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Anatomy of a "signal generator":
Generally, "jammers" — which are also commonly called signal blockers, GPS jammers, cell phone jammers, wifi jammers, etc. are radio frequency transmitters that are designed to block, jam, or otherwise interfere with radio communications.
A jammer can block radio communications on devices that operates on a given radio frequencies within its range (i.e., within a certain distance of the jammer) by emitting a noise radio carrier. A GPS jammer generates a 1575.42 Mhz interference to prevent your GPS unit from receiving correct positioning signals. The GPS jammer is typically a small, self-contained, battery powered and transmit signal over a small radius. Though illegal to use, these low-tech devices can be bought on the internet for as little as $25. Since they can block devices that record a vehicle's movements, they're popular with truck drivers who don't want an electronic spy in their cabs. They can also block GPS-based road tolls that are levied via an on-board receiver. GPS jamming technology will also disable autopilot in drones to protect individuals' privacy.
In the US federal law prohibits the sale or use of a transmitter (e.g., a jammer) designed to block, jam, or interfere with wireless communications. For this reason some jammer retailers now label jammers as "signal generator kit" so it will just slip through customs and them is to purchaser sole responsibility for ensuring that the operation complies with the applicable laws. One of these "GPS signal generator kit" is the Dealextreme QH-1 Professional GPS Signal Generator Module (It seems that the QH-1 GPS jammer ran out of stock and will not be manufactured anymore, but you can still find HJ-3A GPS and cell phone jammer.). I've always wondered what's inside these jammers, given their cost, so i purchased one "signal generator module" and put under test with RF laboratory equiment, disassembled and photographed them for all to enjoy.
But is it cheaper than tinfoil?
[Ed note: typos and grammatical errors copied from source document, intact. Also note that it is illegal to operate one of these jammers in the US.]
(Score: 2) by Virindi on Saturday December 02 2017, @07:13PM
It uses a 555. Classic.
(Score: 5, Interesting) by frojack on Saturday December 02 2017, @07:38PM (5 children)
I've actually encountered GPS jammers on the road twice. Once while driving in Arizona, I pulled up near an 18 wheeler and suddenly my GPS Said "Recalculating ... Recalculating", and showed me in Iowa. It was horribly hozed until I was half a mile ahead of the truck.
What would a driver-less vehicle do in this case? Pull over and stop? Sure the cameras would probably operate to keep it on the road, but the computer might be so busy trying to find the exact road in Iowa that matches what the cameras see that they are effectively DOSed.
Jammers often don't indicate NO Signal, they often mess with or bias the signal, putting you a thousand miles from where you actually are. That's worse than no signal at all.
Most enthusiast drones are flown line of sight. However, even inexpensive drones can be programmed to reject controller input, and return and land at their take-off point when their battery gets low enough that return is advised. With either no GPS or false GPS induced by jammers, there are going to be a bunch of lost toys, and maybe lots full of trapped [techcrunch.com] driver-less cars.
Related - But different: Random Kansas Farmhouse [splinternews.com] just happened to be a default location in at least one piece of software, and it brought a steady rain of cops.
No, you are mistaken. I've always had this sig.
(Score: 3, Interesting) by Anonymous Coward on Saturday December 02 2017, @07:51PM (1 child)
There is usually a number on the side of the truck and on the trailer. Both DOT and phone #s. You could have called it in? I am *very* sure their terminal manager would have been *very* *very* *very* interested in that.
The only reason for a truck driver to short out the GPS is to cheat the system. I have heard all the excuses. Every last one, cheating the system in some way. Either in time, miles, not being where they should, something.
Most truck drivers do not know but we also use cell tower triangulation to find them. It is a bit more tricky to do and kind of expensive so we usually just do it with quarterly audits. When your gps says iowa (where you are supposed to be) and your cell records all say arizona (where you are) you may just be up to something.
(Score: 1, Insightful) by Anonymous Coward on Sunday December 03 2017, @01:27AM
Yes, and this is why people should not use cellphones; they are necessarily tracking devices.
