Slashdot is powered by your submissions, so send in your scoop

 



Forgot your password?
typodupeerror
×
United States Technology

U.S. May Reduce Non-Military GPS Accuracy 772

ward99 writes "The U.S. government may be degrading GPS satellite signals, to cripple Iraqi forces' ability to use those systems during the war. This could potentially reduce accuracy from ~3 meters to over ~100 meters. Users depending on GPS systems may want to do sanity checks on any data returned by those systems during the war. The U.S. will do this by increasing the inaccuracies on the civilian C/A code, turning back on S/A (Selective Availability), by having the satellites deliberately and randomly return inaccurate information on where they are. S/A degrades GPS accuracy to only 100 meters 95 percent of the time and 300 meters the other 5 percent of the time. This will not effect the military P code."
This discussion has been archived. No new comments can be posted.

U.S. May Reduce Non-Military GPS Accuracy

Comments Filter:
  • by Inf0phreak ( 627499 ) on Wednesday March 19, 2003 @07:41AM (#5543050)
    shouldn't have scratched our own satelite project (named Galileo, IIRC)
  • Army's stuff (Score:5, Insightful)

    by SlamMan ( 221834 ) on Wednesday March 19, 2003 @07:41AM (#5543052)
    Don't like it, but it's the army's stuff. They can degrade it that far if they want to. Don't like it? Send up your own GPS satalites.
  • Not Globaly (Score:2, Insightful)

    by sigxcpu ( 456479 ) on Wednesday March 19, 2003 @07:43AM (#5543056)
    Since GPS requiers line of sight to the satalites there is no reason to degrade the service globaly.
    I'd be surprised if you would nothice any change in the US.
  • Sanity checks.. (Score:2, Insightful)

    by jkrise ( 535370 ) on Wednesday March 19, 2003 @07:43AM (#5543058) Journal
    " Users depending on GPS systems may want to do sanity checks on any data "

    Which sane person would rely on GPS data for something even as trivial as navigation? Incidentally, how does one check GPS data? Against another GPS??
  • by kEnder242 ( 262421 ) on Wednesday March 19, 2003 @07:45AM (#5543070)
    Last time they turned off the S/A during the war, cheaper that way using off the shelf gps.

    You can always have a radio broadcasting the offsets from a known location to compensate.
  • by Anonymous Coward on Wednesday March 19, 2003 @07:46AM (#5543074)
    Do they really know how much a captain depends on GPS these days, especially when it comes to passing in and out of harbors? I hope this won't wreck another tanker somewhere.
  • by MyNameIsFred ( 543994 ) on Wednesday March 19, 2003 @07:46AM (#5543076)
    Let me understand this, the head of a German Autoclub says the U.S. military MAY, I repeat MAY, degrade GPS accuracy. No evidence. Just pure conjecture. Consider that GPS has woven itself into our lives. How, it arguably supports critical functions. I strongly doubt that they will do this. While I understand the world's fears concerning GPS because it is run by the military, I put this article in with all FUD.
  • by bushboy ( 112290 ) <lttc@lefthandedmonkeys.org> on Wednesday March 19, 2003 @07:51AM (#5543100) Homepage
    But then again, there's not much fairness in this whole debacle.

    I'm not about to argue with that kinda military force - only a madman would do that ;)
  • by October_30th ( 531777 ) on Wednesday March 19, 2003 @07:53AM (#5543104) Homepage Journal
    Wouldn't funding and improving an existing system such as Glonass be less expensive?
  • Time to... (Score:2, Insightful)

    by skillet-thief ( 622320 ) on Wednesday March 19, 2003 @07:57AM (#5543125) Homepage Journal
    ... get the compass back out, I guess.
  • I was going to say that I thought they had figure out how to scramble or turn on SA where they wanted to. Do the editors check even the story? The newsline was frankfurt, not here in the good old US of A! The old SA is not going to be reinstated. Too many of our homeland thing depend on it. Planes, delivery persons and anyone else who needs to know where they are. Things are much different then during the gulf war. Many people depend on GPS's for at least some navigation.
  • Alternatives (Score:5, Insightful)

    by Bozovision ( 107228 ) on Wednesday March 19, 2003 @08:19AM (#5543225) Homepage
    And this is EXACTLY why the EU wants their own alternative civilian version of GPS [bbc.co.uk], and why the US has argued against it [cnn.com]. Suprise!

