Galileo

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The Amerikans can control individual satellites, it's true. So, an entire half of the world could have "degraded" performance. By degraded, I'm talking about precision, not "availability". Availability referrs to the the actual ability to receive the signal. It's in our own best interest to always have availability, everywhere in the world.

Yup. Even over China. And those Russkies, too.

There's something like 24 satellites, orbiting at 20,000miles. The system was designed so that, no matter where in the world you were at sea, you had line-of-sight to at least 3 satellites. Over the US and Europe, actual land features were taken into account, so you didn't get in the Grand Canyon or the Alps, and find you were having problems. There are still some valleys and holes in the ground, where you can only pickup 1 or 2 satellites. This is what that article was referring to.

In a plane, however, everything changes. Over the US, at 1,000 feet above ground, you can normally recieve 5 satellites. At 30k feet, it jumps to 8 or 9. There was someone back in the late 90's that actually went through, and figured out exactly where in the world you could pickup the most satellites at one time. It was up toward Greenland and Iceland, but I don't remember where exactly.

On a related side note, I heard those GPS jammers the Iraqis had were completely in-effective. IN PART, due to the high-precision timing that is encrypted from the satellites.

 

Well, of course do I read my sources carefully. I just use them to get my point through, not also pre-empting you from stating yours. Just needed it to support my other quote, that 50 meters are actually the margin of error. Under what circumstances exactly and if always, is a different matter of course.

The related point, but I am actually to lazy to confirm that myself or google a source is, that I've overheard somewhere, that Airplanes have a collision-preventing-device on board, based on GPS, which steers the planes automaticly, (I believe, does not only start blinking) away from eachother, if two planes get too close to eachother, on the tight airspace nowadays. I wonder what error margin they put in for this device. I think it may be 50 meters, at least in some places and it starts too change course at about 150 m (margin of error already added). Again, I'm not sure about that, some aviatic freak may know exactly ?

More unrelated, my understanding is, that GPS and Galileo in fact are planned to work in tandem, which would highten accuracy anyway.

Well, Iceland is a former Danish colony and the people are mostly from Scandinavian and Irish ancestry and the people are counted as Scandinavian and they have those gory stories about women having some strange ideas and sending their men to bloodbaths, but as I said Scandinavia, I've meant that part in the north of Europe, not in the north of the Atlantic. That in Greenland and surroundings the recieving may be best wouldn't surprise me much, as it is, I think, home one of the most important metrological stations in the world because of it's geographical position. (And incidently, Iceland would also lay on that tight sceduled aviatic-route). That Greenland is the bright spot, wouldn't automaticly mean, that northern Europe isn't the dark spot. Even more so if one presumes that Northern-America is shined on.

(By the way, what's the shape of the earth ? Geoid ! Muahahahaha. I know lousy joke, but the term itself is lousy. Potatoid would be better.)

Actually nothing. Details about when and how jamming it, may even be part of the EU-US agreement. On a lighter side, in the case of the case, we could then complain about those Bruxelles dorks and don't have to focus on Washington, wouldn't that be better for all ?

Oh, actually, I'm quite convinced that Galileo is worth to push through completly on its own merit, without argueing about GPS. GPS came only up, as it was argued, that GPS is there and free for all, so why bother. Galileo will offer the same service (and some service for pay), but it's actually about good spend welfare and building up an infrastructure in an upcoming market and try to get a share. That's in itself is good enough for me, that I think it would be good if we'd participate over the space-program or even bilateral-specific.