10 ms·
GPS signals are surprisingly easy to disrupt
- cschmidt 13y agoThat reminds me of another Economist article about GPS jamming from 2011: http://www.economist.com/node/18304246 http://www.economist.com/node/18304246 That article was inspired by a trucker who drove by Newark Airport every day, disrupting GPS service there.
- bjcubsfan 13y agoI worked on that, but have not seen that particular article. There are actually a whole lot of them going by the Newark Airport even today.
- deleted 13y ago[deleted]
- VLM 13y ago"receivers cost £2,000 per vessel" Hmm, yes kind of like how a new GPS costs $5K, because the first .mil model did cost that much. Or all computers currently cost millions of dollars because the first ones did.
- snom380 13y agoA new GPS made for commercial, certified use (eg. for use in aviation) will cost way more that $5K. Just a software update to it might cost as much. Technology is getting cheaper, certifying it isn't. In don't know about ships, but I assume there is some form of certification for nav equipment there as well.
- D9u 13y agoI don't know about presently, but in the past the GPS transmitters had an introduced error known as "Selective Availability," the purpose of which was to deny pin-point accuracy to unauthorized devices. For a price, one could acquire the necessary hardware/software to mitigate Selective Availability in order to increase the accuracy of GPS readings, although I forget what those prices were/are.
- joosters 13y agoGPS used to be that way to give the military access to accurate positioning and provide lower accuracy to others. They can still do this selectively to whole areas of the world should they want to.
- bigiain 13y agoThis probably still mostly true. The US claim that since 2008 they've been launching GPS satellites without selective availability capabilities. That means 27 of the current working GPS satellites are older ones which do have SA which could be switched back on at any time, and 12 are newer allegedly non-SA equipped satellites.
- mikestew 13y agoSelective Availability hasn't been used for over a decade: http://www.gps.gov/systems/gps/modernization/sa/ http://www.gps.gov/systems/gps/modernization/sa/
- bigiain 13y agoI remember reading a fascinating article (which seems to elude me on Google right now) about the competitors in the 1990 BOC single handed Around the World yacht race noticing the CEP (circular error probable) on their GPS devices drop from ~100m down to ~10m or better in late July – a week or so before the Gulf War officially started. They didn't permanently switch off Selective Availability til mid 2000, but they could and did temporarily switch it off when it suited them (and, no doubt, could easily switch it back on today if they thought it worthwhile… They claim any satellites launched since 2008 haven't had SA capability, but I suspect that's only a small-ish percentage of the GPS constellation today…)
- hga 13y agoErrr, as I read it, the cost is for new eLoran receivers, intended to be an alternative backup to the Mark I eyeball if GPS flakes out for whatever reason. Not going to be widely deployed like GPS receivers, and big ships need reliability ... in fact, the only customers are those who really need this sort of thing, unless it becomes mandated.
- ThatGeoGuy 13y agoAs somebody who's primary field of study is GPS / Navigation / Positioning, I'd like to remark that survey grade receivers such as in the eLoran stations can cost much, much more than £2,000. Their price isn't so much the hardware itself, in fact, most of the receivers seen in cell phones today cost less than $1USD. However, when dealing with more accurate receivers, the receivers typically need extensive calibration and testing. I mean, it's possible to get measurements from GPS accurate to 1mm, but you need to have both a careful setup and very good knowledge about the errors associated with your receiver. So yeah, these receivers are actually quite expensive, and most of it is because the calibration on repeatability and stability of these sensors is of the utmost importance. On a secondary note, survey-grade receivers are typically not as prone to jamming as consumer-grade receivers, mostly because they can use multiple GPS frequencies / can collect over a wider bandwidth. There's a lot more to it than that, but effectively the point I'm making is that the receivers spoken of in the article are not the same as everyday GPS receivers. If you want to see how crazy the prices on these receivers can get, look no further than http://www.surveyorsmart.com/product.sc?productId=548 http://www.surveyorsmart.com/product.sc?productId=548. I doubt many surveyors would go for that particular model by Leica, as it is definitely expensive, even for survey equipment standards, but it's not unreal in terms of pricing.
- joosters 13y ago1mm?
- hga 13y agoYep, I gather that nowadays they use this type of instrument to measure e.g. how fast California is sliding into the Pacific ^_^.
- andrewcooke 13y agothis is actually easier in some ways because it's so slow you can integrate forever and so reduce noise (both "normal" noise and the added stuff, if they are still doing that).
