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U.S. May Reduce Non-Military GPS Accuracy
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."
shouldn't have scratched our own satelite project (named Galileo, IIRC)
________
Entranced by anime since late summer 2001 and loving it ^_^
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.
Mod point free since 2001
This may seriously affect my handy-dandy Honda navigation system built into my Odyssey - it already has trouble guessing which road I'm on when the roads are close together - imagine it thinking I'm a block away from where I really am.
" 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??
If you keep throwing chairs, one day you'll break windows....
This means that my grand dad can get lost in forrest while picking up mushrooms. I can get my legacy faster. :)
Would be interesting to know what the EU would do with Gallileo at this moment in time. I dare say they would follow the US lead, I suppose...
The article is German centric and talks about effect on people in Germany !! Any idean if it will impact US GPS systems?
...by having the satellites deliberately and randomly return inaccurate information on where they are.
;)
Isn't that supposed to be terrorism ?
Karma cannot be described by words alone.
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.
my associative arrays can kick your hash - TCL
My guess is that for high-precision locations, the Iraqis already measured them with high accuracy, while for, say, infantry navigation all you really need is 100m accuracy. (Even less for armored forces, of cource)
And given the air threat, I also doubt their forces will change their localtions too much; if it's camouflaged enough to survive the initial attacks, it will probably stay put.
Working for necessity's mother.
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.
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.
Civilian planes use GPS, don't they?
What about other critical systems like police, ambulance, fire brigades and so on??
Can someone comment on feasibility of Differential GPS infrastructure for country that hasn't got own satelites, but wants to secure precise locating ability for services from 911 to Public transportation.
There are plans for building a similar system to GPS in Europe so that we are not too much depending on the american empire. The following page nicely explains the concept. More is available here . This is technically very interesting and should open up new possibilities for navigation. Furthermore being constructed jointly by many partners and nations we can be reasonably sure that it can not be compromised by one weak leader.
Googlefight "Slashdot Troll" against "BSD is dying" 303:229. BSD thus cant die.
Because it is encrypted.
"It's too bad that stupidity isn't painful." - Anton LaVey
Can't wait for the european system to be up and working. Nothing better than a little competition. And hopefully the us and europe will never be at war at the same time.
Fleur de Sel
John R. Smith, of Peoria (Ill.) drove his brand-new SUV through the security glass doors of his bank, while following his GPS navigator.
"I was only following the indications of this @!!%!! machine -- and it told me I still needed to travel straight ahead for a hundred meters!", Smith tried to explain as he was taken into custody by the Peoria Police Department for "breaking and entering".
The Peoria Intercontinental Bank representatives were unavailable for comments.
The right to offend is far more important than the right not to be offended. (Rowan Atkinson)
There is a better alternative to GPS named STDMA (Self-organizing Time Division Multiple Access). It is patented with U.S. Patent No. 5,506,587, which you may find HERE.
It is in use in marine navigation. See also HERE and for a tech overview HERE.
Apparently, the US has tried to suppress the system as it may well replace GPS because of better performance and other reasons; one can imagine wartime control may be of importance here.
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
A slashdotting - you get the stick first and then the carrot !
It's more likely that localized blackout or jamming in the Iraq region will be used, rather than a global downgrade. See here for more.
--
CPAN rules. - Guido van Rossum
I mean I know they sold them Anthrax, but didn't know about the GPS euipment ;)
If Google really cared they would fix Android Chrome to reflow text, instead of discriminating
It is not so well known that the russians have a system similar to GPS. More information at http://www.rssi.ru/SFCSIC/english.html
Because that would defeat the purpose of the military code.
GPS 101:
Every GPS unit stores internally a fairly accurate clock, a database of every GPS sattelite's individual code and its expected position in the sky for something like the next few weeks. This information is updated by syncing with a sattelite every so often. These codes are long enough that based on what portion of the code the receiver is receiving at a given time from a particular sattelite, it can calculate the time elapsed since the signal left the sattelite (by comparing to what portion of the code the sattelite should be transmitting according to its internal clock).
Using time elapsed, and roughly the speed of light (with minor corrections) for the speed of the wave, it can then calculate distance from the sattelite. Given three sattelites, you narrow down your location to one of two points (the maximum number of points of intersection of two non-congruent spheres. Luckily, one of these points is almost always inside the earth or in outer space, so a fourth sattelite isn't needed for that triangulation.
A fourth sattelite is used, however to make corrections for the GPS receiver's internal clock. That is, the receiver assumes its clock is off of the atomic clock in each sattelite by a constante amount, and therefore a fourth sphere won't intersect either of the points of intersection. However, by correcting for a constant time difference, the points of intersection eventually line up, and that is a fairly good approximation of the unit's location.
This means, by telling the sattelitest to vary the rate of transmission of their own unique code in some random way, the accuracy can be made much lower.
Since the system is based on knowledge of the codes, and only the civilian codes are published, the military codes look like just noise.
So there you have it - if the military doesn't give us the necessary information about the sattelites (information that changes every so often), we have no way of using the military-level accuracy.
Shout it!
People who get this wrong really need treatment.
I used to fantasise about setting up a "Remedial English Grammar" course at my last workplace, but the #1 person who needed to be on it was the Managing Director.
I think the reason this particular example gets me so angry is because everyone knows that "X is affected" is correct, but some people think that "X is effected" means the same thing and sounds "cleverer". So "X is effected" doesn't just mean "I am ignorant" (many people can't help that), it means "I am ignorant, but I think I am clever".
What would that help? Are you saying that you are against the idea of scarambling the singnals when neccessary to prevent Iraqi missiles bombing our asses?
If Iraq are stupid enough to design technology to use during war, that relies on a signal transmitted by their enemy, I believe the idea of dissrupting that signal - locally and temporarily is very sly indeed.
What I find distrubing in the article is that newer GPS receivers wont be affected. How does that work, and isnt that a flaw unless they know for certain Iraqi missiles rely on the 'old' technology?
-ccm
Too much Law; not enough Order.
It's not like they're sabotaging a civilian system. The GPS sattelites are owned and run by the US government. It is sheerly at the government's discretion with whom they share information needed to use the sattelites - I suppose, in theory, they could mute sattelites when they were out of the line of sight of the US (though that wouldn't really serve a purpose).
I guess their choices are to move the tagged prisoners back to jails, deal with implications of the reduced certainty of location (i.e. harder to use as evidence) or to move to another technology.
It will certainly lead to the prisoner's virtual boundary being made 90 metres wider which will make it a lot easier for a criminal to disassociate him- or herself with a crime.
Powered by onion juice.
It's a system for VHF communication, meant for ships to automatically transmit their positions etc. to each other.
This sig under construction. Please check back later.
I thought about encryption, but then I realized - no actual information is sent in the bits - all information is derived from timing. Encrypting an already arbitrary stream of bits seems a little... fruitless to me.
I would not expect them to be overly concerned on this, It would be more effective to use nuller spot beams from a geosyncronous byrd,(like those on the MILSTAR constellation) than to play with the GPS system, that has multiple civilian uses at the edge of it region ( i.e. areas not affected by the war, but still in its reigon... Saudi, Turkey, Israel.) The use of ground based jamming equipment and space based nullers should give a more controlled area of comms blackout, and increase the chance of misnavigation more than messing up sadams backpacker gps...
Oh yeah, the American "empire". Well dude, I am a European (Finland), but I don't think the American "empire" owes us anything. GPS is just a present to the world, not anything US was obliged to do.
:o)
And if you're French by any chance: next time the nazis are sipping cofee in Paris, I hope you ask for the "inspectors to have more time".
Sigged!
First guess says you need satellite access codes
Yep.
Second guess says the stream is probably VERY well encrypted.