    Apparently the Pentagon sees no compelling reason [www.useu.be] for an alternative to GPS. Oops, that would be before they checked their GPS units round about now. Oh wait, I forgot, they have their fingers on the buttons, perhaps that why they can't see a compelling reason.

    Oops look; those pesky photons might interfere with each other [cnn.com]

    On the other hand, to be fair, the US could have just degraded the signal without announcing it. At least now ships and planes probably won't be piloted into rocks.

  • it *is* our stuff (Score:1, Insightful)

    by g4dget ( 579145 ) on Wednesday March 19, 2003 @08:25AM (#5543248)
    The military isn't a private entity. The military, and anything they own, is paid for by your and my tax dollars, and it is owned by the US government. We, the voters, get to decide how it's going to be used ultimately, by electing and kicking out the executive and legislative branches of government.

    Incidentally, the many billions of dollars of equipment the military is about to blow up in Iraq don't come from nowhere either--they are coming from the check you and I are sending to Uncle Sam on April 15. The war may amount to somewhere between 10% and 20% of our taxes. I hope it's worth it because it sure is a lot of money.

  • Re:Army's stuff (Score:5, Insightful)

    by EzInKy ( 115248 ) on Wednesday March 19, 2003 @08:26AM (#5543252)
    Army doesn't own it. People own it. The money spent on the satellites came from people's taxes.

    And the people (through their elected representives) gave the money to the Army for military use.
  • by Drunken_Jackass ( 325938 ) on Wednesday March 19, 2003 @08:29AM (#5543257) Homepage
    S/A has always been a bit of a farce. It can be circumnavigated (no pun intended) if you use Differential GPS.

    Basically, you set one GPS receiver up at a known, surveyed location and program that location into the unit. Then when the receiver trilaterates its position based on the information the satellites provide, it does on-the-fly corrections (You say i'm here, but i know i'm here). It can then use that correction algorithm to correct the positions of other receivers.

    Of course doing that part on-the-fly is a bit more difficult (read expensive) because now you have to invest in radio communications back and forth between the two or more receivers - but it's often done. There are even services that have base stations set up across the country that sell a subscription-based service for that purpose.

    Most times, survey firms just log the data and correct after-the-fact back in the office from the base station (the differentiator) located in the same area.

    All in all, S/A only imposes the error to systems that don't have the capability == money to do DGPS.
  • by nurb432 ( 527695 ) on Wednesday March 19, 2003 @08:30AM (#5543259) Homepage Journal
    I guess we all just pospone that trip to the wilderness to get away from things..

    Take a MAP ( remember those things? ) on your next road trip...

    After the war the service will return to normal.

    Besides, who said we had a right to use GPS anyway?
  • GPS jamming (Score:5, Insightful)

    by g4dget ( 579145 ) on Wednesday March 19, 2003 @08:31AM (#5543266)
    I suspect the Iraqis have little need of GPS--their military probably knows their country pretty well and they don't have much in the way of smart weapons.

    GPS is much more important to the US military, which does not have on-the-ground knowledge there. The US should be more worried about the Iraqis jamming GPS signals and other communications.

    Of course, so far, it looks like Iraq is pretty feeble militarily. I suspect the war will be over very quickly. Which brings up the question again: why are we going?

