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Bypassing US GPS Limits For Active Guided Rockets

timothy posted 1 year,21 days | from the use-for-good-not-for-evil dept.

Hardware 126

Kristian von Bengtson writes with a link to a short guest post at Wired with an explanation of how his amateur rocket organization Copenhagen Suborbitals managed to obtain GPS receivers without U.S. military limits for getting accurate GPS information at altitude. Mostly, the answer is in recent relaxations of the rules themselves, but it was apparently still challenging to obtain non-limited GPS hardware. "I expect they only got the OK to create this software modification for us," von Bengston writes, "since we are clearly a peaceful organization with not sinister objectives – and also in a very limited number of units. Basically removing the limits is a matter of getting into the hardware changing the code or get the manufacturers to do it. Needless to say, diplomacy and trust is the key to unlock this."

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Huh (1)

Anonymous Coward | 1 year,21 days | (#45002215)

Honestly I am a little surprised no one on Alibaba sells unlocked gps. There are enough tech manufacturers outside the US that you think someone would sell it.

Re:Huh (2)

i kan reed (749298) | 1 year,21 days | (#45002263)

Cruise missiles go a long way in expressing customer dissatisfaction, I guess.

Re:Huh (5, Funny)

Thanshin (1188877) | 1 year,21 days | (#45002499)

Cruise missiles go a long way in expressing customer dissatisfaction, I guess.

"ICBM. We go the extra mile so you can reach out to your customers."

Re:Huh (4, Interesting)

interkin3tic (1469267) | 1 year,21 days | (#45002395)

Demand is pretty low I guess. When I was playing ingress and my GPS signal was bouncing away from what I was trying to capture, I sometimes feverishly thought "I'm going to look up how to get MILITARY GRADE GPS on my phone! Then I'll be unstoppable!" But even if someone offered a phone with that, and even if it did improve ingress, and even if I did still play, I'd only be willing to pay an extra $30 for it. That's the only use I'd have for unlocked GPS, and I don't even currently have it. Non-nerds don't even realize the GPS we civilians use is limited.

For that matter, I was talking to a friend who is in the marines and who... er... does stuff with maps for driving humvees. She didn't know if she used the military GPS, she didn't even know her iphone GPS was limited.

What seems strange to me is that they do limit GPS in the first place. Seems like anything where military level GPS could be used dangerously, it's not that high of a barrier. You don't need super accurate GPS to make a car bomb, and if you're competent to make your own attack drone, you probably know how to bypass the restrictions.

(Hi, NSA. Congrats on keeping your jobs when government workers who DON'T shit on the constitution aren't being paid.)

Re: Huh (5, Informative)

mpoulton (689851) | 1 year,21 days | (#45002683)

The limitations at issue are not accuracy limits. Nowadays there are no real differences in accuracy between military and civilian GPS, since selective availability was turned off years ago. The problem is that civilian GPS firmware prohibits the device from giving a fix if it is above a certain altitude (around 60,000 feet) and moving faster that about mach 1. This makes it useless for midcourse guidance of a rocket, which is the point.

Re: Huh (1)

Anonymous Coward | 1 year,21 days | (#45002887)

"The problem is that civilian GPS firmware prohibits the device from giving a fix if it is above a certain altitude (around 60,000 feet) and moving faster that about mach 1. This makes it useless for midcourse guidance of a rocket, which is the point."

I see. So a V1 would be Ok to use, good to know.

Re: Huh (0)

Anonymous Coward | 1 year,21 days | (#45003357)

Or an X-15 Cruize Basselope

Re: Huh (1)

Dexter Herbivore (1322345) | 1 year,21 days | (#45003453)

A V1, or a Scud.

Re: Huh (5, Informative)

Andy Dodd (701) | 1 year,21 days | (#45002955)

Not entirely true. The P/Y code still offers improved accuracy compared to even a non-degraded C/A code due to it being transmitted at 10x the rate of the C/A code. It also allows for dual-frequency operation, permitting ionospheric delay to be corrected for. (There are tricks to using the P/Y code to obtain iono delay even without the decryption keys by cross-correlating the signals on each frequency, but these require a LOT of data collection and processing and I think the receiver has to be stationary.)

That said, modern civilian receivers do such a good job of processing the C/A code that they come close to matching many military receivers which are processing the P/Y code with far older hardware/software algorithms. Systems like WAAS can compensate for a large amount of ionospheric delay even without dual-frequency operation.

Upcoming GPS satellites will permit civilian dual-frequency operation.

Re: Huh (0)

Anonymous Coward | 1 year,21 days | (#45003893)

There are tricks to using the P/Y code to obtain iono delay even without the decryption keys by cross-correlating the signals on each frequency, but these require a LOT of data collection and processing and I think the receiver has to be stationary.

Actually, you can get civilian dual-frequency GNSS/GPS-receivers that are both mobile, lightweight and have very low power consumption. Take for example Septentrio's AsteRx-m OEM board: you get dual-frequency GPS+GLONASS, RTK, 6 millimeters horizontal position accuracy, a power consumption of only 0.49 Watts and a weight of 47 grams!

