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."

Good stuff

[sokkelih]

This means that my grand dad can get lost in forrest while picking up mushrooms. I can get my legacy faster. :)

Re:Sanity checks..

[zCyl]

Which sane person would rely on GPS data for something even as trivial as navigation?

Have you tried navigating by the stars during the day lately? The blue room can be a big scary place.

In other news today...

[Noryungi]

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.

So the US sold the GPS equipment as well?

[Snaller]

I mean I know they sold them Anthrax, but didn't know about the GPS euipment ;)

Re:A question

[Ryan Amos]

First guess says you need satellite access codes. Second guess says the stream is probably VERY well encrypted. Third guess says that if you access the military channels without permission, you'll have men in black helicopters doing fastrope descents on your place of residence within a few minutes (it's GPS, so they already know where you are.) Though I could just be blowing this out my ass, who knows.

Re:Ouch

[Anonymous Coward]

imagine it thinking I'm a block away from where I really am.

Imagine, you could end up fucking a girl at the right address but on the wrong street, thinking it was your girlfriend.

Re:Good stuff

[ramzak2k]

hey shonny, i heard ya .. haw haw.
I am sending your grandma to get the mushrooms today.

Re:Gelileo

[kir]

No doubt that Europe some day will be the next on the US' countries-to-invade-because-god-told-us-so list.

I am eagerly awaiting that day. Then I can get free oil and beer!

onstar?

[Joe the Lesser]

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.'

Re:This was *exactly* why we here in Europe...

[YE]

It's not been scratched, it's waiting for a committee to decide when another committee will meet to reach an agreement on when to plan the first meeting of the EGSC (European Galileo Scheduling Commission).

this is reliable info

[commodoresloat]

Dude, it's from the head of a German Autoclub. The head! Not some secretary or anything.

Re:It is worth noting that this is a localised eff

[Richard W.M. Jones]

As the GPS network can be degraded or upgraded region by region.

It's OK, I've got the multi-region hack for my GPS decoder ...

Rich.

But

[secondsun]

All you need is the nuclear missile and the 100m doesn't matter anymore.

I love Bush

[Anonymous Coward]

But this being slashdot, I guess most here prefer Dick and Colin.

Re:So the US sold the GPS equipment as well?

[mgblst]

A joke in The Australian newspaper the other day:

Reporter: So how do you know that the Iraqis have Weapons of Mass Destruction.

American: We kept the reciepts!

boom boom.

Re:In other news today...

[j7953]

This did actually happen in Germany: some idiot drove his car into a river because the navigation system displayed a bridge, but actually there was only a ferry.

See pictures of his car here [freefall.de] (scroll down).

The last paragraph of the text says: "Please note: A GPS system cannot be a substitute for the driver's attention! In december 1998, a driver trusted his navigation system which suggested to continue driving straight ahead. A few seconds later, his car got wet because his road database didn't know anything about the ferry across the Havel (a river near Berlin). This is not a joke! The TV channel RTL had a report."

Re:this is reliable info

[realnowhereman]

Of course - I forgot that the American chiefs of staff have a strict policy of inform and consult with the German auto club.

Re:Simply does not matter

[Anonymous Coward]

Yep I can see it now...

"Honey, it told me to turn left here. We're on 4th St. We are supposed to be on 5th St. Damn the government. DAMN THEM FOR TURNING ON S/A!!!"

"Didn't you see the sign?"

"I was on the phone. Besides, that SUV blocked my view."

Re:Sanity checks..

[chiph]

In-car navigation system: $1800
Handheld GPS: $200
Paper map: $5

Again, the dead-tree edition proves to have hidden advantages, such as never needing batteries, not breaking when you drop it, and having consistent results during wartime.

Chip H.

Re:onstar?

[Lxy]

I've got a friend in MN. One winter night he and his buddies decided to have some fun with Onstar. Knowing that the call center is somewhere in Florida or California, they drove onto Mille Lacs lake (a very huge lake for those of you who don't know, it's larger than most counties). They called up Onstar to ask for directions:

Onstar: "hello?"

Friend: "We're lost. Can you help us find our way back?"

O: "Sure, hold on. Hmm.. this must not be working right. It says you're in the middle of a lake!"

F: "I know. We need to find our way back to shore"

O: "????"

F: "We're in Minnesota. There's ice on our lakes here"

O: "???? How are you in the middle of a lake?"

F: "We drove out on the ice"

O: "Why would you do that?"

F: "Ice fishing"

O: "?????"

F: "Can you direct us to the nearest landing?"

O: "Umm.. hang on a second. I need to get my supervisor."

Re:GPS and boating.

[CaseyB]

I should have known some smarmy blow-boater would reply.

The only smarmy crap here is your my-kinda-boat-is-better-than-yours shit.

turning S/A back on will result in deaths and injuries.

Ever heard of flats fishing? Ever seen someone fishing in freshwater coves that have no navigation aids?

And if you can't find the right spot to fish, you'll DIE.

Ever seen someone navigating narrow, unmarked rivers?

And if you can't keep your boat between the banks by using only your GPS, you're going to DIE.

Do you think that the navigational aids faeries put up obstruction markings while you sleep?

Whereas the GPS faeries DO put up obstruction markings while you sleep.

Re:This was *exactly* why we here in Europe...

[linzeal]

But we are your friends, and we like your freedom fries, mmmmmmm freedom fries.

Spoof?

[Fishstick]

From New Scientist [newscientist.com]

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.

Golf Scores to Skyrocket!

[scheming daemons]

Look for a large increase in golf scores, as the many courses that use GPS will be effected.

"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."