Possibly but I doubt it. The technology is rather old and I don't believe that the code used is that clever. More importantly, there are an awful lot of manufacturers that know the codes. It wouldn't surprise me if the code has fallen into the wrong hands. (I've seen somebody type the code into a military GPS receiver that had lost its keys as he knew it off the top of his head. This is not the way it is supposed to be done....) Finally, you would expect the code to be changed regularily as well......
Third guess says that if you access the military channels...
Nope. The channel is one way only. You can try and decode it as much as you want as your GPS receiver does not have to send anything back. If you manage to decode it, good luck to you, the US mil won't know you are doing it.
wot no sig
You got it wrong, I'm afraid.
The patent covers a position INDICATING system, not a position FINDING system.
STDMA depends on GPS to deliver an accurate timing signal. The timing is then used to pick the right time to transmit in "your" timeslot on the shared radio frequency.
The links you included even suggest that the marine transponders using this technology should transmit their positions - which is also delivered by the GPS.
-- From Denmark
Apparently the Pentagon sees no compelling reason 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
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.
There will be a war with Iraq within a few days.
The coalition against Iraq counts 30 members at least. Quite a few of these are European.
-- From Denmark
"Hell we still can't hit a Barn Door from 200 yards" says General Norman Bates.
I think I'd almost prefer the feeling that the miltary blew up a hospital because they had the wrong data for accuracy, rather than a feeling that they did it on purpose.
An Eye for an Eye will make the whole world blind - Gandhi
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.
Don't a number of commercial services like onstar use gps to track vehicles?
'Be calm madam, you are not lost. According to us you are floating off the coast of San Diego. You should be fine once high tide rolls in.'
"I only speak the truth"
Karma: null(Mostly affected by an unassigned variable)
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.
There are 01 types of people in this world. Those that understand binary, and me.
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?
---- Booth was a patriot ----
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?
No, there is information in the GPS signal. e.g. where the satellite is. What time was it when the satellite sent the signal. Where are all the other satellites (every now and again).
All I want is a secure system where it's easy to do anything I want. Is that too much to ask ~~ Randall Munroe
Dude, it's from the head of a German Autoclub. The head! Not some secretary or anything.
Before and after the previous Gulf War, we had S/A "jamming" by the military, resulting in "errors" of about 10 to 100m.
During the last GW however, the US military disabled the jamming, because they were unable to produce military grade GPS receivers. They gave "normal" civilian GPS receivers to officers and disabled the jamming, thus defeating the entire purpose of the S/A system...
This was one of the reasons they turned it off a couple of years ago.
have bounced.
Harpo Tunnel Syndrome--my wrist feels funny.
Well, it seems the US government isn't too comfortable with that and tries (german link) to make (german link) the EU abandon that project. Naturally the EU doesn't like depending on a US-monopoly for such an important system.
"By the way if anyone here is in advertising or marketing... kill yourself." -- Bill Hicks
... And the government is owned and run by the people of the US who are civilians.
While leaders in the government may not always do what we want them to do, we DO ultimatly have control via the Vote. If we REALLY want to, we can vote evey single person in office Out, and replace them with people more in line with our views.
That said, most ignorant people vote for the person with the best hair and most money, which really skews the system. Your job, should you choose to accept it, is to educate the general public on what exactly the current people in government are doing.
Ick, that would be bad for Nascar who use military grade GPS for timing and scoring their cars.
"Woah Mark Martin appears that Mark Martin is making laps around the walmart..."
All you need is the nuclear missile and the 100m doesn't matter anymore.
There is nothing wrong with being gay. It's getting caught where the trouble lies.
Well, suddenly my favourite past-time appears like it's going to be a lot more difficult.
"How can the cache be 100 meters to the east? I'm already standing knee deep in the Atlantic Ocean!"
And I was looking forward to geocaching this weekend!
We found out the hard way that gps is absolutely useless when it comes to telling you which road is the local station road to check windmills and which is the through road to the next town. Guess which road gets used more? No the town road aint it! And don't get any ideas about driving off road, we punctured six tyres in 3km. We could have walked faster.
Hmm, I suppose the USA military mods will affect satellites over Australia and probably leave the ones over Iraq alone. I'm so glad the Canadians decided not to go. I'm worried for the Aussies that have. Hopefully they will factor their own error into GPS reports for the USA bombers. Hmm is that a Chinese Embassy or a TV station?
-- it must be true, it's on the internet.
I used to fantasise about setting up a "Remedial English Grammar" course
You REALLY need to get a life. Seriously.
GPS was never really meant as a highly accurate positioning system for civilians in the first place. The GPS satellites carry what is called an NDS package or Nuclear Detonation detection System. This package uses various methods, including visible light, EMP, X-ray, and Gamma Ray sensors to locate nuclear detonations. It is this package that uses the GPS positioning most accurately because it is colocated ON the satellites themselves. Along with this, the encrypted military positioning signals are used to guide military craft and munitions to their final destinations. The civilian positioning signal is purposely less accurate than the military signal. This is, after all, a military owned and controlled system. I was in the USAF when GPS Block 2 satellites were first going up, and in a group called AFTAC (Air Force Technical Applications Center) that ran the NDS as part of the 1963 limited test ban treaty monitoring system.
> And if you're French by any chance: next time the :o)
> nazis are sipping cofee in Paris, I hope you ask
> for the "inspectors to have more time".
Oh, and if Lafayette hadn't come to help save your collective asses from English tiranny, you all would still be speaking english today !
err... wait a minute...
Votez ecolo : Chiez dans l'urne !
You need to broadcast those corrections to all the GPS units in the field real time, so anything broadcasting corrections is a invitation to recieve a missile double quick time.
Donte Alistair Anderson Roberts - hi son!
Karma: Chameleon
If you can't have military-level accuracy, you just need a bomb that would make up the difference.
You think that I'm crazy, you should see this guy!
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).
It appears this measure would likely cause more nuisance and annoyance to Europe than Iraq. Do the Iraqis drive GPS navigated cars? Seems unlikely, given what we hear about the economy there.
The Iraqi military is unlikely to depend on unreliable US controlled GPS data for it's own defence.
This strategy seems like Microsoft releasing a Service Pack to quash Mozilla, in the name of fighting Opera.
If you keep throwing chairs, one day you'll break windows....
For all your GPS news and status.
http://www.navcen.uscg.gov/gps/default.htm
yes, www.dotcomforwardslash.com is my real URL.
Similarly, the US government is building more of its own non-web internets to protect itself during DDOS attacks. Once the government is no longer a potential victim of DDOS attacks, a shut-down of the Internet could become yet another useful wartime tool.
Making trouble today for a better tomorrow...
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.
Put simply GPS Satellites just tell you the time they send a signal. A GPS receiver gets a time signal from 3 (2d fixes) or 4 (3d fixes) satellites and since each signal takes a finite time to arrive, the distance to each satellite can be calculated. Knowing the distance to each satellite means you can find your position by means of triangulation.
Note that in Iraq, it is likely that in any 24 hour period nearly all the 21 or so satellites that are used in the system may be used to determine position, as the satellites are not stationary over the earths surface, and satellites that are used to fix postion in Iraq will at some time or other be used to fix position all over the world. You can't disable GPS fixes for a specific region.
Yes, I do know that time has to be solved for as well, I'm trying to keep the explanation simple, OK
Donte Alistair Anderson Roberts - hi son!
Karma: Chameleon
If civilian GPS is degraded outside the Gulf region it's going to affect boats.
SCUBA divers going wreck diving would be affected - it can be hard enough to find a wreck if it isn't bouyed using GPS without introducing an error factor of 100m-300m.