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- bkanber 13y agoThere are different grades of GPS receivers, all licensed differently. Consumer-grade receivers have a maximum accuracy of something like 3 meters and a slow response time. There are also aviation grade and military grade receivers, which cost more (build & calibration) but also require a special license.
- ballard 13y agoI interned at Trimble in the radio group. Industrial GPS receivers could be purchased by more / less anyone, however they were built and priced for heavy-duty industrial consumption (mines, farms, ships, aircraft, etc.). The unassisted accuracy without kinematic corrections was around +- 1 m horizonal and ~10 m vertical, constantly changing as the constellation moves. This would be for a top-of-the-line 24 channel parallel receiver. WITH kinematic GPS, +- 10 mm (not a typo) horizonal and ~3 m vertical. It was so good that receivers could be installed on the left and right sides of a grader's blade that the angle and position could be known with great accuracy and precision. Kinematic means a nearby stationary reference ground base station sending updates over radio frequencies to another GPS receiver that could be in motion. This was also used to subtract SA pre-Clinton because the injected error would be the same in nearby locations.
- randomdata 13y ago$5K doesn't seem out of the question. Even commonly found used receivers can go into the thousands of dollars. Ex: http://www.agdealer.com/list/view_image.cfm?ID=401541 http://www.agdealer.com/list/view_image.cfm?ID=401541
- themstheones 13y agoI love how it's just some dude running a delivery truck inadvertently doing this. It's like something out of a movie.
- wmf 13y agoYeah, I was hoping it was the ten minutes before market close every day and some evil genius HFT operator was trying to exploit lack of time sync at the exchange.
- joosters 13y agoSame here. If they were really cunning, they could fabricate their own signal with a different timestamp. You could shut down rivals by making their computers believe that the trading day was over, or that their market feed was too slow to trust...
- nonchalance 13y agoYou could do that over very small timeframes (say, a millisecond earlier or later) but most systems don't automatically adjust times if the delta is very large
- jjwiseman 13y agoThe article mentions North Korea's frequent GPS jamming, but doesn't mention that it's suspected as a cause of the fatal drone accident last May: http://lemondronor.com/blog/index.php/2013/3/gps-loss-kicked-off-fatal-drone-crash http://lemondronor.com/blog/index.php/2013/3/gps-loss-kicked... I haven't been able to find any more recent info about the incident.
- jandrewrogers 13y agoSystems that rely on GPS are defective in their design. US military systems have never trusted GPS, since inception, because the Soviets had the ability to destroy the satellites and tinker with the RF. US military systems are inertially guided only accepting GPS corrections within the error bounds of their extraordinarily tight inertial measurements. If the GPS is outside the error bounds, it is presumed to be compromised. There is no such thing as an intrinsically GPS-guided weapon; they are always inertially guided with GPS corrections. Modern US inertial systems are similar to GPS in terms of precision so GPS is increasingly superfluous. As a consequence, the US military has never been significantly vulnerable to loss of GPS. Their systems were designed, from Soviet days, to assume that GPS could be compromised or lost since the Soviets had that ability. Knock out GPS and you still have to deal with ultra-precise solid-state optical gyros. Many commercial systems take a cheap shortcut and rely on GPS but, contrary to popular mythology, US military systems never have.
- rhodey 13y ago"The signals are weak. Mr Curry likens them to a 20-watt light bulb viewed from 12,000 miles (19,300 km)." no, just no.
- samspenc 13y agoBane?
- jessriedel 13y agoIn principle, GPS jammers are illegal, right? FCC regulations or some such?
- wmf 13y agoIn principle, you'd read the article before commenting.
- michaelwww 13y agoWhat, you didn't read it for him?
- marchra 13y agoCall the burn unit.
- DanBC 13y ago(I didn't down vote you.) This is in the UK, so it's probably OFCOM who do the regulation and prosecution. (http://stakeholders.ofcom.org.uk/enforcement/spectrum-enforcement/law http://stakeholders.ofcom.org.uk/enforcement/spectrum-enforc...) EDIT: Whoops, yes, this is mentioned in the article.
- jessriedel 13y agoWow, I'll make sure never to comment again without reading the article three times over to make sure I didn't miss a sentence...
- ChuckMcM 13y agoAs this becomes more annoying people will start watching for terrestrial GPS transmitters and start busting them.