Re: Huh (4, Informative)

Bob the Super Hamste (1152367) | 1 year,21 days | (#45004167)

Check out RTK [wikipedia.org] systems using the L2 carrier to figure out the ionospheric error. Yes you do need a stationary unit and also a mobile unit. If you want real time corrections you need a wireless link between them to transmit the corrections over and it becomes harder to get rid of the off by 1 error that is often prevalent. More popular is to have a base station that is operational recording raw pseudo range and carrier phase data at a well known position (survey bench mark or from a long initial self survey) and a roving unit also collecting the pseudo range and carrier phase data. Once your surveying is done the data is post processed to provide highly accurate results. The problems with single reverence station RTK solutions like that is that you are limited to a radius of about 10mi (might be km) before the accuracy starts falling off so a better solution is having a CORS network [state.mn.us] with the ability to create virtual reference stations from "near by" reference stations.

Re: Huh (0)

Anonymous Coward | 1 year,21 days | (#45004771)

Oh look, a techno-hipster who read about RTK on kickstarter a few weeks ago and now is an expert.

Re: Huh (3, Insightful)

interkin3tic (1469267) | 1 year,21 days | (#45003075)

Ah, so I'm basically wrong. I'm trying to make a joke about inaccurate GPS and making uninformed posts to slashdot, but I've got nothing. So I'm just going to say "Good to know, thank you!"

Re: Huh (1)

mordenkhai (1167617) | 1 year,21 days | (#45004411)

Nothing to see here.... Undoing accidental mismod.

Re: Huh (2)

BitterOak (537666) | 1 year,21 days | (#45003579)

The problem is that civilian GPS firmware prohibits the device from giving a fix if it is above a certain altitude (around 60,000 feet) and moving faster that about mach 1. This makes it useless for midcourse guidance of a rocket, which is the point.

Is someone with the technical abilities to build a guided missile really going to be deterred by the fact that off the shelf civilian GPS firmware is crippled in this way? The specifications for the GPS system are publicly available and many manufacturers have successfully used them to build GPS receivers, so it can't be rocket science (pun intended). And even if one were to use off the shelf GPS components, how hard would it be to modify the firmware? Firmware is just software stored in some type of read only or flash memory. Would it be that hard to download, inspect and modify it? It seems to me it would be about as hard as removing copy protection from a game.

Re: Huh (1)

jacknifetoaswan (2618987) | 1 year,21 days | (#45003645)

It's more likely that there are some sort of cryto-keys required to access the other signal bases. Without those keys, you're SOL, even if you could reverse engineer the software.

Re: Huh (0)

Anonymous Coward | 1 year,21 days | (#45004305)

Um, no. You are still receiving the same signals regardless of your speed/altitude. The receiver's firmware decides whether it is ok to report the data or not.

Re: Huh (2)

budgenator (254554) | 1 year,21 days | (#45005127)

The keys would have to be stored in the firmware somewhere, just a matter of finding and recognising them.

Re: Huh (5, Informative)

mpoulton (689851) | 1 year,21 days | (#45003769)

Is someone with the technical abilities to build a guided missile really going to be deterred by the fact that off the shelf civilian GPS firmware is crippled in this way? The specifications for the GPS system are publicly available and many manufacturers have successfully used them to build GPS receivers, so it can't be rocket science (pun intended). And even if one were to use off the shelf GPS components, how hard would it be to modify the firmware? Firmware is just software stored in some type of read only or flash memory. Would it be that hard to download, inspect and modify it? It seems to me it would be about as hard as removing copy protection from a game.

Yes, it is a substantial deterrent. The limitations are imposed in the lowest-level parts of the GPS receiver, the first stage of data processing at which it is technically feasible to infer speed and altitude. The hardware that runs this code is highly specialized - it's a mixed analog/digital RF ASIC that is designed in hardware to run that specific code, including the limitation. There is little distinction between hardware and firmware at that point, and it is likely that the code responsible for the limitation is not programmable/reprogrammable at all. The sophistication needed to build a rudimentary short-range guided missile is surprisingly basic, and many hobbyists (or terroristically-inclined groups) could do it without too much difficulty, on a five-figure or low-six-figure budget. The GPS limitation significantly hinders the on-target accuracy that could be achieved, since the high speed terminal phase of the flight is where excellent guidance in an absolute reference frame is most important. The sophistication needed to build or microscopically alter a GPS receiver without the limitation is significantly greater (and in an entirely different technical field) than what is needed to build a missile that would benefit from that GPS guidance.

Re: Huh (0)

Anonymous Coward | 1 year,21 days | (#45004379)

and it is likely that the code responsible for the limitation is not programmable/reprogrammable at all

Did you not read the summary? It most certainly is programmable at least once because the manufacturer was able to provide small quantities of a version of the device without the limits.

And at least some receivers do use flash to store the firmware.

Re: Huh (1)

Pinky's Brain (1158667) | 1 year,21 days | (#45005315)

Ever looked how many DIY GPS receivers are out there? On a six figure budget it wouldn't be much trouble getting something made.

Re: Huh (1)

X0563511 (793323) | 1 year,21 days | (#45003867)

Accuracy isn't even the Big Deal with it, it's authentication.

Re: Huh (2)

Bob the Super Hamste (1152367) | 1 year,21 days | (#45004007)

There still are differences in the accuracy between military and civilian gps but it isn't the 10s of meters that was in place with selective availability. The military gps has access to the unlocked L2 channel while the civilian one still just has access to the L1 data. By having both the L1 and unencrypted L2 data it is possible to do RTK like corrections within a single device instead of having 2 devices with one at a well known location sending corrections to a mobile one. For most people a +-3 meter accuracy is fine (WAAS gives you this) but it is possible to get down to +-2 cm accuracy (ideal case) with RTK or military GPS.