Have pleasant memories of using a GPS unit as a giant etch-a-sketch on a RIB with twin 80 horsepower outboards. (I know, not responsible but fun)
It's essentially the same thing. The accuracy is degraded by offsetting the clock just a little bit. We're talking errors of only miliseconds here so you can still set your watch by GPS, but it's enough to throw in an uncertainty volume into the computed position. Remember that the position is actually calculated by the GPS device through the differences in received timestamps (simple version of how it works).
This has been discussed before.
Look at
http://www.igeb.gov/sa.shtml
They say it will NEVER be turned back on
also see
http://www.navcen.uscg.gov/
-- 73 de KG2V For the Children - RKBA! "You are what you do when it counts" - the Masso
In the last Gulf War, they turned off SA so that the commercial units all of the soldiers had bought would know where the minefields were.
...or was it Bosnia?
People who disagree with you are not automatically evil, greedy, or stupid.
That is a terrible idea. The military should be able to defeat Iraq without having to reduce GPS signals. This will impact where I work because we make agricultural navigation systems for aircraft. Try explaining to a family that we sprayed chemicals to kill weeds on their house and see how happy they'll be.
How much will this affect civilian aviation now that it has allowed some dependence on GPS for instrument approach? I haven't been around the aviation world for a few years but I'm hoping that instrument rated private planes still require the more traditional VOR/approach equipment.
GlobalSecurity.org has posted an interesting FAQ on the war and GPS. It's located here . It was written by Richard B. Langley from the Dept. of Geodesy and Geomatics Engineering at the University of New Brunswick. It's a good read and answers a lot of questions about GPS and general and possible routes the military can use.
--Nyght--
Pardon me, but the last time I checked orbital mechanics defined the position of a satellite rather well. Therefore it is possible to say if we disable/degrade this satellite at this time, and then that one at such and such a time, performance will be severly curtailed in such and such a region. I would tend to suspect that the US military has the capability to do this selectively. ( I would, if I owned the system)
Or will i end up driving to Iraq instead of the pizza place? I don't think this will affect stuff that much. 100 yards is still pretty close.
stuff |
It has been the policy of the Interagency GPS Board that Selective Availability would never be turned back on, mainly because there are so many civilian users the rely on the more accurate signal since it was turned off. It would be a huge public relations blunder for the government if it did.
p ort/2003/iraq-and-gps_faq.pdf.
But before SA was turned off, the Air Force had to develop a capability called "Selective Deniability" that would allow it to alter the accuracy of GPS signals over designated theater of operations. I seriously doubt that SA will be re-enabled systemwide.
Someone on a listserv I belog to send the URL of this PDF dated 13 March, 2003 that adddresses some of those questions. The URL is http://www.globalsecurity.org/military/library/re
I don't remember American aid during that war having been conditional on agreeing with America on every subject from then until the end of time.
It is fairly awful to expect that because you help someone they then are your slave forever. Your help may not be required if those are the conditions.
Carpe Daemon
Actually, most units have a 12-channel parallell receiver, so it can do a pretty job and narrow your
position within 9 meters. 4-channel GPS units are things of the past (or used sometimes when size
matters more than accuracy).
Also, there are a "new" addition to the GPS system called WAAS (wide-area-augmentation-system) which
uses differente sattelites (this ones being geo-stationary) to send differentials information about
the GPS's sattellites signals. This way, a civilian WAAS-enabled unit like mine (garmin etrex vista)
can have an accuracy of about 3 meters, in theory. I find WAAS pretty dodgy and dont tend to use it
much because of higher battery comsumption and higer CPU usage, for a small improvement in the
accuracy (I mostly use the GPS in the car, so...)
cheers.
``If a program can't rewrite its own code, what good is it?'' - Mel
While it's hard/impossible to obtain a receiver that can directly use the P code, it IS possible for a civilian receiver to use the encrypted P code for additional accuracy without decrypting it.
i n.htm and http://www.nottingham.ac.uk/iessg/gringo/
The civilian C/A codes are only broadcast on one frequency. Both the C/A and P codes are pseudorandom bit sequences designed to have a very high peak in their self-correlation function. (Effectively turning the CW transmitters on the satellites into high-power pulse transmitters as far as SNR requirements at the receiver.) The encrypted P code has a much lower peak in its self-correlation function, but it STILL has a peak.
The C/A code is only broadcast on one frequency, while the P code is broadcast on two frequencies. Why? Because one of the leading sources of error in GPS reception when SA is turned off is the fact that the ionosphere delays the signal. Fortunately, the ionospheric delay is a linear function of the frequency. (I.e. a signal at 1.7 GHz is delayed 1.7/1.2 times as much as a signal at 1.2 GHz). So, a military receiver can measure the delay between the two frequencies, and from that calculate the ionospheric delay.
Now go back to the fact that even the encrypted code has a peak in its self-correlation function. A high-end civilian (usually surveying) receiver can receive the encrypted P-codes and correlate them (since they happen to be identical). Since the self-correlation peak of the encrypted code is much lower, the signal strength must be higher than that for unencrypted codes and the process is SLOW, but it can be done. Receivers capable of this cost $$$$$$. (For example, in the GPS lab at Cornell University, they have only 1-2 dual-frequency receivers, while they have plenty of single-frequency receivers on ISA cards to allow for advanced postprocessing of data.)
As far as SA - Even when SA is on, it's possible to get millimeter accuracy from a civilian receiver, using the same techniques needed to get millimeter accuracy from a civilian receiver with SA off. The most important thing is a "reference receiver" nearby - One whose location is precisely known. This receiver can measure all of the errors generated by the satellites, which can be used later to postprocess the data from a remote receiver and correct it.
In addition to clock dithering, SA puts errors in the satellite ephemerides (The description of their orbits). It's possible to download precise (even better than non-SA) ephemerides from various standards organizations for post processing.
Want to try post-processing yourself? Until recently, the answer was "tough luck" with the exception of expensive receivers and the Delorme Earthmate. Only the Earthmate allowed the user to capture raw pseudorange data (The data needed to obtain a navigation fix) for later processing. Fortunately, some people found out that it was possible to obtain pseudorange data from 12-channel Garmin civilian receivers by using some undocumented commands. See http://mywebpages.comcast.net/dmilbert/softs/g12r
retrorocket.o not found, launch anyway?
The site of the Commisioner of Irish Lights has a very good 101 on Differential GPS for those who are interested.
... in messing up Iranian GPS users (read: military). It would just make their movements more chaotic. Contrary to what you might think, a predictable enemy is far better than one who's actions defy reason. And all their missles have either inertial navigation, IR homing, or are ballistic so it's not like you're mucking up any precision guided equipment.
"Consensus" in science is _always_ a political construct.
For those who aren't familiar with WAAS, it's the Wide Area Augmentation System. It's like DGPS on speed. It's run by the FAA. They have a dozen receiving location scattered around the country, at precisely surveyed locations. They measure the difference between where the GPS satelite says they are, and where they actualy are, and then transmit that information to geostationary satelites, which then beam the info back to earth. In a nutshell you get 3m GPS accuracy.
:)
AFAIK there is no provision for reducing the accuracy of WAAS without just turning it off. The FCC would really like to use WAAS to enable planes to do instrument landings at airports without ILS. Of course the FAA can just turn it off anytime...
WAAS works great though. I've left my GPS on auto-detailed track mode, and I've inadvertantly created a highly accurate map of my campus just by walking around with my GPS in my pocket
-73, de n1ywb
www.n1ywb.com
Finally found the URL for the one utility I've used (Although haven't yet gotten my postprocessing code to work with it - The RINEX file is different enough from the ones recorded in CU's ECE 415 lab that the preprocessor chokes on it.)
n to nio/async/
http://artico.lma.fi.upm.es/numerico/miembros/a
retrorocket.o not found, launch anyway?