(Score: 2, Insightful) by Anonymous Coward on Saturday December 02 2017, @08:21PM (2 children)
With respect to navigation systems (either driving aids or for autonomous navigation systems) it would be trivial to protect against this kind of interference using old tech and a bit of clever programming. First off the tech: inertial navigation systems have been around since World War II. While they aren't as accurate as modern day GPS, they are sufficiently accurate to prevent extremely large errors from cropping up (like being suddenly transported thousands of miles away) and to keep roughly on track for extended periods without GPS. Clever programming also makes this issue moot. We know that it is physically impossible for any vehicle to move thousands of miles in an instant. When this occurs the system should naturally ignore this spurious result and stick to the old data until a more reliable update is made. Combining either of these with modern sensor technology should protect against this and other forms of tampering. I can easily see future navigation systems, especially those used in autonomous transportation systems, including topographic data with resolution sufficient for a vehicle to know its location by a simple laser and optical scan of the area, comparing against its internal maps.
Also worth mentioning is that the british navy is working on a navigational system for their submarine fleet that uses the earth's magnetic field to locate itself. Last I read the device was about the size of a shoebox but that will be reduced eventually.
(Score: 0) by Anonymous Coward on Saturday December 02 2017, @08:39PM
Yes, of course inertial nav and other nav systems can fill in for missing GPS signals. Sometimes called "sensor fusion" there are test systems that combine GPS and inertial nav being used at automotive proving grounds, with centimeter accuracy.
But all this costs time and money to develop, so unless this is mandated for certain applications my guess is that it isn't happening anytime soon.
(Score: 4, Insightful) by frojack on Saturday December 02 2017, @08:50PM
Your average Passenger Car GPS is not funded by the British Navy.
These COTS GPS nav devices already know about bad signal area, mountains, tunnels, tall building canyon streets, etc and drop into some form of dead reckoning mode, and if they have a "can-bus" tie in, use vehicle speed as an input. They are already programmed not to panic in these areas.
That's entirely a different thing than suddenly, in the middle of a desert freeway, having only their built in magnetic compass to go by, seeing signals indicating location is 1000 mile away from where it was seconds ago, and having that new signal persist for some minutes.
Seems wrong headed to start building heroic measures into every car GPS beyond simply indicating to the driver that GPS is not available.
On the other hand, these jammers are not hard to detect, and that could be built into the freeway signage overheads. If we are going to have thousands of self driving cars and trucks out there it might be worth getting out ahead of this problem by at least installing some detectors to measure the size of the problem.
No, you are mistaken. I've always had this sig.
(Score: 3, Informative) by frojack on Saturday December 02 2017, @07:45PM
By yummy snacks. Eat Snacks. Put tracker in bag. [npr.org] Jam tracker. Win Win.
No, you are mistaken. I've always had this sig.
(Score: 2) by opinionated_science on Saturday December 02 2017, @07:50PM (11 children)
any idea of how good the Android/iPhone accelerometers are?
Curious to know if they can offset the effect of jammers...
(Score: 1, Interesting) by Anonymous Coward on Saturday December 02 2017, @07:54PM (10 children)
The J bus knows. It controls the truck. It can tell you are in drive and the engine is going and the odometer is increasing. That gets 99% of movement. You could probably follow the angle of the wheels from steering and actually trace it back out on a map. Would be tricky to get right but it should work.
(Score: 3, Interesting) by frojack on Saturday December 02 2017, @08:27PM (7 children)
Depends on who's truck it is. Lots of time all you actually have access to is the trailer or your merchandise in the trailer.
Besides, building a INS seems the hard way.
There are plenty of AM and FM radio and Digital TV towers scattered all over the country that are fairly easy to RDF or triangulate with nothing more than signal strength. Chipsets are already available for all of these, and you need only record relative strengths every X minutes for post trip analysis, or to phone home with a cheap cell modem a few time a day.
No, you are mistaken. I've always had this sig.
(Score: 2) by KilroySmith on Saturday December 02 2017, @09:37PM (6 children)
So you're suggesting that the solution to someone jamming GPS RF signals...is to listen to cellphone RF signals?
And when the jammers become GPS+Cellphone jammers, listen in on TV signals?