Re:Huh (2)

Kjella (173770) | 1 year,21 days | (#45002685)

What seems strange to me is that they do limit GPS in the first place. Seems like anything where military level GPS could be used dangerously, it's not that high of a barrier. You don't need super accurate GPS to make a car bomb, and if you're competent to make your own attack drone, you probably know how to bypass the restrictions.

Well we're mixing apples and oranges here, there is a civilian signal and a military signal and what this article is talking about is removing some software limitations on where and when a civilian GPS unit will work, in short if you tried to use one aboard an airplane it'd blank out, not because it couldn't get signal but because the reciever is too high and going too fast for what is permitted. They still can't decrypt the military signal which gives them higher accuracy and timing signals to make precision strikes with high speed missiles.

Re:Huh (1)

NatasRevol (731260) | 1 year,21 days | (#45003205)

Do you really need precision strikes for high speed missiles?

I found my wife's phone that she dropped in a park by using Find Your iPhone app.

That's probably close enough for any missile.

Re:Huh (0)

KingMotley (944240) | 1 year,21 days | (#45003355)

But it's not accurate enough for sharks with lasers heads.

Re:Huh (1)

ShanghaiBill (739463) | 1 year,21 days | (#45003681)

Do you really need precision strikes for high speed missiles?

Civilian GPS is not "low precision" at high altitude/speed, it stops working completely. If you are above 60,000 feet OR going faster than 999 knots, then it is supposed to completely shutdown.

Re:Huh (2)

X0563511 (793323) | 1 year,21 days | (#45003929)

If you can keep the GPS online until 60,000 and then turn it back on when you drop below, that's probably enough for the job. On the way up it establishes your ballistic arc, and on the way down you can correct for peterbances that occurred. Basic INS stuff could deal with the between.

Re:Huh (2)

Bob the Super Hamste (1152367) | 1 year,21 days | (#45004237)

Actually it is suppose to be an AND not an OR but most manufactures of civilian stuff find it is easier to do an OR since how often do regular people travel above 60,000 feet or travel above 1000 knots. In the hobbyist market for GPS modules it is a selling point that they operate with the AND instead of the OR functionality.

Re:Huh (1)

budgenator (254554) | 1 year,21 days | (#45005323)

Depends on the traget and what your shooting at it, trying to detonate a 50 Kt MIRV within 300 m of a reinforced missile silo at 12,000MPH is pretty tough, an 81mm mortar round within 35 m of a crowd in a park is pretty easy.

Re:Huh (1)

X0563511 (793323) | 1 year,21 days | (#45003915)

Not very many passenger flights extend beyond 60,000' and/or 1000 knots...

Re:Huh (1)

enrevanche (953125) | 1 year,21 days | (#45002769)

What seems strange to me is that they do limit GPS in the first place.

So that they can charge 10 or more times more for GPS receivers sold to the military.

Re:Huh (1)

Gareth Iwan Fairclough (2831535) | 1 year,21 days | (#45003247)

They already do that when they sell to the military :P

Re:Huh (1)

enrevanche (953125) | 1 year,21 days | (#45005777)

Ok, then 100 times more for the high-res config option enabled and a snazy camouflage case.

Re:Huh (4, Interesting)

Sarten-X (1102295) | 1 year,21 days | (#45002907)

if you're competent to make your own attack drone, you probably know how to bypass the restrictions.

Well, yes... but it's one more thing to screw up, and it takes time, and you need someone who knows how to reprogram a receiver's firmware rather than just an Arduino, RPi, or other DIY autopilot.

Amazingly, the US government does actually understand that perfect security is impossible. Rather, the modern security strategy is centered around making enemy attacks more difficult, ideally requiring so much planning and expertise that they can be noticed and stopped before coming to fruition. As you've seen, most folks don't know that GPS is artificially limited, and most normal applications don't need the high precision of an unlimited receiver. When someone starts asking around on forums or posting classified ads looking for GPS firmware experts, suspicions are rightfully raised.

Of course, with more suspicion comes the need to eliminate such suspicion. If you're claiming to need unrestricted GPS for rocketry, this probably isn't your first rocket. There's likely records of supply purchases, perhaps travel to launch sites, and probably even phone records of you calling other rocketry experts. If only there was some big searchable database of exculpatory evidence, to help quickly separate the valid suspicions from the false positives...

NSA... shit on the constitution...

What seems strange to me is that we're mad at the NSA for invading our privacy, when we really should be mad at them for having poor access control. In my opinion, the NSA's databases should be kept operational, but with a PR campaign and better operational security. Database queries must be associated with an ongoing investigation, which could be started with as little as an anonymous tip, and must end either with escalation (to the judicial branch) or dismissal accompanied by a letter to the target disclosing the inquiry and its nature. Records should also be subject to subpoenas, but their contents must be reviewed by the judge prior to inclusion in any trial.

The NSA has built the ability to find evidence on an unprecedented scale. We should not fear such an ability, but rather we should be demanding that such power directly and visibly serves the people.

Re:Huh (5, Interesting)

TheCarp (96830) | 1 year,21 days | (#45003517)

> The NSA has built the ability to find evidence on an unprecedented scale. We should not fear such
> an ability, but rather we should be demanding that such power directly and visibly serves the people.

I am not really sure I agree. A lot of progress socially and morally has come from law breakers. What goes on behind closed doors is a rather new area to be moving into and reveals many things that we may or may not have known was going on before...and I am not so sure thats unmitigated good.