  • by Frodo420024 ( 557006 ) <(kd.nrognaf) (ta) (kirneh)> on Wednesday March 19, 2003 @08:35AM (#5543275) Homepage Journal
    Alternately, they could leave SA off alltogether, and just jam the GPS signal in the area that they are performing operations - the GPS signal is relatively weak and an ECM aircraft could easily block hundreds of miles of GPS reception while flying out of range of ground-based weaponry.

    No way would they jam the signal, they want to use GPS themselves.

  • by guybarr ( 447727 ) on Wednesday March 19, 2003 @08:35AM (#5543279)
    In the USian Army we required 100m accuracy for Armor, 10m accuracy for Infantry/dismounted folks. All of the instruction had these tolerances.

    Yes, but did you need these tolerences ? For infantry navigation, you usually don't (Except for some extremely bad terrain types, an infantry officer/noncom who loses himself in an 100mX100m sized square won't do any good anyhow ...).

    For precise indirect fire, you do, but then again, my guess is that the Iraqi artillery (both light and heavy) positions are already very well measured.

    The US army doctrine probably requires these accuracies simply because they can get it relatively cheaply. Nothing wrong with that; in fact that's the correct thing to do. But that does not mean an army can't fight well with less accurate equipment.
  • Like Galileo? (Score:5, Insightful)

    by gotan ( 60103 ) on Wednesday March 19, 2003 @08:42AM (#5543295) Homepage
    Well, it seems the US government isn't too comfortable [state.gov] with that and tries (german link) [heise.de] to make (german link) [heise.de] the EU abandon that project. Naturally the EU doesn't like [guardian.co.uk] depending on a US-monopoly for such an important system.

  • Skew the France! (Score:0, Insightful)

    by Anonymous Coward on Wednesday March 19, 2003 @09:06AM (#5543371)
    Since localizing skewed GPS signals is possible... Can the US Military please make it appear to the Iraqi's, that in fact, coordinates of advancing US Forces actually appear to be coming from a country slightly to the North and to the West?

    Then, the Iraqi's can send those missiles that they "don't have" straight to their bestest pal...Jacquey-boy.
  • Not new... (Score:1, Insightful)

    by Anonymous Coward on Wednesday March 19, 2003 @09:07AM (#5543377)
    This was already note here (close to Serbia/Kosovo etc) in the previous US military intervention. Some friends of mine do sailing and had already noted that their GPS devices had gone "crazy". At least this time they issued a warning (then again maybe they had warned back then, but I don't remember).
  • by north.coaster ( 136450 ) on Wednesday March 19, 2003 @09:14AM (#5543405) Homepage
    Here's [newscientist.com] what the US military has to say about this.

    The reality is that in the time period since S/A was turned off many businesses have become dependent on the GPS. If S/A were to be turned back on worldwide, then that would provide one more reason to oppose the war. COnsidering the current political climate, both in the US and worldwide, I can't see this happening.

  • Re:GPS jamming (Score:3, Insightful)

    by sql*kitten ( 1359 ) on Wednesday March 19, 2003 @09:31AM (#5543492)
    GPS is much more important to the US military, which does not have on-the-ground knowledge there. The US should be more worried about the Iraqis jamming GPS signals and other communications.

    Actually, given the satellite photos, reconaissance aircraft and special forces, the US/UK probably know Iraq better than most of Iraq's Generals by now. Look at who's in charge on either side: the Allies have professional soldiers with decades of experience on the ground in wars, peacekeeping, exercises etc all over the world. The Iraqis have various relatives and cronies of Saddam Hussein who probably never leave their palaces unless they have to.

    Of course, so far, it looks like Iraq is pretty feeble militarily. I suspect the war will be over very quickly. Which brings up the question again: why are we going?

    There are many factors to consider when evaluating military strength. One is power-projection, which is the ability to move your forces to where they're needed. The UK has a relatively small army (110,000 soldiers) but can partake in these sorts of adventures because it has the air/sea capability to move them around. Iraq (like North Korea, China and a few others) has a large military, but is unable to project them any further than neighboring countries. And while Iraq is militarily weak on a "global scale", it never intended to fight a global war - it was easily strong enough to take Kuwait, for example, and were it not for Allied garrisons, it could have taken Saudi Arabia, Oman and UAE without too much trouble.