Yes, we all know how well European bureaucracies compete with American ingenuity... X.500 anyone?
The web, anyone?
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
- dj
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.
Having watched most of yesterdays parliamentary debate and spent some time reading the relevent resolutions of the security council it seems quite clear to me that 1441 was not intended to allow this sort of action.
The French and Russians insisted the phrase 'by any means necessary' be removed from 1441 before it was removed.
1441 requires the isssue to be brought back before the security council should Iraq fail to comply. This has not happened.
This war is not being prosecuted with the full backing of the United Nations. Just ask the Secretary General...
On the other hand...
Some of the argument made yesterday was particularly convincing. The point that has swung my opinion is that the war in Kosovo was undertaken illegally without UN support and nobody gives a sh*t because it was the right thing to do and has resulted in the situation in the former Yugoslavia measurably improving.
Invading Iraq is probably the right thing to do and backing of now is definately the wrong thing to do.
However many of us 'Brits' (puke) are extremely pis*ed of for a couple of reasons.
1. The majority of the British people stood up in protest (largest ever demonstrations in modern times) and were completely ignored. Not a good re-election strategy...
2. Resolution 242 still lies unenforced after something like 35 years. All this bleeding hearts guff about the plight of the Iraqi people sticks in my craw when nobody seems to give a fu*k about the plight of the Palestinians. Israel is in breach of UN resolutions and the Geneva convention and needs to be forced to comply one way or another.
Trust The Computer, The Computer is your friend.
Better the US send back the statue of liberty that the French gave them,
They don't appear to need it any more.
"Liberty" to the Bush administration just means the liberty to extend the holy USian empire by beating the shit out of whoever doesn't agree.
As heise already reported yesterday a US spokesman at the EU denied that the US would anything mentioned above.
See (lazy me, cut and paste from a google news post):
l ity.htm/ gps_pdd.htmS _SA_Event_QAs.pdf
http://www.igeb.gov/sa.shtml
http://www.navcen.uscg.gov/gps/selective_availabi
https://www.peterson.af.mil/GPS_Support/documents
http://www.ngs.noaa.gov/FGCS/info/sans_SA/docs/GP
In short, NO, they won't degrade GPS.
I dunno what's more disappointing, that some lamer submitted this to slashdot, or that more of you supposedly "Educated" geeks don't challenge the idea.
Erik
US-Army: We're terribly sorry, but unfortunately it has already been more than ten years since be bombed some brown people, so we will have to render our service unuseable for an unspecified amount of time.
Sorry, field-science, sorry, maritime travel and transportation, sorry you folks out there in the Sahara, Australian Outback or South-American rainforest. sorry Mercedes-Benz, sorry Motorola, sorry air-travel, you shouldn't be flying anyway during terror-level orange.
my
This will not effect the military P code
Until someone has the bright idea of blaming it for a "Friendly Fire" incident.
Of course, it would be much easier simply to blame the French, now it's become a habit.
--
Mr. Bush, Mr. Blair, in this post-911 era, think of the children - the Iraqi children. If you do not, then the terrorists have won.
Whilst I would love to be a pacifist, I accept the fact that war should always remain an option to be threatened and used as a last resort. I am not a secret admirer of Sadam, nor do would I in any way want to hinder the human rights of the Iraqi people - I'd probably be quite happy to support a military attempt to overthrow him - I just don't trust the motives behind what's about to happen. The official line is obviously a lie, and if we aren't being told the truth, it's a pretty safe assumption to say we therefore wouldn't like it if we did. US foreign policy is a complete disgrace, packed with double standards and has managed to amass such a level of distaste from the majority of the planet it has left pretty much the entire planet with a gut instinct to resist it at every opportunity. If anybody fancies some topical reading on the previous US policy of support for those who reported and provided proof of nuclear weapons existance in the middle east try Googling for Mordechai Vanunu
The Interagency GPS Executive Board (IGEB) was established in 1996 by a Presidential directive to manage the Global Positioning System (GPS) and its U.S. Government augmentations. The IGEB is a senior-level policy making body co-chaired by the Department of Defense and the Department of Transportation.
The IGEB have a statement on their website about Selective Availability.
Of course they could change this policy, but for the moment it looks like SA will not be turned on.
that the US turned off SA in the first place to neuter the Galileo project by reducing its perceived need.
Well, the second time the US turned SA off was for that reason.
This article is really amusing because of the fact that the government actually turned SA OFF for the last Gulf War, as there was a shortage of military GPS receivers and soldiers were ordering civilian units mail-order.
retrorocket.o not found, launch anyway?
A friend of mine is heavily involved in the EU satellite program (building them). Not only are we going to be getting non-US global positioning, we're also getting some other very clever satellites loaded with all sorts of clever gizmos which we're not allowed to talk about without our families being abducted in the middle of the night. Will help us spot the little errors that sometimes arise from US satellite intelligence e.g. "Oh look, we can see several hundred thousand Iraqi troops on your [Saudi Arabia] border - can we base our troops there to protect your oil fields population?
In the FAA air traffic simulator where I work, we have recently done studies preparing for what would happen if the GPS satellites were disabled (on purpose or jammed from a terrorist). NATCA (the controllers union) has developed procedures for what to do when this happens. Most aircraft would fall back to their backup navigation systems, assuming such systems would work on the route they were currently on. Less than 2% would even need attention, and it would be minor intrusion at that -- just enough to get then to where they can fly on their own. Even in the future, when some of the current systems are removed, it won't be much more of a problem.
;)
So you can feel just as safe flying as you currently do
----- I hate sigs.
Help me a bit here -- I believe GPS satellites are geosynchronous which would mean there are many "parked" over the US -- would it be possible to "fuzz up" the ones the Iraqis would use, but leave them at a higher level of accuracy in the US? I mean my friends who geocache will have a whole extra level of work if they decrease the accuracy to 100 meters... and I might take a wrong turn on the way to a restaurant. Better start protesting the war ;-)
I for one couldn't care less if hikers' GPS accuracy is reduced to 100m, but for the industry I work in (Precision Agriculture), this presents a huge problem. Many of our clients used DGPS back in the day, and in some areas where it is freely available (along the coast, mostly), still do. However, most do not. 3m was already bad enough, but 100m is a real problem. I'm sure there are other industries being affected by the use of SA as well.
I've built up so much character I have an alter-ego
I'm currently reading "The Measure of All Things/The Seven-Year Odyssey and Hidden Error That Transformed the World", by Ken Alder. It's about the effort during the French revolution to measure the distance from the pole to the equator as the basis for the standard meter. There are some interesting parallels with this GPS discussion, especially the parts about taking triangulations among the castles and forts on both sides of the French/Spanish frontier in the Pyrenees, while the battles were going on all around. Mechain, one of the astronomers, was able to determine some locations within one second of arc, or 100 feet -- in 1793! Who needs GPS?
People like you shouldn't be driving. The GPS is merely a navigational aid. It doesn't and never should replace KEEPING YOUR EYES ON THE GODDAMNED ROAD. You shouldn't need a GPS to tell you that you're on Foo Avenue - You should be looking at Foo Avenue and double checking that you're on Foo Avenue using these really cool devices called street signs.
retrorocket.o not found, launch anyway?
The inconvenience this might cause some people is worth it. Read some history and realize some of the inconvenience citizens had to tolerate in previous wars. This GPS thing is trite.
Admittedly, there IS some military data on the civilian frequency, but it's more than possible for the military to get a decent fix if the frequency that carries civilian data is jammed.
The P code is broadcast on two frequencies. This allows the receiver to measure and correct for ionospheric delay, but also allows the military to gain a fix even if one frequency is jammed, at a precision slightly better than that of the unjammed civilian code but worse than normal for military use.