- drivingmenuts 13y agoThey seem to be taking it awfully casually, as if it's all some minor misunderstanding between gentlemen.
- afterburner 13y agoWell it is Britain.
- eCa 13y agoShould it not be possible to track the vehicle (if it is only one) by installing GPS receivers in the area and noticing when the disruption begins and ends for each receiver? That, coupled with license plate scanners at those locations, ought to find the culprit. (And then they can launch an armed drone to take him/her out...)
- jessaustin 13y ago(Presumably the drone will use some sort of inertial guidance rather than GPS.)
- emiliobumachar 13y agoThe culprit is basically shining a very bright light (at invisible frequency) in all directions. Catching them should be even easier than your proposal. (I suppose one could program a missile to follow the light...)
- sbierwagen 13y agobasically shining a very bright light GPS satellites broadcast 500 watts from a 13dbi antenna. But they're far away. Really really far away, to the tune of 21,000km. (The Earth is about 12,000km wide.) By the time the signal makes it to the surface of the planet, the inverse square law has punched it down to -130 dBi, which is well below the thermal noise floor of room temp electronics. GPS receivers pull a useful signal out of a storm of random noise using deep information theory magic, which is vulnerable to several clever low power attacks. Even a dumb jammer doesn't need much power, though. one could program a missile to follow the light... http://en.wikipedia.org/wiki/AGM-88_HARM http://en.wikipedia.org/wiki/AGM-88_HARM "The AGM-88 High-speed Anti-Radiation Missile (HARM) is a tactical, air-to-surface missile designed to home in on electronic transmissions coming from surface-to-air radar systems."
- JonnieCache 13y ago>pull a useful signal out of a storm of random noise using deep information theory magic Any keywords I can look up as to how this is done?
- michaelwww 13y agoAs someone who was recently a delivery driver, the recent addition of GPS tracking is one of the most annoying things about a delivery job. Far worse than drug testing. Driving can be difficult and sometimes you need to park and stretch your legs. I was called into the office for this and queried about each of my stops. GPS is going to become more prevalent as people like me are highly motivated to defeat the system, especially working in teams with other drivers. Of course there are work-arounds. Park at a legit spot on an approved break and leave all your electronic devices in the vehicle and walk to where you want to be but don't want them to know about, etc... However, it is highly doubtful this was done by a delivery driver. There is no point in jamming the signal for 10 minutes. What could it accomplish? If the purpose is to take an illegal detour (going against a one way street) the company has logs of all your trips and will soon figure why you have a 10 minute gap everyday.
- nfm 13y agoI took it to mean that the 10 minute window was when the driver was driving past the LSE, where the detectors where.
- michaelwww 13y agoIt's even less likely he jams signals where ever he goes and LSE just happened to notice it. His company would be very curious why he was disappearing. They can pull him on a screen and watch when he goes in and out of range. It would happen only to him, in whatever vehicle he happens to check out that day. A driver would have to be far more clever than that. The article states "timestamps on trades made in financial institutions can be affected" There's your likely culprit; someone who for whatever reason needs to affect timestamps.
- bjcubsfan 13y agoI think it's likely a driver who is constantly jamming his GPS. I have seen this in work with the FAA. A driver will go past the airport or park and deliver something. We see a temporary GPS outage which have traced back to delivery drivers in several instances. I imagine their company assumes their GPS equipment is broken, but still lets them drive.
- teyc 13y agoThere's an Australian company who's got a land based positioning technology. It does not rely on satellites and I think it holds a lot of promises especially for airports.
- dragonwriter 13y agoLand-based, non-satellite radionavigation (particular for aircraft) is older than GPS (or satellites, or even jet engines.) (e.g., VOR, DME, TACAN, etc.)
- adestefan 13y agoDon't forget about LORAN.
- goodcanadian 13y agoI imagine they are not the only one, but are you thinking of Locata (http://locata.com/ http://locata.com/)?
- teyc 13y agoyes, thanks!
- scotty79 13y agoI guess we should migrate towards non GPS position tracking faster: http://www.darpa.mil/NewsEvents/Releases/2013/04/10.aspx http://www.darpa.mil/NewsEvents/Releases/2013/04/10.aspx
- ballard 13y agoA paper on GPS jamming countermeasures http://servv89pn0aj.sn.sourcedns.com/~gbpprorg/mil/gps4/GPS-Vulnerability-LosAlamos.pdf http://servv89pn0aj.sn.sourcedns.com/~gbpprorg/mil/gps4/GPS-... Ultimiately, the lack of MAC and encryption makes civilian GPS MITMable. (Discliaimer: I worked at Trimble.)