If these abilities existed 30 years ago, where would the gay rights movement be today? Making it easier to gain "evidence" could have been absolutely terrible then. Had they existed 50 years ago, would the civil rights movement been able to organize?

What makes us think that today we have it all right and from this point forward knowing about everything will just be good? Frankly, I doubt a society that can enforce all of its laws all the time is capable of progress.

Re:Huh (1)

Sarten-X (1102295) | 1 year,21 days | (#45004969)

A lot of progress socially and morally has come from law breakers.

As has a lot of regression and resistance to change.

When an activist intentionally breaks a law as an act of civil disobedience, usually the goal is to be caught. During the ensuing trial, the activist's chosen issue is discussed in the media at length. Privacy surrounding the act is undesirable, and the records of the activist's actions leading up to the event would be subject to the judge's review before being made public. As a matter of course, anyone accused of a crime could be protected from inquiries without a warrant, to prevent overzealous prosecutors from going after the activist's associates.

As for where gay rights would be today, I'd suspect about the same. Civil rights, on the other hand, wouldn't have had to deal with the militant violence of the Black Panthers and related groups, instead focusing on King's speeches and his message of nonviolence. The movement could have been dominated by calls for improvement, rather than calls for revolution. Perhaps today, we'd have government that responds to peoples' requests, rather than treating everyone as an adversary.

"What goes on behind closed doors" is already known to the participants. For a government that ostensibly follows the will of the people, protecting those participants from injustice, regardless of their opinions, is its duty. Being inside those closed doors and aware of everything going on, with strong operational security, helps fulfill that duty. Again, though, the information gathered should be kept secure unless it's needed - and only then should it be used on a limited basis, and its use should be known to those affected.

Re:Huh (1)

TheCarp (96830) | 1 year,21 days | (#45005413)

> When an activist intentionally breaks a law as an act of civil disobedience,
> usually the goal is to be caught

So was every gay person who engaged in relationships with other gay people an activist? Or were they all criminal scum because they didn't intend to get caught?

> As a matter of course, anyone accused of a crime could be protected from inquiries
> without a warrant, to prevent overzealous prosecutors from going after the activist's associates.

As a matter of course, we already can see the results of this. We already have drug cases where police have received secret tips and then manufactured a false chain of events to justify an arrest and hide the real source of information. This kind of protection after the fact is necessary, but its hardly sufficient: http://www.reuters.com/article/2013/08/05/us-dea-sod-idUSBRE97409R20130805 [reuters.com]

> For a government that ostensibly follows the will of the people, protecting those participants from
> injustice, regardless of their opinions, is its duty. Being inside those closed doors and aware of
> everything going on, with strong operational security, helps fulfill that duty

follows the will of the people WITHIN LIMITS. It doesn't matter if the will of the people is to silence speech, it is not the governments job to enforce that.

Those limits specifically include protections against search. They specifically were aimed at preserving personal privacy behind closed doors. I cannot believe that the people who wrote the 4th and 5th amendments would have envisioned such a program as falling within their powers to implement.

Re:Huh (2)

WaffleMonster (969671) | 1 year,21 days | (#45003021)

What seems strange to me is that they do limit GPS in the first place. Seems like anything where military level GPS could be used dangerously, it's not that high of a barrier. You don't need super accurate GPS to make a car bomb, and if you're competent to make your own attack drone, you probably know how to bypass the restrictions.

It is just an export limit. We can have/use the technology here in the US as long as it stays here. Relevant ITAR restrictions are:

"Designed for encryption or decryption (e.g., Y-Code) of GPS precise positioning service (PPS) signals;"

  "Designed for producing navigation results above 60,000 feet altitude and at 1,000 knots velocity or greater;"

There is not really a "soft" restriction on accuracy because none of us possess the decryption key for military carrier. Limits on accuracy is mostly caused by "ionospheric delay" from signals traveling thru charged upper atmosphere. Now that other GPS constellations are in operation it is possible to construct a receiver to concurrently examine timing/phase of multiple carrier frequencies to get an active handle on ionospheric delay and significantly improve accuracy. New civilian signals being added to GPS will also provide improved accuracy.

Re:Huh (2)

tlhIngan (30335) | 1 year,21 days | (#45003599)

There is not really a "soft" restriction on accuracy because none of us possess the decryption key for military carrier. Limits on accuracy is mostly caused by "ionospheric delay" from signals traveling thru charged upper atmosphere. Now that other GPS constellations are in operation it is possible to construct a receiver to concurrently examine timing/phase of multiple carrier frequencies to get an active handle on ionospheric delay and significantly improve accuracy. New civilian signals being added to GPS will also provide improved accuracy.

Timing/phase analysis is also useful if you don't need absolutely precise location information - but need rapid and high precision relative positioning information. (No one said you couldn't get your position first, then switch to timing/phase analysis to do high-resolution relative positioning).

This method has been used to study wildlife where the swooping of birds is fast enough that the GPS update rate was insufficient - the timing/phase GPS gave much faster position (or change in position) updates at the loss of absolution positioning.

