed course.Since the briefaces is over 1000x closer to the GPS receiver than the actual satellites, its signal will override the real GPS signals.
Word of thanks
Thanks to the commenter(s) explaining the suitcase sends out 5 fake signals, but nevertheless, since the US army runs the GPS system, and it's very obvious a hostile act (as well as a federal crime) to do such a thing as described, I can tell you I would not want to be the one standing there with that suitcase, although I suppose you could plant it somewhere with a delayed activation, but that still leaves the crosschecks planes do with other sources and telemetry.Also didn't the GPS system take that into account? don't I recall there was some encryption involved, and that there was higher precision for those allowed?
I guess it's time to hit wikipedia if I want to know.
Planes don't rely .....
In my military experience, inertial navigation systems (INS) are unreliable and pilots have quickly learnt the GPS is 'always' right and so ignore them.What about the bombs and missiles that rely on GPS. Well at least the Americans would be able to have a new excuse why their ordance hit the wrong target.
Link to the article
You might want to add the link to the Virginia Tech News article on this research, which is at http://www.vtnews.vt.edu/story.php?relyear=2008&itemno=578 (but then, I guess I've just added it, though it would be more visible in the body of your column).Who runs the GPS system?
Minor point, but GPS isn't run by the US Army. It's run by the US Air Force.