And when the jammers become GPS+Cellphone+TV jammers, listen in on AM signals?
When does it end?
(Score: 1) by Ethanol-fueled on Sunday December 03 2017, @01:20AM
Where does it end? Either directly integrated in the road, or better, my solution -- a hybrid rail/car system which combines the best of both worlds of safety, privacy and independence, and uniformity of traffic flow. As others have mentioned ad-nauseum, some kind of dual-or triple-factor system should be used with ultimate accuracy. I would suggest rather than an INS a 3-beam doppler sensor aimed down the bottom of the vehicle directly at the road. The main advantage of this would be extreme accuracy and granularity of measuring the exact arc and direction of turns as well as velocity on all surfaces. It would not be susceptible to jamming and ability to compensate for uneven height of surfaces (up down hills, even while turning, speed-bumps etc) in such technology has been well-understood for decades.
Of course, if it is too accurate (as it should be) the gubmint will get involved because Muh Terrorism and cripple it to the point of being useless or ITAR-regulate it. Not that Europe would want it anyway, they seem to be having a lot of truck-related problems lately.
(Score: 2) by VLM on Sunday December 03 2017, @02:33AM (3 children)
Use aircraft VOR navigation and ILS beacons and when you jam them the FAA with F-22s will show up.
(Score: 1) by Ethanol-fueled on Sunday December 03 2017, @04:27AM (2 children)
I always like what you have to say, but haphazardly throwing around a bunch of military terminology in this case makes you look like a hammer treating every solution as a nail.
Our situation needs to be a little more intimate to the problem at hand. We're way passed TACAN on the ground, we just don't know it yet. I switched majors because chemistry nomenclature was inconsistent. I was in Chem 101 when I learned that the only way forward was to memorize through brute force the nomenclature of mono and polyatomic ions. -ates and -ites are -2 or -3 depending, as one example.
So I decided that I should go back to my exact science of electronics. But then I barfed, because it has the same problem: microwaves have longer wavelengths than millimeter waves. You would think that microwaves would have shorter wavelengths than millimeter waves, but you would be wrong. Microwaves go up to 30 GHz, even though micro is smaller than milli, but millimeter waves are from 30 GHz up to the hundreds of GHz.
(Score: 2) by Aiwendil on Sunday December 03 2017, @12:23PM
So - you are annoyed at that they used the word "micro" in the sense small (which is what the word actually means) and decided to use "milli-" in the sense "1 to 10mm long"?
I'm curious: when armed with ca 1930s knowledge what name would you have chosed for waves smaller than what is currently in practice to use? [parvwave? paulwave? petitwave?]) (if anything - you should be annoyed that it stops at the mm band and not just keeps going ad infinition (maybe renaming the "microwave" band to the centiwave band))
Personally I'm annoyed at that "small" (micro) is used as a word for something specific to begin with - so in part I share your annoyance - but it could have been worse, they could have called them "dwarf-waves" (nano-)
(Score: 2) by VLM on Monday December 04 2017, @01:03PM
You're lucky you got out before they inflicted the WWII era secret radar band designation on you and today people still talk about S band vs X band which is about 5 ghz higher and the other ten or so WWII radar bands. That designation system is really annoying. Even outside radar / ECM, like people call big dish satellite TV "C band" vs the "K band".
My favorite inconsistent metric problem is I've met normies who kinda understand centimeters from being taught CGS at school and then they take the "its all about the 100x" to everything and its possible to get into interesting arguments with people about ping times where they'll insist a 100 ms ping time is 1 second because 100 centimeters is 1 meter.
(Score: 2) by frojack on Sunday December 03 2017, @03:00AM
I'm suggesting to the AC who recommended building an initial navigation system into the trucks j bus, that his method wouldn't work, or would be too costly, whereas something the size of a cell phone can fulfill the tracking needs of major shippers sending valuable cargo over the highways using contract truckers.
This would have been clear if you had bothered to follow the thread instead of rushing in to but words in my mouth.
No, you are mistaken. I've always had this sig.