    Even if you overlook the appalling human rights abuses Iraq's government is responsible for (including nerve gassing ethnic minorities), even if you ignore his sponsorship of Hamas (who admittedly aren't anything to do with al-Queda, but they're still terrorists), Saddam must not be permitted to invade his neighbors again. And yes, one reason for that is because if he gets control of all the oil, he can starve the West into submission.
  • Re:Gosh..,. (Score:2, Insightful)

    by dick johnson ( 660154 ) on Wednesday March 19, 2003 @10:15AM (#5543760)
    Oh Yeah. I forgot. The Europeans have always done such a good job cleaning up.

    Kosovo. Thousands of innocents murdered in their own backyard, but they're incapable of bringing themselves to do the right thing, until the U.S. steps in.

    Or, perhaps that failure was just a lack of European intestinal fortitude.

    It's so typically European. They'd rather have stable despots than the liberation of millions of people. This isn't only a recent development.

    The cowardly response to the above will be that stability is better than chaos where millions may starve.

    But that's a position that is could only be held by people who've been protected for the last 50 years by the American Taxpayer. A people, I might add, that have for several decades now not known what it's like to live in fear of tyranny.

    How many hundreds of trillions of dollars have Americans spent to maintain the current European lifestyle? This is money that was spent on European defense, but ultimately, allowed the Europeans to neglect their own defense spending and focus on domestic needs.

    The only reason western Europe has the luxuary of looking down its nose at the U.S. today is that they've essentially been a collection of welfare states of the United States for the last half century.

    I for one hope we bring an end to that situation very, very soon. Let the Germans and French worry about their own security. And if the Russian experiment with democracy fails, let's see how critical these same people will be of America then.

    Britain aside, NATO has become nothing more than a Welfare program for Western Europe. We stand by them when the Russians are at the door. But where are these folks when we tell them we need them? It's a one-way relationship. One that the American people need to reexamine.

    The very threat of military retaliation by the United States allowed western Europe to remain free during the cold war.

    Let's see how the European economies do when they have to increase their portion of defense spending, to offset the end of American subsidies. (The only reason European countries have been able to spend so little of their Gross Domestic Product on defense these past five or six decades)

    Europeans complain of "The American Empire," as a previous post put it. But I for one would love to see a time arise when my country could go back to being an isolationist one. But ultimately, the same spineless folks who complain about the U.S. today, will be the same ones clamoring for our help tomorrow.

    It reminds me of something the comedian David Letterman said after the fall of the Berlin Wall. He had a list of the top 10 things the French were doing to prepare for German reunification.

    Number one was "Practicing Blowing kisses while marching backwards."

    -dj
  • by Reinout ( 4282 ) <`reinout' `at' `vanrees.org'> on Wednesday March 19, 2003 @10:16AM (#5543772) Homepage
    Civilian GPS in gulf war 1 [pbs.org]

    Look at the second paragraph from the bottom. They were about to reduce the usability of civilian GPS systems during the first gulf war. Turned out that many military personell was carrying their own, civilian, equipment. It wasn't standard issue back then yet.

    So they left the resolution cranked up to max, their own soldiers would be most hampered by a downgrade...

    Reinout
  • by Anonymous Coward on Wednesday March 19, 2003 @10:24AM (#5543806)
    1) Unless you're using GPS for something like surveying (you aren't. admit it.), this doesn't matter. If you can't navigate while hiking/biking/driving/flying/boating with 300 feet of accuracty, then you suck, and you shouldn't be doing it anyway.

    2) Are you telling me Iraq needs more than ~100 meters of accuracy to make their attempt at defense? "hmm...I know that gasoline-filled trench was around here somewhere...hmm...where should i drop my torch...duh...."

