Bush to consider shutting down GPS in extreme emergency

[Mxsmanic]

Not because the EU particularly WANTS to spend a few billion dollars duplicating a US system.

But because the EU no longer trusts the USA.

Or because the EU wants to (try to) prove that it still amounts to something.

 

[Mxsmanic]

The EU trusted the EU far more than the DoD; and that was BEFORE our current Administration took over...

I'm not so sure. If Europeans trust each other so much, why aren't they one country?

 

[Fred]

I'm not so sure. If Europeans trust each other so much, why aren't they one country?

And if Americans trusted each other more they would not be so certainly divided red and blue.

 

[Steven Shelikoff]

A jammer won't disable GPS over a 'region' nor, as suggested by the OP, will it 'shut down GPS'.

Depends on how big a region you want, how high you fly the jammer, how many of them you put up, etc. You can jam just about any "region" you want with the right set of tools. True, jamming won't shut down GPS. But that's only semantics since it will make it unusable for the vast majority of users in the jammed region, effectively shutting it down for them.

Steve

 

[Vincent van der Laan]

Or because the EU wants to (try to) prove that it still amounts to something.

Our economy is far stronger and look at the weak dollar!

 

[Mxsmanic]

Our economy is far stronger ...

But by luck, rather than by design.

 

[Mxsmanic]

And if Americans trusted each other more they would not be so certainly divided red and blue.

Americans are divided because they have sacrificed rational thought for star appeal. This will come back to haunt them.

 

[Tom (archive)]

But at what cost?

Garmin 2610 = $700, paper map = $.50

 

[Juergen Nieveler]

I'm not so sure. If Europeans trust each other so much, why aren't they one country?

Guess what's currently happening. You can't just say "From now on we're one country", it's always a long process. It even was for the USA, and they had the advantage of starting out mostly with empty space, whereas countries in Europe have up to 3000 years of history of not trusting each other.

Care to look up the history of the US Civil War? ;-)

Juergen Nieveler

 

[Juergen Nieveler]

That leaves only a few hundred zillion square kilometres of unrestricted, unmarked ocean to navigate.

So? Captains have learned to do that centuries ago. The biggest hazard to shipping isn't "Getting lost", it's "Hitting stuff that isn't on the map".

The Titanic would have been lost even if they'd had GPS.

Juergen Nieveler

 

[Juergen Nieveler]

You have to survey to produce a map.

Yes, but surveying isn't only done to produce maps - indeed most of the surveying is done to build stuff like roads, bridges and buildings.

And it's more accurate.

Not necessarily. A good surveyor can work without GPS just as easily - or how would you explain that people where able to build bridges and roads long before GPS was invented? Not to mention that some of the most difficult building projects were done where no GPS is available:
Below ground. Think the channel tunnel builders used GPS to build their tunnels?

Yes. Especially in a war zone. Getting lost is a serious problem in wartime.

Which is why the US Army would want civilian GPS shut down in time of war: They want to be the only ones with the advantages of GPS. I doubt the Pentagon would shed a tear over enemy units getting lost - and they're the owners of GPS, so their rules apply.

It doesn't matter, since U.S. people are demanding it, too.

Question is: Will the Pentagon listen? Doubtfull, at best.

So would GPS.

So you won't pay your GPS bill next month? The Pentagon will be trembling in fear.

Juergen Nieveler

 

[Juergen Nieveler]

And not even that, if you have plenty of time to make observations.

But if you have plenty of time anyway, you can just as well do it without GPS.

Juergen Nieveler

 

[Juergen Nieveler]

No, the real question is cost effectiveness. It makes no difference that something can be done if it's too expensive to be practical.

But that's not a problem for the Pentagon, is it?

No, it's not, because there's no easy way to synchronize it with other clocks.

But that's not a problem for the Pentagon, is it?

Juergen Nieveler

 

[Juergen Nieveler]

A quick google search reveals that they orbit at about 19,000 kilometers in a 12 hour orbit. That places them 3 radii from the center of the planet or 2 radii above it's surface. A little bit of quick geometry would clearly support the claim above, that they are "visible" over most of the hemisphere they are above. That varies of course since they are by no means in equatorial orbits

But for GPS to work, you need at least 3 satelites. And you can only get a working solution in the area where the 3 circles cast by each satelite overlap.

So yes, each satelite itself can be seen from half the planet - but the area in which they form an effective navigation system still isn't nearly a whole hemisphere, depending on the orbits of the satelites.

Juergen Nieveler

 

[Juergen Nieveler]

Terrorism happen all over the world and many live are lost everyday. Can you demonstrate how terrorist might make use of GPS signal during an attack and how removal of those signal after the attack has started, would change its outcome, if at all?

Can you proof that not a single life would be safed by NOT shutting GPS down, just to keep it running for some people who didn't pay a dime for that service?

Juergen Nieveler

 

[Juergen Nieveler]

What percentage of them are using GPS?

Globally? Less than 1%, I'd say.

The only problem is that there are thousands of other applications that use GPS, and guiding a missile is a trivially insignificant application in comparison.

Tough luck - the Pentagon owns the system and pays for it, they decide what happens with it.

And if aircraft have contingency plans for flying without GPS, why wouldn't missiles have the same?

Nobody claims that missiles wouldn't work anymore. But the Pentagon can shut down GPS any time they like, for every reason they can think of - you can't stop them from doing it, nor can anybody else except the President of the USA - he's the only person in the chain of command that ranks higher than the Secretary of Defense, who`s the owner of GPS.

Juergen Nieveler

 

[Juergen Nieveler]

You can use GPS to measure it.

No, because at that time you won't have a DGPS station up - that's what you are doing at that point, remember?

Of course, there are enough fixed reference points where you could set up the DGPS, so that's not an issue in the real world.

In time, yes.

And the problem is?

I don't think it would be much of a problem for surveyors. But they aren't the only users of GPS.

So we actually agree on this

Juergen Nieveler

 

[Juergen Nieveler]

And my point is at what cost?

More expensive than nothing, of course - GPS is available for free, so every alternative will be more expensive.

Juergen Nieveler

 

[Juergen Nieveler]

The same can be said of electricity. And yet doing without electricity would be a worldwide catastrophe.

You get electricity for free? Where?

A better example would be your email account: You're using Hotmail, which is a free service. If Microsoft decides to shut down Hotmail, you'll have to look for another mailbox. You can't force Microsoft to continue providing a free service to you, regardless of how important your mailbox might be to you.

Juergen Nieveler

 

[Juergen Nieveler]

The quintessence of GPS is accurate timekeeping, which is essential to accurate navigation. That is just as true now as it was centuries ago when marine navigation drove the development of accurate chronometers.

Yes, but timekeeping wasn't the reason why GPS was built. If it had just been a question of keeping clocks synchronized, there would have been easier ways to do that.

Juergen Nieveler