Re:Huh (2)

Bob the Super Hamste (1152367) | 1 year,21 days | (#45004409)

You don't even need other GPS like constellations to do the necessary corrections. Differential GPS has been around for years as a simple solution and for more accuracy RTK solutions have been developed that operate with the US GPS. The biggest benefit of having multiple GPS like constellations is that you don't need your own reference station and can do it all in one device. Or you could do what the EU's Galileo system does and basically have 2 open channels providing data (the US GPS also has 2 channels but the L2 one is encrypted) which is how it can promise accuracies similar to RTK systems from a single device. The more data you have from different frequencies the more accurate you can get. I would love to have a module that could get the US L1 and L2 data, Russian GLONASS, and EU Galileo signals and be able to actively track 30+ satellites (most receivers only track at most 16) at once providing pseudo range and carrier phased data for all of them. Now that would be a very accurate system

Re:Huh (1)

dgatwood (11270) | 1 year,21 days | (#45003967)

Demand is pretty low I guess.

If so, it means that the hardware manufacturers are too clueless to recognize that it's a serious problem. I have GPS in my Canon 6D and nearly returned the camera because I thought the GPS had died after a week. Why? Because I had gotten on an airplane, which caused GPS to shut off internally, and it never came back on. After yanking the battery, it started working, at which point I thought for a moment, remembered that ridiculous restriction, and realized what had happened. Had I not been intimately familiar with GPS, Canon would have eaten several hundred bucks because of this limitation.

The reason people don't notice this on phones is that the phone knows to reset GPS if there's a cell signal. Unfortunately, non-phone devices don't have that advantage.

Re:Huh (1)

bill_mcgonigle (4333) | 1 year,21 days | (#45005457)

Why? Because I had gotten on an airplane, which caused GPS to shut off internally

Others here are saying that the required limits are 60,000 ft and 999 knots.

Did you take a particularly fun plane ride?

Re:Huh (1)

Pinky's Brain (1158667) | 1 year,21 days | (#45005379)

If you don't limit it your device falls under the Wassenaar agreement so it can't be exported from most western countries ... easier to just put in the limitation.

Re:Huh (1)

Pinky's Brain (1158667) | 1 year,21 days | (#45005389)

Or rather it can't be exported without jumping through expensive hoops.

Re:Huh (0)

Anonymous Coward | 1 year,21 days | (#45005231)

He speculates that his manufacturing source only let them do this because they were "clearly peaceful". No one cares if you're peaceful. They are a foreign (to the U.S.) entity using a non-minor modification, not available on the open market, to a controlled technology, which may allow to be used for military applications. This is a clearly brings it under U.S. FAR and ITAR regulations. If they do any business in the U.S. (likely), then they can essentially lose control of their IP and their ability to sell except to government or military only. Anyone who works on this kind of technology with any branches in the U.S. has lawyers who know or should have known this. I can't imagine any company actually approving of this. This mod is most likely the result of a conversation with an over-eager engineer who had no company approval to disclose the necessary modifications.

That being said, there are ways to get mil-grade GPS outside of the U.S., contrary to U.S. law. A portion of everything that goes to Israel eventually makes its way onto the black market. Most countries that are any serious threat in a hypothetical war already have the tech (notably China, which always has the invasion of Taiwan in mind as "just over the horizon"). As a historical note, this kind of propagation is one reason we felt comfortable offering our European allies the keys to the kingdom a decade ago. They decided they didn't like the idea of being dependent on the U.S. for their GNSS infrastructure, however, and instead fully committed to the Galileo project.

Predicting a future headline: (4, Funny)

walmass (67905) | 1 year,21 days | (#45002249)

In other news, amateur rocket organization Copenhagen Suborbitals recently reported theft of unspecified electronic components from its offices

Re:Predicting a future headline: (0)

Anonymous Coward | 1 year,21 days | (#45002349)

I'm sure any group that wanted a US military GPS and had the skills to use it stole one years ago. And the US military can still lock everyone else out of the system if they want to.

Re:Predicting a future headline: (1)

afidel (530433) | 1 year,21 days | (#45002633)

Actually, officially they can't. The last two generations of GPS birds do not have the circuitry needed for selective availability. And frankly given the number of consumer GPS units that have been used by the military in the field it would be kind of silly to turn it back on if they could.

Re:Predicting a future headline: (0)

Anonymous Coward | 1 year,21 days | (#45002829)

Actually, the U.S can. They can turn the signal off, or mess with it, for any region they like. Which they will probably do the day they fight a war with someone who actually uses gps-guided weapons. Which again is one of the reasons that Russia has its own system (Glonass).

If the al-quaeda starts using gps-guided drones in numbers, (which they probably can buy from China or Iran) you'll see just what tricks the US military can use. They own the system, after all. Even without "selective availability", it is still possible to turn off satellites or transmit wrong orbital data.

Re:Predicting a future headline: (0)

Anonymous Coward | 1 year,21 days | (#45002935)

when i was in the army all our GPS units needed an encryption key loaded before they would work

the military can send inaccurate civilian versions of the signal and the real one will be encrypted

Re:Predicting a future headline: (2)

Gareth Iwan Fairclough (2831535) | 1 year,21 days | (#45003343)

A lot of the gps hardware I saw as a supply specialist in the British army was just rebadged civilian gear. The really super gps gear that I did see tended to be for aircraft and the like, which tended to be bigger bulkier units than what a man would use on the ground. The guys on the ground would often simply use more or less stock civilian gps gear with a fancy case and maps for either the world or the AO if file storage space was an issue on that particular device. No encryption other than the fancy ones used in aircraft and the sneaky beaky types.

That said, this is merely anecdotal.

Re:Predicting a future headline: (1)

jacknifetoaswan (2618987) | 1 year,21 days | (#45003703)

Definitely relative to the service you were in. The US military, from what I've seen (almost nine years as a contractor on various systems), uses military grade gear with encryption. I don't understand all the signals, but I do know that they're not just a GPS chip from an iPhone.