    Come on.
  • by f97tosc ( 578893 ) on Wednesday March 19, 2003 @10:25AM (#5543815)
    shouldn't have scratched our own satelite project (named Galileo, IIRC

    I am from Europe myself but I am not sure I agree. The reason Galileo is not going anywhere quick is that is enormously expensive (just as GPS was).

    Is it really worth the money and the effort to send up an entire system so that coverage can be ensured during the say 2% of time when the GPS signals are distorted for military reasons? I can see a any number of scientific/ infrastructure projects that are much more worthwhile. Of course, European taxpayers never were as stingy as the Americans.

    Tor
  • by forgoil ( 104808 ) on Wednesday March 19, 2003 @10:53AM (#5543984) Homepage
    Maybe the French has threathened to veto? ;)

    All dumbs jokes aside, EU really really needs to get a GPS system of our own. We should of course let the US use it, and use the original GPS when appropriate (for example extra accurcy or if one fail etc). It is fairly dumb to give away so much power to a foreign military.
  • by pebs ( 654334 ) on Wednesday March 19, 2003 @10:55AM (#5544001) Homepage
    Isn't that a bit like saying. It isn't your car - the money used to buy it was given to you by your employer.

    Well, no.. its more like you split the cost of your car and its maintainence with 200 million other people. And also you elected a driver and split the cost of this as well. You're not allowed to drive the car, but you can be one of the mechanics but you have to give up some of your rights as a passenger. You also have some input as to where the driver takes you, but this is split between all the people as well. This might have to be a larger vehicle, because 200 million people don't fit that easilly into a car; in which case everyone has to spend a little bit more.
  • by sphealey ( 2855 ) on Wednesday March 19, 2003 @11:29AM (#5544221)
    This was *exactly* why we here in Europe shouldn't have scratched our own satelite project (named Galileo, IIRC)
    I would have a hard time seeing the EU not including exactly the same capability in Galileo, since control of precision targeting capability is critical for national defense. Of course, perhaps the EU is anticipating that it will have no concept of national defense by the time Galileo arrives.

    sPh

  • by Oswald ( 235719 ) on Wednesday March 19, 2003 @11:42AM (#5544285)
    I don't understand. How is it paranoid to think that your enemy in war may want to kill you? How is it idiotic to deprive them of a useful tool?

    This article [newscientist.com] says that the DOD has better ways to achieve this end, so you can stop crying. But, if degrading the signal worldwide were the only way to degrade it for the Iraqi military, they would be correct to do so.

  • by Anonymous Coward on Wednesday March 19, 2003 @12:25PM (#5544581)
    "Don't create competing products, because the USA already has made them". What happened to the capitalist ideals about competition in the market?
  • by jvaigl ( 649268 ) on Wednesday March 19, 2003 @12:28PM (#5544599) Homepage
    It's an interesting discussion, but doesn't look like it's going to happen. The article they're referring to is just some German auto club that says the thing maybe it could happen when the war starts. Hardly authoritative.

    The official sites to monitor if you're worried:

    www.igeb.gov [igeb.gov]: The IGEB is a senior-level policy making body chaired jointly by the Departments of Defense and Transportation. Its membership includes the Departments of State, Commerce, Interior, Agriculture, and Justice, as well as NASA and the Joint Chiefs of Staff.

    Right after 9/11/01, they posted (still there) this: "GPS Selective Availability (SA) has not been used since its deactivation by the President on May 1, 2000. At that time, the United States Government stated that it has no intent to ever use SA again. There has been no change in this policy."

    http://www.navcen.uscg.gov/gps/default.htm [uscg.gov] is the official source for notices to civilian GPS users about schedule satellite outages, etc. They have nothing related to S/A being turned back on, and they certainly would if it were going to happen.

    We can jam or dither the civilian code over the theater if we need to.

