The risk these things pose to aviation is real. There's been a huge shift towards GPS for instrument flying. Cross country flying frequently relies on GPS to know where you are. Even more important, flying an approach to land now often uses GPS to keep the plane to a specific safe path, essential when flying in a cloud. A plane isn't going to fly out of the sky if GPS suddenly stops working, but it can make life awfully difficult.
The risk is not just theoretical. For example, in 2009 the Newark airport had a daily GPS failure that was finally traced to a trucker using a jammer, presumably to defeat a tracker enforcing safe driving rules. http://www.economist.com/node/18304246
The more sophisticated jammers don't cause "noise", but rather they record and replay the pseudorandom generated digits they receive from the various frequencies and time drift them. It's hard to triangulate much of anything then and it could send you off miles from where you think you are.
Much better than just noise because you wouldn't know there is a problem.
This attack is what Iran says they did to capture the US drone a few months ago. It's pretty crazy that GPS signals include no cryptographic authentication, even for military use.
I'm not so worried about this kind of attack on civilian aviation. It would be a directed attack: potentially deadly but rare and focussed. I'm much more worried about the casual disruption to GPS from truck drivers spending $99 on a grey market device.
There is cryptographic hash so that you can't send false data, but replaying the existing data but time delayed is still possible. The timing is how the triangulation fix is done. More sources of data, the harder it is to spoof. If you only have 3 or 4 fixed points, it's easy to spoof. 6 to 10 and it becomes extremely difficult.
Also military GPS is far more accurate than civilian GPS by a factor of 10x.
I'm speaking out of ignorance here, but why couldn't you just use a quantitized time value (to account for transmission lag) as a part of the data that's hashed? It works great to prevent replay attacks with OAuth.
nope. it's time that is the factor for triangulation. you always take the first time you received from the one source and you can discard certainly something way out side of what you expect. It's how you defeat the concreate canyon effect in big cities where signals are bouncing off everything.
However if you have a low strength signal from one source and you receive a frame that is a second or a two off, it can cause you to think you are miles away from where you think you supposed to be.
"military GPS is far more accurate than civilian GPS" - is this still true? I don't know how my iPhone GPS triangulates me, but it usually has me located to within 3-5' at all times when I'm walking home.
That has nothing to do with why the iphone is so fast.
Civilian transmission rates on L1 are 10x slower than the military L2 frequency. It takes a full 6 seconds to get a single frame downloaded and that is also hoping your almanac is up to date. (Thankfully AGPS can provide the almanac data by other menas.)
The military version it takes .6 seconds to do the same it takes us civilians to do in 6 seconds. The SA drift is gone now but still the slower speed makes fixing a perfect position slightly more difficult and less accurate.
I just saw a demonstration a few days a go by the UT Austin Radio Navigation lab where they spoofed L1 GPS and caused a radio controlled helicopter to somewhat precisely veer off course. I'm interested in the impact of this on aviation as well.
I really appreciate the link they provided at the end of where to buy one.
These personal sized units are not really a risk to aviation etc as is being said, that is just an argument to make the public turn against the freedom from unwanted surveillance that jammers bring. These work by transmitting noise at the frequencies that the GPS satellites transmit at so the local receiver can't tell where it is, which is the same as when it's in a tunnel or parking garage. The range on these battery operated personal ones is only a few feet, so no naval ships or airplanes thousands of feet or miles away are bothered. The ones that bother fishing boats and such are high powered transmitters designed to block other parties at a distance and have nothing to do with these small ones people use to stop their boss knowing what they are doing with the company delivery truck.
the problem is that the legitimate GPS signal is ridiculously weak, and generally speaking, to reliably jam, you need a significantly stronger signal. (well, and compared to a solar-powered transmitter on a satellite, it's pretty hard not to have a significantly stronger signal) I'm not a RF guy myself, but I hang out with a bunch of them. Guaranteeing that your jammer only had a range of a few feet sounds... difficult.
I personally know people that have had problems with their systems that have been traced back to truckers with GPS jammers.
Just reading the article rather than relying on other sources, this sounds like the sort of report used to justify one or more additional government contracts in the name of "national security".
To put it another way, the only solution is already known - build critical systems which are not dependent on continuous access to GPS signals. One cannot prevent jambing of a widespread consumer system - the asymmetry of costs and knowledge is too far in favor of the jammer in any civilian case (military solutions to jamming are another matter).
I'm UK based and I think we do have a tendency in the UK towards low redundancy in key systems, mainly to save money.
For example, the London Underground used to have its own small power stations. These needed refurb/upgrade about 20 years ago, cost £12million, so not done, bridge to National Grid instead.
No big problems since, because there are several connections, complete failure would need almost complete black out in London, but unpleasant when it happens locally
At present, when there are problems on the local commuter trains, we can fall back on 'sole possession of the way' although the drivers no longer have the brass tokens. The driver stops the train, gets out of the cab and resets the signal, which sets the signal on the next section of track to danger, so no other train will enter that section until train clears it. Not sure if they will keep the wiring that allows that in the future.
My favourite example of this is the way the PM would have launched the nuclear V-bombers towards the Soviet Union in the late 50s and early 60s: using the AA radio network!
Reminds me of some thieves who had stolen a great load of valuable electronics and other items here in Sweden, and put strong jammers in the house where they stored it.
Instead of hiding their location, this actually gave them away as it had been disturbing the GPS-coverage in this area. When the source of the jamming was found, the police was alerted and the thieves arrested.
thats profound. you bring up a good point that it will ow be fairly straight forward to map, find, and correct jammed (or low power) GPS signal.
i have long thought government postal carriers and other government vehicles should be required to stream realtime road congestion and traffic flow data.. this data could also show jammed or poor reception.