Re:Predicting a future headline: (1)

chinton (151403) | 1 year,21 days | (#45002353)

A more realistic future headline will involve the Darwin Award.

Re:Predicting a future headline: (1)

MatthiasF (1853064) | 1 year,21 days | (#45002601)

Why bother breaking into their offices?

They are attaching these things to balloons and rockets with parachutes, so there is no telling where they will come down.

Just watch their website, find where the last GPS recording was sent and go to that spot for a free military-grade GPS receiver.

Re:Predicting a future headline: (0)

Anonymous Coward | 1 year,21 days | (#45003057)

Just watch their website, find where the last GPS recording was sent and go to that spot for a free military-grade GPS receiver.

You mean at the bottom of the Baltic Sea? Yeah, that will be sooooo much easier...

Re:Predicting a future headline: (-1)

Anonymous Coward | 1 year,21 days | (#45004159)

Just watch their website, find where the last GPS recording was sent and go to that spot for a free military-grade GPS receiver with which they (incl. the military) know exactly where to find you as soon as you turn it on.

There, FTFY

Re:Predicting a future headline: (0)

Anonymous Coward | 1 year,21 days | (#45002979)

In other news, amateur rocket organization Copenhagen Suborbitals recently reported theft of unspecified electronic components from its offices

A picture of their "office". [wikimedia.org]

No way anyone is getting in there...

Not for long (1)

hipsterdufus (42989) | 1 year,21 days | (#45002281)

Knock knock.
Whose there?
It's the government.
It's the government, who?
It's the government and we're here for our GPS units. Hand them over or be labeled a terrorist.

Look, some high up government person is going to read this, realize that some national security breach has potentially occurred, then send in the troops to reclaim those units. This won't take long.

Some people need to feel important.

Re:Not for long (1)

91degrees (207121) | 1 year,21 days | (#45002331)

Well, I may be wrng, but I don't think Copenhagen Suborbitals is too concerned about the US government. The Danes seem to be a little less paranoid about this sort of thing.

Re:Not for long (1)

Kristian vonBengtson (3027633) | 1 year,21 days | (#45005349)

Everyone things everything is illegal all the way down to questions like "how are you allowed to build your own space rocket". Well, since its not illegal - its legal.. The world is not that bad... If you play your cards right - work the right channels and diplomacy, many doors will open up...

Re:Not for long (1)

JustOK (667959) | 1 year,21 days | (#45002461)

Highly unlikely. Everyone has already been labelled a terrorist.

Bypass the limits (1)

fustakrakich (1673220) | 1 year,21 days | (#45002285)

And screw the 'authorization'. Switch to inertial nav once an accurate fix is acquired, and use a big enough weapon where getting close is good enough.

It's silly anyway (4, Informative)

John Burton (2974729) | 1 year,21 days | (#45002305)

Given that it's possible to build your own gps received from scratch anyway this seems little unnecessary. (See http://www.holmea.demon.co.uk/GPS/Main.htm [demon.co.uk] for someone who did) Ok so it's not trivial but it's certainly possible.

Re:It's silly anyway (2)

serviscope_minor (664417) | 1 year,21 days | (#45002505)

Came here to post something similar.

It's actually got a bit easier now, since you can get pre-packaged GPS to baseband chips which solve most of the mucking around with high frequencies stuff.

Re:It's silly anyway (1)

CastrTroy (595695) | 1 year,21 days | (#45002565)

My thoughts exactly. GPS has been around long enough. I don't believe for a second that Non-Friendly governments, or even hobbyists haven't already reverse engineered all the security protocols put into place to stop others from getting an precise location.

Re:It's silly anyway (1)

jacknifetoaswan (2618987) | 1 year,21 days | (#45003723)

You need the crypto-keys to be able to access the military channel. Civilian GPS is good, but as has been stated above, does not work at speeds exceeding mach 1 or at altitudes above 60,000 feet.

Re:It's silly anyway (2)

Bob the Super Hamste (1152367) | 1 year,21 days | (#45004493)

Civilian GPS is good, but as has been stated above, does not work at speeds exceeding mach 1 or at altitudes above 60,000 feet.

Buy a better receiver that implements it correctly as an AND instead of an OR as the law is written with an AND. Manufactures find it easier to implement it as an or for what ever reason. If you are doing custom electronics for a project such modules are cheap ($25-$30) and easy to find. It is even a selling point that is printed on most (look for ones that state they work above 60,000 feet) and quit trying to use a hacked Garmin, TomTom, or Magellan hand held for this.

Re:It's silly anyway (1)

jacknifetoaswan (2618987) | 1 year,21 days | (#45005115)

There is nothing in the code that's an AND or OR statement that can fix this, it has to do with the signals that the systems can receive and decode. Sure, they can receive the military signal, but they can't decode it, because they don't have the encryption keys. I don't think you have a workaround for that.

Re:It's silly anyway (1)

Bob the Super Hamste (1152367) | 1 year,21 days | (#45005683)

What are you talking about? My comment didn't have anything to do with the well known fact that civilian GPS units can't access the L2 data. My response was about the absurd assertion that GPS doesn't work above 60,000 feet or 1,000 knots. The law is written such that the or should be an AND but most manufactures seem to like to implement it as an OR such that their devices won't work if it is above 60,000 feet or going faster than 1000 knots instead of both cases being true like they should. This has become so problematic in the hobbyist space that a common selling point for GPS modules is that the device functions properly above 60,000 feet or faster than 1,000 knots thus implementing the rule correctly.