  • by Hentai ( 165906 ) on Wednesday March 19, 2003 @02:30PM (#5545693) Homepage Journal
    And you think for ONE SECOND the US military will allow this?

    Think about it - the whole reason they turn down accuracy is to keep their enemies from accessing the technology. If the US military doesn't CONTROL the technology, how will they keep their enemies from accessing it?

    At the point the enemy starts using an open GPS, it becomes, de facto, an enemy asset, and thus targetable. I give it six weeks into the first engagement after a EU GPS becomes reality before the US gives the EU an ultimatum: Shut them down or we'll blow them out of the sky.

    And don't think we won't.
  • by plopez ( 54068 ) on Wednesday March 19, 2003 @02:48PM (#5545877) Journal
    The comapny I am currently working for (an Env. Engr. firm) requires 15m accurracy for field work. We work with a number of large energy companies, state and federal regulatory bodies and we even are working with DOD and Army Corps of Engineers. If we cannot get good readings, we (and our clients) are out of compliance. Also, doing groundwater studies with 100m to 300m accurracy is also unreasonable.

    GPS has become so embedded in our society, that this move just isn't viable anymore, IMO.

    Is anyone else in this same situation?
  • Re:Sanity checks.. (Score:3, Insightful)

    by zCyl ( 14362 ) on Wednesday March 19, 2003 @04:36PM (#5546867)
    Boy, it's a good thing Galileo, Magellan, and Columbus all had their trusty GPS systems available back then, isn't it?

    Columbus thought he landed in India.
  • Re:buy a cluestick (Score:3, Insightful)

    by Bastian ( 66383 ) on Wednesday March 19, 2003 @05:10PM (#5547117)
    Yes, GPS is damn useful. It will be an inconvenience for lots of people if SA is turned back on.

    But, if you're putting yourself in a situation where you could die because SA is turned back on, you need to rethink your nautical habits.

    Personally, I wouldn't want to be in a line of business where I have to be navigating narrow waterways at night such that I would need to trust a GPS receiver to keep me on the water. Even if I did have to navigate such a waterway at night, I'd rely mostly on my current technique, which seems to have worked just fine so far: artificial light. Buy a damn searchlight or two and put them on your boat for at night. And if a searchlight isn't enough to help you safely navigate whatever waterway you're navigating at night, you deserve whatever is coming to you, GPS or no GPS. If your line of work or somesuch requires that you do this every so often, I would recommend you find another line of work.

    If you're waterskiing or sailing in a place where you would need ~3m accurate GPS information about underwater obstructions, you also deserve what is coming to you, and I'd be inclined to list your death under the "natural selection at work" column rather than the "what a horrible accident" column.

    As for finding submerged obstructions, I'm sure that if you have proper charts (which should be shown on your GPS receiver's screen) and look away from your GPS receiver to see the lay of the land every so often, you should be able to figure out where the obstruction is. Maybe not to ~3m accuracy, but close enough that you can avoid it. If you are in open waters where you don't get good landmarks to work with, you should easily be able to give the obstruction a 1-200 meter berth rather than a 3 meter berth (and general common sense would suggest that you should make this standard practise when in open waters, anyway). If you're doing this in an area where you really do need GPS's current accuracy levels, see my comment about natural selection above.

    As for whether or not it is sane to think that turning SA back on will kill people, I think that it quite obviously will. No matter how stupid it is to put oneself in a situation where GPS is that important, people will do it. Some of them will probably be speeding down a twisty river with sandbars while pulling a waterskier at 2AM on a moonless, overcast night. These people will hit the shore, and a lot of them will be seriously hurt, some may die.
  • by pizpot ( 622748 ) on Wednesday March 19, 2003 @05:24PM (#5547235)
    French Fries--> Freedom Fries--> Democracy Fries--> Democracy but don't vote against us Fries--> Dictatorship Fries!

Stellar rays prove fibbing never pays. Embezzlement is another matter.

Working...