Last month in South Korea a surveillance drone lost GPS, possibly due to jamming by North Korea, and as a result crashed into its control truck, killing one engineer and injuring two pilots:
Although North Korea was intermittently jamming GPS in the
border region between 28 April and 15 May it is not known
if the jammer was operating at the time of the fatal crash.
The South has reacted angrily to the jamming, which has
interrupted navigation on more than 600 civilian flights -
and it has been likened to a form of terrorism by regional
media.
"All information recovered to date indicates that after a
loss of GPS signals to the aircraft's receivers incorrect
handling and omissions over a time period of a number of
minutes, resulted in an unfortunate chain of events that
ultimately led to the crash," the statement says.
On a historical note, if this turns out not to have been caused by GPS jamming and was purely an accident, I think this will be the first case of an accidental death caused by a drone (not counting people erroneously but intentionally targeted by drone weapons).
Should we really be surprised that people don't want to be tracked everywhere they go? Isn't my location also a matter of privacy? I wonder where you buy one of these jammers.
I saw the link ... and wouldn't waste my money since my cars don't have trackers (three are 1971 models that barely have an electric system). What I meant was that I could understand why people would want one of these devices.
Disabling the tracker in your own car is fine. However, that's not what the jammers do. They broadcast a signal that blocks GPS for everyone on a wide radius. To be able to guarantee no lock in a 10m radius means you have to interfere with GPS for at least half a km around you. It's absolutely not okay to wholesale block service to everyone near you because you want to be more private.
It is not necessary to interfere with GPS in a wider area to mask your own position. The GPS signal is very low power (below the noise floor). It does not take much effort to block it. For this reason, the in car maskers (aka jammers) will block signals over a wide area unless they are precisely engineered to stay localized. There are a lot of poorly engineered maskers out there. I study these maskers and how they affect WAAS for the FAA.
I'm not condoning this as a technique to remain "private" ... I'm simply stating that I understand why people are buying jammers and I agree that some of them should be allowed to have their privacy.
I'm not so sure about others. If you're driving a truck for a shipping company, I suspect it's their right to know where their equipment is.
What I don't understand is how a trucking company that has their unit jammed doesn't eventually figure that out and fire the driver.
[EDIT] The only thing I can think of is that the GPS is always recording, but only examined in the event of an accident. The driver can claim the unit was defective and not his fault, so there's no proof he was driving 90 in a 60 zone.
It's possible that early units weren't very reliable. If drivers started using jammers before the reliability improved than the company may just expect a high rate of failure.
The other option is that insurance companies and regulators want the GPS trackers installed, but the companies don't care as long as the deliveries get made.
There are limits on how many hours a driver is allowed to work, for safety reasons.
I can't think of anything that meets the hyperbolic claim, but I know some insurance companies have introduced driving monitors to assess how safe your driving is and adjust your premiums accordingly.
They're not blocking the signal from their own cars, but from their employer's. And possibly using it to cheat on their taxes as well.
They could probably put a stop to this by making jammer detectors and inspecting for them at weigh stations and then checking the logs on the GPS for anomalies. If the cops have a jammer detector, they can start pulling people over for having them.
If a few people lose their CDL, they should fall out of favor. These aren't very easy to hide, given that they have to broadcast to work. And if this pushes them to invent some other way to tamper with their GPS monitors, so much the better: it wouldn't cause nearly as much harm as these.
Tracking is different than just getting your own location. GPS receivers only receive data. You still need a radio or recording device to track (realtime or deferred) where you are or have been.
is a little clearer on how widespread the usage is. It estimates that there may be as few as 50 jamming incidents per day in the UK, or as many as 450.
If a jammer is driving by more than 1 of their stations or driving by a station 2 times a day, the whole thing could be explained by a few dozen of them being in use.
They have LiDAR, GPS, radars, inertial reference unit, steering wheel angle sensor and high-precision odometry (left rear wheel rotation sensor). Afaik, LiDAR/map convergence is actually used for localization.. at least it's the case for the street view car, per http://www.youtube.com/watch?v=kdPwaWATYKg&feature=plcp
I remember reading a long time ago some odd story, that one would be able to disable instruments at a relatively low flying airplane, by aiming at it a conventional parabolic satellite dish with a strong microwave component mounted on it. Anyone care to explain if this was just some urban myth or if there is any truth to that? Are there any other ways to "jamm" digital devices from a distance?
Google Street View cars have many ways of finding themselves in our world and knowing what is around them (which msftguy have kindly specified) but I guess GPS navigation is its primary instrument and without it it will be unable to drive anywhere. Device like this - http://www.jammer-store.com/gj6-all-civil-gps-signal-jammer-... - or maybe other one can easily block its GPS signal and stop it in case of emergency.
GPS isn't accurate enough to tell you what lane you're in. I'm sure it uses GPS for navigation, but it must use active sensors on the car itself for the actual driving.
You can still drive the car? Also, google has wifi methods of knowing where the car is and they still have computer vision. I think what you would want to do is jam all the frequencies that the google car receives. A better question is how could you try to make the system drive somewhere that you want to.
I thought it was refreshing to see that link, even though I didn't click on it. Seems more honest and would have saved me the detour through Google to find it myself.
At Google you'd have been given at least an array of options. If the site was transparent about any commercial interest in the vendor I'd agree with you.
The risk is not just theoretical. For example, in 2009 the Newark airport had a daily GPS failure that was finally traced to a trucker using a jammer, presumably to defeat a tracker enforcing safe driving rules. http://www.economist.com/node/18304246