(Score: 4, Interesting) by edIII on Saturday December 02 2017, @10:06PM (1 child)
There used to be a system that did rely *only* on the movement of the wheels, angle of the tires, etc. I was in this guys car in Los Angeles back in 1988-1990 (IIRC), and he showed me his guidance system. It did indeed show where we were, and our next steps on an amber screen mounted on the dash. Overtime it lost its accuracy, but it could keep it going for about days use. He told me that he needed to calibrate it almost daily. Started at the very beginning of his street, getting out of the car to be sure. You drove about a half a mile and then input your location again. After that the system was calibrated and knew where your vehicle was.
It was really cool at the time, but even he acknowledged it was too expensive and impractical. Just bought it to geek out. I'm fairly certain they only had accurate maps for Los Angeles and a few other cities. He never said it worked well out of the city. That, and it was amazing you could retrofit a car with that much computing power back then.
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 2) by VLM on Sunday December 03 2017, @02:32AM
Navicom?
http://7car.tw/articles/read/12512 [7car.tw]
The pictures don't look like what I remember.
In the 80s/90s I was interested in TSD rallys for the novelty and sheer technological challenge and curta calculators and all that stuff, then cheap GPS rolls out and the sport turns into a mode on the GPS, essentially. But, before GPS, there was COOL stuff out there.
(Score: 3, Insightful) by Snotnose on Sunday December 03 2017, @01:42AM (3 children)
would keep the last known co-ordinates when things went sideways. You moved 500 miles in the last 30 seconds? Yeah, we'll just toss that data point.
Too bad the GPS makers rely on H1-B engineers, who are more interested in meeting deadlines than writing reliable code.
When the dust settled America realized it was saved by a porn star.
(Score: 0) by Anonymous Coward on Sunday December 03 2017, @02:21AM (2 children)
Maybe the earlier data was spoofed and the new data is valid. The computer can't tell, and it's funny that you think the main issue is the visa status of the programmers.
(Score: 1, Insightful) by Anonymous Coward on Sunday December 03 2017, @02:48PM
"Maybe the earlier data was spoofed and the new data is valid. The computer can't tell, and it's funny that you think the main issue is the visa status of the programmers."
If you get a position via GPS that is 1000 miles away from your last position you received 1 second ago, what do you think is more likely:
1) That the object actually moved 1000 miles in one second
2) the GPS data, while valid, is incorrect, and should be tossed.
Only an idiot of a programmer would think "Oh yeah, that is obviously valid" (unless of course, you are working on something actually capable of jumping 1000 miles in a second, in which case either you are most likely working in Area 51)
(Score: 0) by Anonymous Coward on Tuesday December 05 2017, @04:17AM
yeah, he thinks software engineering qualifies one to become an authority on instrumentation engineering. Only an idiot instrumentation engineer would think he should override the data his instruments are providing because "it doesn't seem right"... the fool can't even recognize that a consumer GPS device is a precision instrument whose job is to translate time signals into a global position.. not to differentiate between real and fake satellite signals.
And notice that he doesn't provide a solution to the problem - because there isn't one - if the signal shows that position shifted 500 miles in 30 seconds, then what does he think the GPS device should show? a calculated position based on previous heading and speed? What if his vehicle went around a curve or slowed or stopped? And how long should it continue showing data that is divergent from the signal being received? There are many other scenarios where this clown's "logic" would divorce what is displayed on the screen from what is being received by the instrumentation. Which is a recipe for disaster.
Luckily for us those "h1-b" programmers actually know their job, what their devices need to do and are capable of. Unlike this moron who lacks even the basic ability to differentiate between a hammer (GPS) and a screwdriver (fake satellite signal detector or reality detector aka actual position detector) and thinks they are both the same tool! And he calls the gps engineers brain dead...
(Score: 2) by Flyingmoose on Sunday December 03 2017, @04:06AM (1 child)
Would it be legal to operate one in a RF-proof room or enclosure for testing purposes? The college I went to had such a room for testing student RF projects.
(Score: 0) by Anonymous Coward on Sunday December 03 2017, @05:22PM
Yes, but if you were testing how well it did at messing with GPS, the room would kill the GPS signal first.