Also, I've read that military receivers are much harder to jam. Most likely the P code is transmitted at higher power, and also military receivers can use a phased-array antenna and some DSP power to reject noise sources not in the direction of a satellite.
retrorocket.o not found, launch anyway?
You know, I hear a lot about U.N. Resolution 242 and its not being enforced. 242 is a chapter VI resolution (chapter VI of the U.N. charter). Resolution 242's "enforcement" is actually up to the parties involved in the dispute (Palestine and Israel). The member states have no obligation to enforce it.
The resolutions pertaining to Iraq are all (I think all) chapter VII resolutions. The member states are obliged to enforce these resolutions.
I didn't know this until a few months ago. I never understood why 242 was never complied with and thought it rather odd that they could get away with it. Now I understand. Chapter VI resolutions are simply the U.N.'s opinion on how a dispute should be settled amongst the parties (my understanding anyway).
BTW, I said 'Brit' out of habit, I guess. I noticed you put puke in parentheses after it. Is that bad? Should I have used Englishman or British or something else instead? Just wondering?
3cx.org - A truly bad website.
the same is true of the highway system and the internet, you know.
But it would also degrade performance in many other regions too. The thing is, the usefu; sateliites for 2D navigation are not the ones flying directly over Iraq, but the ones on the Iraq horizon. ( ideal GPS constellation is 3 satellites at low elevation 120 degrees apart, plus one over head). These satellites are also being useful to other navigators as well, so degrading individual satellites when they form the most useful constellation over Iraq would also fuck up someone navigating in the Mediterranean, or the Indian Ocean.
Donte Alistair Anderson Roberts - hi son!
Karma: Chameleon
SA was turned off less than three years ago.
Do you realize how long it takes from the initial design stages to general use for a commercial jetliner? A helluva lot longer than three years. Hell, I don't think a jetliner could even get FAA certification in three years from the first prototypes being built.
In short: AIRPLANES HAVE BACKUPS. GPS is currently considered to be the least reliable nav source, precisely because the military can kill the system or enable SA any time they want to. Pilots are required to be able to navigate without GPS and using their eyes only. If you can't navigate based on visual info alone, you don't get your license. Similarly, you don't get your IFR certification unless you can use all of the standard instrumentation that was in use long before GPS became common.
Also, most likely almost any aeronautical GPS will support some form of DGPS, which makes SA semi-irrelevant. As soon as SA turns on, it will be a matter of seconds before updated DGPS info starts coming through. (This is assuming that SA isn't turned on gradually. It most likely will be, in which case users of DGPS in one form or another won't notice a thing.) Locally, the Coast Guard broadcasts DGPS at VLF frequencies in localized areas, and modern Garmins support WAAS, which is a DGPS variant that uses non-military geostationary satellites to broadcast the corrections.
retrorocket.o not found, launch anyway?
According to this article, nothing needs to be done to the satellites at all. Jammers can be deployed to scramble civilian GPS signals over a localized area.
After all, when's the last time you've seen a GPS receiver with a dish antenna? Ground-based signals can logically affect them just as easily as sky-based.
All I want is a kind word, a warm bed and unlimited power.
Some Garmin receivers already support WAAS, which is a DGPS variant that uses data from geostationary satellites.
Kinda of hard to knock those out...
Also, terrestrial DGPS is not likely to be targeted by a missle for use in the USA.
DGPS isn't too expensive - Almost any civilian GPS receiver can apply the corrections if they are supplied, and receivers for the Coast Guard broadcasts are only $150-200 I believe. (And have been homebrewed for less.) If you have some form of wireless internet connection, do a search for dgps-ip - Essentially RTCM correction data that can be obtained by connecting to a port on a dgpsip server.
retrorocket.o not found, launch anyway?
This article 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.
One of the reasons they decided to turn off SA in the first place was that they had the capability to enable it regionally if needed IIRC.
So, couldn't they just dither the signal for Iraq/Middle East and leave everyone else with high accuracy?
Germany!
Where did they get the anthrax?
oh brave new world, that has such people in it!
From what I've heard, many ground-pounding grunts much prefer civilian gear to the military issue stuff their given by headquarters. Can't say I blame them either. Have you seen a Gov. Issue gps device, nearly the size of a small phonebook, vs. a commercially available one that fits in the palm of your hand. I was at REI yesterday, near a military base, when a small squad came in, and wanted to outfit their whole group. The REI salesman tells me that has been common during the military buildup. Many soldiers want sleeping bags, GPS, binoculars, etc. So, while I'm sure a ground unit is required to have a Goverment GPS device when he goes into battle, I wouldn't be too surprised if they carry around smaller, better, commercial devices, and prefer to use them. Degrading the signal used by those devices could possibly lead to serious errors and maybe even cost lives! Just my opinion, as I know little-to-nothing about military ops. -ABelenky17
It'll be interested to see if they actually turn SA back on or not. And if they do, will it be world-wide or can they really selectively turn regions off? Of course, as you want to hit 3+ satellites at a time, that will still effect a lot more that Iraqi. For example, right now Salman Pak (Iraqi Bio-war site) can see:
GPSBIIA-16(PRN01) GPSBIIA-25(PRN03) GPSBIIR-03(PRN11) GPSBIIR-06(PRN14) GPSBIIR-04(PRN20) GPSBIIA-12(PRN25)Turning SA on these 6 Satellites would screw up GPS in Iraqi - and a large portion of that hemisphere.
www.faa.gov has already got NOTAMs posted regarding inaccurate GPS readings and not to rely solely on GPS for IFR flight.
I personally believe that Iraq should be dealt with now rather than later when they may have acquired a lot more capacity for mass destruction. I understand that you may dissagree with war - that is another topic alltogether. Strictly speaking we were talking about the concept of America using the GPS systems to its advantage during a situation of war. To me this seems like a techologically sly and clever approach. Its not a matter of "hey, lets turn off GPS to piss off the world".
While I want to avoid a political discussion, it is worth noting that most of Europe (including the UK where I live) support the war. Admittedly there are variations in opinion, but I believe Germany and France are the only two main protesters. If we were to have a European GPS system, do you really believe during a war its owners would allow it to help Iraq?
I thought that most GPS systems used local transponders to get the fine-tuned location resolution. Or is that the old way?
I think we've pushed this "anyone can grow up to be president" thing too far.
While leaders in the government may not always do what we want them to do, we DO ultimatly have control via the Vote. If we REALLY want to, we can vote evey single person in office Out, and replace them with people more in line with our views. I keep trying but it's all the other idiots who keep getting in the way. =)
To Do: 1. Take over world 2. Pick up Milk and Bread on the way home
In war, the first casualty is always the truth.
Now correct me if I'm mistaken here, but wouldn't deliberately decreasing the accuracy of GPS signals essentially create a further handicap for this person who uses the equipment in his day to day life to function more like a "normal" person. Somehow that just seems wrong to me.
And on the up-side, it's great news for people who don't want the rental car companies tracking where they drive.
File under 'M' for 'Manic ranting'
IIRC, differential GPS is where you correct for clock error by using a fixed point with a very accurate latitude/longitude measurement as one of your "sattelites".
First of all, differential GPS operates with differences of a signal phases, not the timestamps.
Second, DGPS was the one and only high-precision ("tenths of millimeter") method available before Us army decided to remove all artificial noice from the signal in 2000. It is a static method though and requires two nodes to sit tight on their spots for at least few minutes to accumulate enough redundant data.
Thirdly, there is a kinetic methods that apply to a processing of noise GPS signals by moving objects. I dont remember all math behind it, but it works out into automatic cancellation of phase measurements error and gives a decent location and speed accuracy even with S/A on. Not suitable for high speed objects (such as missles), but more than enough for driving around.