Re:It's silly anyway (0)

Anonymous Coward | 1 year,21 days | (#45004565)

This is silly. How do you think the GPS satellite is going to know what your speed/altitude is? This restriction has nothing to do with the military/civilian gps signals. It is simply a check in the firmware, which is why if you build it yourself you would not have the restriction.

Re:It's silly anyway (1)

jkflying (2190798) | 1 year,21 days | (#45004587)

It isn't the civilian channel that stops working at 60k feet/mach1, it is the receiver that decides to stop working if it senses these conditions. If you make your own receiver you can bypass these limits.

Re:It's silly anyway (1)

wisnoskij (1206448) | 1 year,21 days | (#45002899)

And I assume it is really really easy to hack the commercial ones.

Nice to see progress (1)

Plammox (717738) | 1 year,21 days | (#45002377)

This will undoubtedly help them time the drogue/parachute release next time. Unfortunately this failed last time in an otherwise successful guidance experiment [youtube.com] due to the accumulated error in the intertial navigation.

DANGER WILL ROBINSON! (1)

GameboyRMH (1153867) | 1 year,21 days | (#45002501)

This will get you on the Naughty List. Be prepared.

What's the big deal? (0)

RogueWarrior65 (678876) | 1 year,21 days | (#45002551)

A COTS GPS module will give you around 2 meter accuracy. One of the UBlox devices can talk to WAAS and get around 1 meter (supposedly). So my question is: why do they need any better than than?

And all this is going to do is convince the US government to turn selective availability back on and we're all screwed.

Nevermind (1)

RogueWarrior65 (678876) | 1 year,21 days | (#45002619)

Helps to read the article. It's all about height and speed.

Re:Nevermind (1)

grnbrg (140964) | 1 year,21 days | (#45002889)

That's what she said. :)

Re:Nevermind (1)

RogueWarrior65 (678876) | 1 year,21 days | (#45002971)

And all this time I thought it was about girth.

Re:Nevermind (1)

rikkards (98006) | 1 year,21 days | (#45003521)

Actually it is about the little man in the boat

Re:What's the big deal? (0)

Anonymous Coward | 1 year,21 days | (#45002969)

They don't need more accuracy than that, and they aren't getting more accuracy either.

But "consumer" gps units have artifical limitations built-in. They won't work if the device is too high up, or going too fast. Weather balloons go too high. Research rockets both go too high and too fast for these limits.

So they got a device without limits, and can now use gps in their research rockets and balloons.Still no more than 1m precision, but as you said - they don't need more.

Excess precision is not much use in military applications anyway. It seems nifty to put a rocket through the right window in someones hq. But a milimeter-precision gps won't help you with that. Sure, the weapon might know to the milimeter where it is. But world maps are not that precise - where exactly is that window frame in world coordinates? Houses are not built to such precision. There is continental drift. There is earthquakes - the one that ruined Fukushima, moved parts of Japan up to 19 meters. Much more than gps precision, and a real problem for re-building - whose land is this spot now?

Re:What's the big deal? (2)

mbkennel (97636) | 1 year,21 days | (#45005813)


"Excess precision is not much use in military applications anyway. It seems nifty to put a rocket through the right window in someones hq. But a milimeter-precision gps won't help you with that. Sure, the weapon might know to the milimeter where it is."

What matters is getting high quality fixes and velocity updates simulataneously and continuously while the receiver is moving very rapidly compared to ground and very high.

The properties which allow that also allow precise fixes for stationary ground stations which can integrate over a long interval.

When you're a ICBM re-entry vehicle going 10+ km/s, tiny errors in space make for big misses. Remember, a ICBM warhead goes from the stratosphere to target in about 3-4 seconds. A missile attack looks like "Hey what's that fast white dot do<BANG>"

Active Guided Rockets? (1)

gr8_phk (621180) | 1 year,21 days | (#45002675)

The actual use shown is with a balloon, so they got the altitude limit raise or removed. It's not clear about the speed limit. Also I don't know about other countries, but I asked some high power rocketry guys in the US about adding active stabilization and was informed that anything along those lines is considered a missile and would not be legal (in the US). Never mind what slashdot chose for a headline then.

Re:Active Guided Rockets? (0)

Anonymous Coward | 1 year,21 days | (#45002853)

The headline is taken directly from the wired-blog...

Guided rockets aren't illegal in the US (1)

Anonymous Coward | 1 year,21 days | (#45005367)

THey, are, however, munitions, and subject to all sorts of restrictions on the information you can disclose. They also might have other operational restrictions imposed by the local FAA office.

But really, if you start building guided missiles, you attract a lot more attention from the regulatory authorities. Do you REALLY want to have to control all your documentation in accordance with export control rules? Make sure the garage where your missile is stored is locked?

Not the least is that putting guidance on your rocket might make it uninsurable as a "hobby rocket" through Tripoli or one of the other High Power Rocketry organizations. And, I'll bet that none of those organizations would let you fly your rocket at their meetings/launch days, just because *they* don't want to attract more regulatory scrutiny. It's been enough of a pain with the BATFE and solid rocket propellants.

So now, you'd need to go out and build or rent your own test facility, do your own negotiating with the local FCC office when doing test flights, etc. That turns a project costing a few tens of thousands of dollars into one costing hundreds of thousands or millions of dollars.