- ihsw 13y agoInterestingly, Google's successor to BigTable -- Spanner -- utilizes GPS clocks and atomic clocks to maintain consistency of their data across globally-distributed data stores. http://en.wikipedia.org/wiki/Spanner_(database) http://en.wikipedia.org/wiki/Spanner_(database)
- jcurbo 13y agoThis is not unique to Google, GPS is widely used as a time source for telecommunications and as an input to NTP daemons.
- sargun 13y agoAlso, Google uses accurate atomic clocks in each of their datacenters, so when their GPS connectivity gets cutoff, they can still keep time. Almost everyone does.
- leif 13y agoI didn't know GPS hammers were a thing but now I want one. Thanks, LSE.
- leif 13y agoJammers. Thanks, iPhone.
- skeoh 13y agoMake sure it is legal to own/operate one in your jurisdiction before buying any sort of jammer.
- stock_toaster 13y agoWhen all you have are GPS hammers, everything looks like... GPS nails?
- eli 13y agoIsn't GPS clock sometimes used to set up high-speed network connections? Maybe someone is jamming GPS to mess with a particular HFT application.
- rayiner 13y agoGPS signals are unsurprisingly easy to disrupt. It's a location mechanism that depends on one-way communications and triangulating an extremely precisely-timed signal between at least three far away satellites. Position fixes don't rain down like mana from heaven.
- csense 13y ago> surprisingly GPS signals come from satellites. AFAIK there are about 20-40 GPS satellites. Let's say each covers at least 1/50 of the Earth's surface area, about 500 million km^2. That's 10 million km^2 per satellite. What's the max power generation you can fit on reasonable-sized satellite that's going to be in orbit for decades? I'm guessing not more than 10 kW. So 10 kW / 10 million km^2 means you have .001 watt per km^2. GPS signals being easy to jam isn't surprising. What's surprising is that you can detect them with equipment that's small and cheap enough to fit in a cellphone!
- mikeash 13y agoWhere it really gets amazing is when you discover that the GPS signal is around 20-30dB below the noise floor. That is to say, ambient noise drowns out the signal by a factor of 100-1000. Long-term correlation manages to pull out usable information from this extremely noisy signal. An interesting consequence of this is that you don't need a very fancy receiver, hardware-wise, because your software already has to be extremely sophisticated. For example, you can use a 1-bit ADC rather than trying to be more sophisticated about exactly how strong the signal is at any given moment.
- jordanthoms 13y agoThat's crazy... I think I'll contain my frustration more now when my GPS takes a few minutes for a cold lock. It's even more crazy because with the latest GPS systems in phones, I'm able to get a fix with only a very small portion or even no sky visible.
- mikeash 13y agoInterestingly, the cold lock acquisition time is usually gated by the time required to download the almanac from the satellites, rather than acquiring the actual GPS signal. The almanac (which is the stuff that basically tells you where the satellites are, so you can figure out where you are based on that) gets sent on a side channel at a very slow rate, something like 50bps, such that it takes about 30 seconds before you have all the data, and any interruption can mean it takes multiples of that. The main advantage cell phones have is the fact that they can download that data from the cell network rather than waiting for it to dribble in from the satellites directly. The ability for GPS to (sometimes) work indoors these days is indeed pretty crazy. The signals are already incredibly weak, and you'd think having a roof and walls and pipes and wiring in the way would make it impossible to read them.
- bobdvb 13y agoMany many years ago I was a specialist in satellites for a major European broadcasting company. We had a problem with couriers who used radar speed trap jamming devices. They had really noisy oscillators which leaked huge quantities of out of band noise into the dished which were located near the courier drop off point. We initially used an expensive spectrum analyser attached to a spare LNB (pointed at the parking area) but that needed you to notice the noise. So I used a USB enabled RF power meter interfaced to Excel (so sue me, it was a rush job and we weren't equipped for development). A script ran which fetched values, when there was a spike in received power it played an alarm and flashed the screen. The next step was to ask security to hold anyone in the carpark while a large angry engineer went to give the courier a piece of his mind. It worked, courier companies were informed, people were shouted at and I believe it stopped. There are probably better ways of doing this, but it was effective and built from spare parts.