3.243F6A8885A308D313
"Don't create competing products, because the USA already has made them". What happened to the capitalist ideals about competition in the market?
I went back and re-read 1441. It does say that (para. 11 and 12). However, it does not say the member states cannot enforce the resolutions as called on by resolution 678 which was recalled in 1441. Specifically - "Recalling that its resolution 678 (1990) authorized Member States to use all necessary means to uphold and implement its resolution 660 (1990) of 2 August 1990 and all relevant resolutions subsequent to resolution 660 (1990) and to restore international peace and security in the area. . .".
It seems pretty clear to me that this war is legal. I guess it all depends on how one interprets it?
Thanks for not jumping down my throat with a bunch of idiocy. A couple of ACs (go figure) below in this thread couldn't help themselves. Seriously... thanks.
3cx.org - A truly bad website.
I didn't know that about the chapters. Amazing how ill informed we all are about international politics even when said politics are a manifest risk to our own lives.
If 242 isn't chapter VII then it bloody ought to be. If Israels illegal occupation of Palestine had been ended in 1967 as Iraqs occupation of Kuwait was ended the WTC would probably still be standing.
It amazes me how the media portrays Israels attacks on civilian Palestinians.
If the 1st Battalion of the 227th Aviation Regiment were to fly their Apaches over residential, Catholic, areas of Belfast and start indescriminately firing UNGUIDED rockets in retaliation to Real IRA attrocities would it be reported in the same way?
I fuc*ing doubt it.
(BTW whoever it was that posted the link to http://www.cactus48.com/truth.html last week thank you. Always wondered what was going on there, although I fear I was happier in my ignorance, certainly less worried for my life.)
Al Queda has ably demonstrated the sort of resolve that won Scotland its independence
'for, as long as but a hundred of us remain alive, never will we on any conditions be brought under English rule. It is in truth not for glory, nor riches, nor honours that we are fighting, but for freedom -- for that alone, which no honest man gives up but with life itself.'
this is spirit that won the US its independence.
Whether we agree with their methods or not it is undeniable that they are willing to die for freedom from perceived oppresion.
(As a side note the techniques Bruce used during the Wars of Independence were brutal and definitely in contravention of the Geneva convention, I imagine it was little better during the American War of Independence.)
The cause of these attacks was Israel.
Israels flagrant disregard for international laws, treaties and opinion has placed our citizens in untimely graves. It is time Israel was put in its place. Israel is a child state and needs to be soundly spanked and sent to its room before its behaviour spirals completely out of control.
Don't get the impression that I condone terrorism, I do not (my sister lives in Belfast), however the pragmatist in me recognises that trying to swat thousands of flies (terrorists) is futile, far more effective to remove the steaming pile of dog sh*te (Israels illegal occupation of Palestine) that is attracting them.
As to the 'Brit' thing, I felt uncomfortable, as a Scot, lumping myself in with the English like that even though it was the appropriate way to phrase it.
A bit like Texans don't like to be lumped in with the rest of America. Or, God forbid, calling a Canadian an American....
Trust The Computer, The Computer is your friend.
The official sites to monitor if you're worried:
www.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 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.
but here in the UK the government may support America, but the majority of the UK population are against the war, as I believe is the case with Spain. Personally, I'd like to see someone tot up the various polls across Europe to try and give some idea of the general level of support across the continent.
we DO ultimatly have control via the Vote. ;-)
ahem... you seem to have messed up badly the last time
Except that he's more popular in France than ever, so why has he got to go again? You'd have a better case saying that Blair has got to go, given that he is going against the majority opinion of the british people ...
It also recalls that the ceasefire specified in 687 is conditional on Iraqi compliance with the disarmament program set out in 687.
So assuming that Iraq is not in compliance the original war is back on.
We don't need the security council to OK war in Iraq, technically we are still at war with Iraq and have been for 12 years.
There has been an extended ceasefire but 1441 makes it clear that that ceasefire will end if Iraq fails to use this 'final' opportunity to comply.
The second resolution authorising the use of force was never needed. However 1441 makes it plain that it is up to the security council to declare that Iraq is not in compliance.
However IANAL (yet) so YMMV.
What amazes me, in reference to 242, that this situation was allowed to continue for so long. According to 687 we should have gone back and destroyed Iraq's WMD program by force in 1998.
The UN has clearly (here and in Kosovo) been demonstrated to be toothless. It amazes me that the original Gulf war had UN backing not that this one doesn't.
Trust The Computer, The Computer is your friend.
in case the Euros don't oblige when we ask them to turn down the accuracy. Pass me that French fry.
to err is human, to forgive is divine, to forget is... umm...
Can we please have some grown-ups moderating?
I'm a bit fed-up with this childish name calling, by both Americans and Europeans. Time to grow up.
Yeah. I was spouting off one day about 242 when someone enlightened me.
If 242 isn't chapter VII then it bloody ought to be. If Israels illegal occupation of Palestine had been ended in 1967 as Iraqs occupation of Kuwait was ended the WTC would probably still be standing.. .
The cause of these attacks was Israel.
I agree with your sentiment on 242, but not the WTC. I used to think so, but upon further reading, I've since changed my mind. The Isreal-Palestine situation is one big fucking mess that never should have gotten this far out of control. However, no one, including the Muslim states and al Queda, gives a shit about the Palestines. It's simply a convenient banner for different groups (Muslim or not) to raise. If the Palestine conflict were resolved peacefully today (I mean Israelis and Palestines having pinics together), al Queda would still be blowing shit up. That's what they do. There is a great article about Palestine as symbol in the Jan/Feb 2003 Foriegn Affairs magazine (Page 19 - hey... I found the artcile).
A bit like Texans don't like to be lumped in with the rest of America. Or, God forbid, calling a Canadian an American....Hey... I'm a Texan and my last name is Canadian-French. Damn. Am I even American? HE HE HE
3cx.org - A truly bad website.
Now this is friggin cool. We apparently disagree on this war, but we're having an intelligent, CALM discussion about it. I wish this could happen a little more often. So many folks (particularly on slashdot) like to keep thing deep in the muck of stupidity and sometimes plain cruelness. Thank you. Not bad for 'Scot'!
(Don't take that the wrong way. I just had to use 'Scot' and couldn't think of a better way. It's 2am here in Japan and I'm BEAT!)
What amazes me, in reference to 242, that this situation was allowed to continue for so long. According to 687 we should have gone back and destroyed Iraq's WMD program by force in 1998.
The UN has clearly (here and in Kosovo) been demonstrated to be toothless. It amazes me that the original Gulf war had UN backing not that this one doesn't.
I couldn't agree more. If the U.N. AND their member states (inluding the U.S.) took care of business in the beginning, we wouldn't even be having this conversation. Don't forget the situation in N. Korea. The U.N. won't even touch it. That SUCKS. (I keep up with this situation daily. I live in Japan and am a consultant for United States Forces Japan.)
Your comments on 1441 are correct. But I think mine are too. So, we're just two shmucks talking about this. Imagine what a couple of International Law lawyers could do with it. I think the thing was written to appease too many damn factions. It says everything, yet it says nothing. I feel the U.S., Britian, and other supporting parties are justified... whether 'legally' or not. I've got a few friends over there and am very worried about them. I just hope that if any of them do bite it, they get it from a bullet and not VX, Anthrax, or [fill in Saddam's deadly nasty of choice].
Man it's late. I need to go to bed. I'm not sure what it does, but I've just marked you 'friend' in my slashdot preferences.
3cx.org - A truly bad website.
From New Scientist
Jammers can be deployed on mountaintops or tall antennas, but it is probably most economical to place them aboard aircraft. Langley thinks the US might also use "spoofing", in which fake signals fool the GPS receiver into thinking it is somewhere else.