Hardware or Software? (1)

Tokolosh (1256448) | 1 year,21 days | (#45003011)

"...removing the limits is a matter of getting into the hardware changing the code..."

What does this mean?

Re:Hardware or Software? (1)

Anonymous Coward | 1 year,21 days | (#45003109)

GPS modules usually have the limits in the microcontroller code, which is often an ARM chip. So, you get into the hardware, with your software patch.

Re:Hardware or Software? (1)

Kristian vonBengtson (3027633) | 1 year,21 days | (#45005425)

Its not a matter of changing the hardware but the coding inside.... thats were the magic is normally locked

Yikes (1)

T.E.D. (34228) | 1 year,21 days | (#45003255)

Am I the only one made a little uncomfortable by this?

Headline from next year: Copenhagen Suborbitals' new franchise office in the Gaza Strip is doing amazing business...

Re:Yikes (1)

ColdWetDog (752185) | 1 year,21 days | (#45003463)

Yeah, you probably are. If you've been following Copenhagen Suborbitals for a while you will realize that the only people they are likely going to kill are themselves.

Mostly harmless.

Re:Yikes (1)

Kristian vonBengtson (3027633) | 1 year,21 days | (#45005405)

Harming 3rd parties are our biggest concern... besides getting the rockets to fly straight, which pretty much has an potential impact on the first one...

GLONASS? (0)

Anonymous Coward | 1 year,21 days | (#45003331)

GLONASS, anyone? Does it have the same accuracy limitations imposed?

Re:GLONASS? (1)

jacknifetoaswan (2618987) | 1 year,21 days | (#45003801)

Yep, though the accuracy issues aren't what is changed with regards to civilian vs. military grade GPS units. The civilian grade units don't work above a certain altitude or velocity. Military grade units use a different signal with encryption, and can operate outside of these restricted envelopes, with a rough increase in accuracy (about 1m vs. 2m).

EE question. (1)

SuricouRaven (1897204) | 1 year,21 days | (#45003375)

What is the 'thingie' that looks like two diodes connected to the 0.47F cap? I can see the cap itsself is a backup power supply. I can see the resistor connected to it is to limit charging current so the inrush doesn't crash other things with the voltage dip. But what is the thingie before the resistor? The symbol looks like two diodes, one of which is shorted out to effectively remove it from circuit and the other simply positioned to keep the backup power from feeding back into the main rail - but then why use this three-pin thingie rather than a simple diode to do the job? Are SMD bipolar transistors just cheaper? Because it looks like one on the board. And if that's all it is, why not use the more recognizable bipolar transistor symbol?

Re:EE question. (1)

bruce_the_loon (856617) | 1 year,21 days | (#45004001)

Dunno what they are doing with it in that design, but the item is a BAV99 dual signal diode in a 3 pin SMD pack.

It looks like it is protecting the VCC line from the voltage divider driving the VBACKUP input, which could be done with a single diode, but it might be easier to handle or more reliable.

Re:EE question. (1)

SuricouRaven (1897204) | 1 year,21 days | (#45004323)

There's no voltage divider. Look at the cap. 0.47F. Not uF. F. It's an ultracap. Stores enough energy to run the GPS for a short time if main power is disconnected. The diode's function is to make sure that if main power is lost, the capacitor doesn't just put energy back into VCC. Given it's function, a low forward drop would be essential for that diode - the BAV is 0.7V, not hugely impressive. A schottky diode would do a better job.

SDR = GPS with no restrictions. (gnss-sdr.org) (2)

citizenr (871508) | 1 year,21 days | (#45004303)

http://gnss-sdr.org/node/50 [gnss-sdr.org]

You can do software GPS using $10 rtl-sdr dongles.

Geocachers everywhere just got a big chub! LOL (0)

Anonymous Coward | 1 year,21 days | (#45004503)

Geocachers everywhere just got a big chub! LOL I wonder how long it will be before super accurate handheld gps is available. Of course I'd rather have my smart be the hardware of choice. Although then somebody could hack my phone through its back door and use it for an accurate missile lock on me when I'm mowing my lawn. Damnit.

Why buy when you can build (2)

LoRdTAW (99712) | 1 year,21 days | (#45005361)

You can roll your own using off the shelf components. Though this may add a bit of weight if you use PC hardware, an FPGA, DSP, microcontroller or combination may be able to do fast real time positioning past the measly few Hz that vendor GPS modules offer.

First you need a receiver for the GPS signals:
https://www.sparkfun.com/products/10981 [sparkfun.com]

Then you need to process that data into a useful position:
http://gnss-sdr.org/documentation/sige-gn3s-sampler-v2-usb-front-end [gnss-sdr.org]

Honestly, applying munitions restrictions to fast GPS does nothing to stop anyone from building a cruise missile or other GPS guided weapons. All it does is impose silly restrictions that rogue nations, governments or peoples will simply ignore and work around while denying peaceful legitimate uses by ordinary people.

Re:Why buy when you can build (2)

LoRdTAW (99712) | 1 year,21 days | (#45005625)

I just read up on the civilian restrictions regarding fast, high altitude GPS and there aren't any restrictions imposed on domestic use, only export. So building or buying a GPS capable of achieving speeds over 515 m/s and 18 km altitude domestically in the USA appears to be legal as long as you don't export it.

Source: https://en.wikipedia.org/wiki/Global_Positioning_System#Restrictions_on_civilian_use [wikipedia.org]

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