Cool, make the enemy think they are about 500 miles east from where they really are.
Where the hell are we? This can't be right! According to this we are 300 miles out in the Gulf.
There is much cruelty in the universe, John.
Yeah, we seem to have the tour map.
Although GPS navication is supposed to be WAAS enabled for accuracy, I wonder how the change will affect others that use their GPSs for /G approaches to airports that do not have RAIM? 100M inaccuracy can be devistation on an approach in IFR conditions.
I personally have a Garmin 295 that I use however not for IFR approaches other than practice (in VFR conditions) just to fly the approach plates. Will this generate a NOTAM on the /G users out there or does the current system have the ability to disregard and use some sort of alternate navigation system?
'al Queda would still be blowing shit up'
You're not wrong there, interesting article.
Trouble is Palestine is such a popular and effective rallying call to fundamentalist causes because it is an outrage.
Really, once you have acquainted yourself with the facts of what is really going on in Palestine it is nearly impossible to be anything other than fu*king outraged.
I can see why Mulsim youths join Hamas and al Queda, I bloody would too!
Like I already said about firing rockets into Catholic Belfast, the PUBLIC behaviour of Israel is a disgrace, fu*k knows what they get up to behind closed doors.
As someone else suggested I googled 'vanunu' and I'm about ready to wet myself in fear.
The attitudes of some Orthodox Jews towards non-Jews make the Nazis look like the Boy Scouts. These are views that are popular in the Israeli military, and they are the lunatics with up to 500 nuclear warheads under their control.
What sort of Government extorts aid from the US by threatening its neighbours with nuclear weapons?
True al Queda will still be a pain in the arse once we kick Israel and all its illegal settlers out of Palestine but it will be a damn-sight smaller pain than it is now.
Without Palestine as a recruiting tool these organisations will have much more trouble recruiting young men willing to die for the cause.
BTW are you really a French-Canadian Texan?
That would be just far too bizarre a coincidence.
Trust The Computer, The Computer is your friend.
If you have one receiver in known coordinates and another at an unknown position (quite near the first one), you can 'detract' the error of the first receiver from the signal of the second. This way you get an error-free signal for the second receiver.
This is usually done in post-processing, but I have seen it done on the fly.
-jkk
When I was in the Air Force I was a weather guy. Well part of my job was to go with forward air controllers etc. to take weather observations and send them back to the people who put toghether briefings etc. Well the people who ran that part of the program wanted to put out a small kit with everything we needed in it. Since weather observations are useless if you don't know where you are they wanted to put a GPS unit in the kit. To save money they went with a civillian model. Nobody thought of the problem with theis till I was beta testing the unit and asked. I was told in a very formal way to shut the fuck up. AFAIK they are still using those units so there are going to be some very pissed of weather folks. Gawd I fell for them.
Cypherpunks: Civil Liberty Through Complex Mathematics. Those who live by the sword die by the arrow.
A regional blackout would hardly be less disruptive to civilians (in that region) than a degradation of precision.
Look, my point, which may have been lost (judging by the flamebait mods) in my frustration, is that civilians could be hurt if GPS were blacked out or degraded, and there is no reason to believe that precise GPS can significantly help Iraq. High-precision GPS was designed so our ICBMs (and now cruise missiles and smart bombs) could hit hardened targets like missile silos and command bunkers, or limit collateral damage. But (1) Iraq doesn't need any of those uses, either to defend itself against U.S. forces or to terrorize its civilian enemies, and (2) that kind of use requires guidance systems that Iraq doesn't have.
It's the irrationality of the fear that makes it paranoid. And it's the damage to civilian uses, some of which save lives, that makes the paranoia stupid.
"I've just marked you 'friend'"
Cool, I think I'll do the same.
I posted again above before I read this.
Kinda makes the conversation a bit disjointed, sorry.
I've never understood the need to be nasty in these discusions. The point is not to 'win' but to learn and to inform. I cannot force you to my point of view but I can give you the opportunity to learn things that change your mind.
I've always felt that if one is not willing to change ones opinion based on new information one should not bother taking part in debate.
Resolution 1441, cunningly constructed by all parties to be so ambiguous that neither side can be proven to be correct.
The 'allies' can attack Iraq and France can denounce them but neither side can be proven to be in the wrong. Kinda looks like a face saving excercise by France, saber, saber, rattle, rattle...
My thoughts are also with your friends and with anyone else out there reading this.
Hopefully casualties will be as small as last time or smaller (assuming friendly fire protocols have improved since last time, thats even worse than VX 'cos the families go through hell, on both sides.) and the people of Iraq will see a distinct improvement in their standard of living.
Legal or Illegal it doesn't matter its the right thing to do. Admittedly we are ignoring many other 'right things' for whatever reasons but that doesn't make this one less right.
Trust The Computer, The Computer is your friend.
at least we HAVE social welfare.
don't blame us that you spend 40% of your GNP on your army.
apart from the french and the germans, you had your chance for a coalition. but only if it was through the un, but if the us decides to do it their own way....
your freedom doesnt give you the freedom to invade whatever country you like.
i'd rather see saddam gone _with_ international support than with an us solo operation.
Privacy is terrorism.
Well, guys, I guess that either we're gonna have to stop and ask for directions again, or our dates will simply have to tolerate arriving late for awhile.
As of right now, my GPS receiver (in San Diego) shows that all of the GPS satellites it currently sees still have SA turned off. It's 1836Z on 3/19/03.
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?
putting the 'B' in LGBTQ+
You miss the point. When I wrote: >>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 wasn't criticizing Europe's social welfare programs. I was criticizing European countries for being essentially what we in the United States used to refer to as "Welfare Queens." In other words, Europe has been given a free ride for decades. Almost every other country in the world has to spend money on it's own defense. Western European countries have been the exception because the American taxpayers have done it for them. By the way, The United States spends less than five percent of it's Gross National Product on Defense, not 40. Germany and France spend less than 2 percent. The reason both countries can do that is the United States has spent it's own money defending Europe. A situation I really, really hope ends in the very near future. -rj
- dj
The early news discussions were predicting the war would cost about $200 billion. That's about $1000-2000 per American taxpayer. Of course, that doesn't count the cost of taking that money out of the civilian economy, which had better things to do with it. If they'd really wanted to take out Saddam because he was a mean nasty ugly guy, a Mossad hit squad could have probably done it for $5-10M, and the CIA could have probably done it for well under a billion, without the need to kill thousands or hundreds of thousands of Iraqi civilians or risk the lives of large numbers of US soldiers.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
"I know the card says the hole is a 104-yard par 3, but the GPS says I'm 523 yards away. Better pull out the driver to be safe."
"I have as much authority as the pope, I just
don't have as many people who believe it" - George Carlin
If you're trying to nuke civilians, sure, what's an extra 100 meters when you're trying to punish somebody for having Weapons of Mass Destruction. But the real concern with GPS accuracy has been pre-emptive ICBM strikes taking out missile silos, and there it matters quite a lot whether you're hitting the hardened silo on the lid or 100 meters away.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
Some of those systems were put in place to discourage development and widespread deployment of DGPS systems, and to retain some government centralized countrol of the technology. If there's ever a major ICBM attack on the US, you can bet that those things will be turned off right away, and any planes that were depending on them are going to have to land the old-fashioned way.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
Still, I have trouble thinking of time-critical GPS applications that couldn't be considered, if not purely military, at least dual-use (excepting rare events like saving trapped miners). For instance, I can see where the DOD might have an interest in halting the use of precision GPS for instrument approaches, even if the aircraft involved weren't always Iraqi Air Force. Do you have examples of purely civilian GPS applications that couldn't stand a few days or weeks delay, or be replaced by old-school methods?
Correct me if I'm wrong, but doesn't the parent paraphrase as: "If it's useful, and it's not ours, we have the right to blow it up."?
Since when does that sort of dangerous self-righteous neo-patriotic paranoia qualify as insightful?
This may be marked as flamebait, but it's worth the chance, I have Karma to burn anyway.
lysergically yours
Seems a few people here are more than a little gullible to believe this DoD spokesman at face value. More to the point than military PR, is whether or not they've degraded the signal in the past where & when it really counts.
"The first casualty of war is Truth"
There's no reason for the U.S. to degrade the signal out of fear of the Iraqis using it against allied forces. If there is any opposition, it isn't going to manifest itself in mobile battles where manuever is necessary, it'll be rooting out entrenched defenders of static positions.
100 meters is more than good enough for automotive navigation if you're paying attention to the road, so who cares about SA?
I've driven in New England without GPS assistance. There were a few times it might've been nice ("How many miles am I from Quincy Market now?"), but it's nothing 100 meters of error would've caused a problem with.
In short: If you're paying attention primarily to the road and your surroundings, 100 meters error won't hurt you at all.
retrorocket.o not found, launch anyway?
There's no difference between handheld civilian units and other civilian units. They all use the same signals, with the exception of survey-grade equipment which is not affected by SA to begin with. (That and civilian equipment which is receiving some form of DGPS correction data, whether through the Coast Guard's VLF transmitters in the US, WAAS from geostationary non-military satellites, or any other DGPS source such as dgpsip)
retrorocket.o not found, launch anyway?
Either way, it requires some sort of reference position in order to measure the error.
retrorocket.o not found, launch anyway?
This is fine for civilian use, but military units that wanted to radio home for the current reference offset would need to break radio silence.
One of the nicest things about GPS is that you *don't* have to have any other sort of telecom systems up and running -- GPS just works everywhere.
Bush is a jerk. If he thinks that GPS is going to help Iraqi troops worth a damn, he's in for a surprise. They can tell just fine when there's a plane overhead and shoot at it. In the meantime, it screws over civilians everywhere. I suppose doing otherwise would be to break Bush administration traditions -- screwing over civilians to benefit the military.
May we never see th
For what it's worth, we have been having trouble with our survey grade GPS the last couple of days. Tracking 9 satellites, we are having trouble obtaining "lock" and our vertical resolution is piss-poor....on the order of 0.1 to 0.5 foot where we usually get 0.02 to 0.03 foot with 9 satellites. The impending war and intentional signal degradation was the first thing that came to mind. Anyone else having similar trouble?
So will this make car navigation systems useless in cities where accuracy is needed? Hopefully we'll get the European GPS system sometime soon..
This comment does not represent the views or opinions of the user.
Nice knee-jerk there, dummy. Did you happen to notice you're replying to a Finnish person?
Stupid ass.
No, I didn't realize this until after I hit [Submit].
Next time I'll read more carefully, but I find this joke really funny anyway.
BTW, the only time you'll see my ass is when I'll poop on your face.
Votez ecolo : Chiez dans l'urne !
GPS may be jammable, but the JDAM and other GPS guided weapons have means for dealing with this. First, the GPS on the JDAM has an antenna that is designed to reject signals coming from the ground, as well as extensive anti-jamming electronics. Even if all of this fails though, the JDAM has an INS which will get it to a CEP of 30m. It's not the 18m or so with the GPS, but even that is the worst case scenario where you don't have GPS for the entire flight of the bomb. The more realistic case is that the jamming only affects the bomb after it gets low. In that case, with the INS only operating on its own for a few seconds, so the errors shouldn't accumulate too badly.
Anyone with the resources and the technology to deploy their own satellite positioning system is also in a position to defend their system from the US with economic sanctions or military force. Candidates include Japan, China, the EU, and Russia. I don't think the US could afford the repercussions of an overt strike to any of those nations.
So what happens to all those flash people going around with those gps powered devices which tell them where speed cameras are :-)
i predict many more speed camera tickets
Slashdot - The one stop shop for procrastination
ENIAC was developed to compute firing tables for the military. This doesn't mean that the primary purpose of computing equipment is for the military. I'm sure the economic impact of civilian computer use far outweighs that of military use. Computing has generally been repurposed for business and scientific needs.
TCP/IP was also developed to satisfy a requirement for the military, and it too has outlived its original purpose to serve a wider audience. Even if the military could they would never limit the use of TCP/IP because they would cripple the US economy. The benefits of limiting access to enemies would be outweighed by the instant revolution back home.
GPS may have been developed to guide cruise missiles, but it can do a lot more than that. The US military may currently have control over this system, but that won't necessarily last forever. One commercial dependence on GPS passes a critical point then the disadvantages of shutting down the system outweigh the advantages to our adversaries.
If Europe built its own GPS system, it would be interesting to have devices that use both the European and USian GPS systems and combined the results.
cpeterso
My view of the future would be one where the UN and the NATO have more power than now. a future where all countries, no exceptions, wouldonly use their army in a NATO context. this also counts for france in africa.
fighting unjustice is ok, but we all should agree on what that unjustice is. a dictator in africa deserves the same treatment as any other dictator.
countries should contribute a fair share in money and people for such an international army.
i know this doesn't solve the current crisis, but it's something for the future.
Privacy is terrorism.
We're never gunna solve this problem via slashdot. We need beer... and lots of it.
BTW are you really a French-Canadian Texan?That would be just far too bizarre a coincidence.
Yep. I'm, as Texans say, a transplant (not born there) and my father's side is French-Canadian from New England (great great ... grandad was from Canada).
3cx.org - A truly bad website.
I think the number of friendly fire incidents will be much less this time. Some of the newer 'battle management systems' (for lack of a better phrase) are simply amazing. They can track units' locations down to battalion level. It's amazing. (I actually admin some of these on occasion.)
Legal or Illegal it doesn't matter its the right thing to do. Admittedly we are ignoring many other 'right things' for whatever reasons but that doesn't make this one less right.Agreed. All countries in this world look after themselves the best. The other 'right things' in the world aren't getting the attention simply because nothing is in it for [fill in county of choice]. Perhaps someday, the Star Trek like utopia will come to pass.
3cx.org - A truly bad website.
So we've got the cheat codes?!
Thats pretty cool actually, maybe they'll find more tanks parked in squares.
Fine by me. Putains de merde.
-ccm
Too much Law; not enough Order.
eeeek, I should have mentioned, the higher CPU usage makes the map drawing slower on the
vista... thats the reason I usually turn it off. Also, 3-meter accuracy while moving
at 100km/h is pretty useless.
cheers.
``If a program can't rewrite its own code, what good is it?'' - Mel
So I assume that you would then agree that ALL countries should pay an equal share of the costs in these organizations?
The U.S. still pays for the defense of most of the Western European countries. The Europeans scoff at the amount of money we spend on defense. But they should look at themselves first. Do they realize how much of the American defense budget is directed at the defense of Western Europe?
The European contribution to their own defense is pathetic. It's time that the U.S. stops paying for the defense of these countries. They are all grown up and prosperous.
If the Europeans would simply pay a fair share of the costs of their own defense, the United States could then reduce its own defense spending and allocate that money to our own domestic needs.
If the United States had been able to spend all the money that we spent defending these European countries on our own domestic needs, we here in the U.S. would have a truly utopian society. We're talking on the scale of hudreds of trillions of dollars.
I'll make the analogy of a young adult still living at home with his parents. He wants to voice his own opinion and do things his own way. But he is not truly an adult until he moves out of his parents house, takes responsibiity for his own life and starts paying his own bills.
It's nice to see that the Europeans want to voice their own opinions on world events. It would be nicer still if they'd be willing to pay for their own defense.
-dj
- dj
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