Slashdot Mirror
Galileo: Europe's Version of GPS Reaches Key Phase
another random user sends this quote from the BBC:
"The third and fourth spacecraft in Europe's satellite navigation system have gone into orbit. The pair were launched on a Russian Soyuz rocket from French Guiana. It is an important milestone for the multi-billion-euro project to create a European version of the U.S. Global Positioning System. With four satellites now in orbit — the first and second spacecraft were launched in 2011 — it becomes possible to test Galileo end-to-end. That is because a minimum of four satellites are required in the sky for a smartphone or vehicle to use their signals to calculate a positional fix."
Galileo is nothing but a multi-billion dollar pissing contest with the US to say "look at me, I can make my own GPS". When the continent is neck deep in an economic crisis that is miring millions of people and putting nation states on the verge of collapse, their priorities are seriously misplaced.
Seriously, there is no real benefit to this other than vanity and snubbing their noses at the United States. This has seriously got to be one of the most foolish economic decisions they have made in decades. Might as well spend billions of dollars making your own version of the Internet for the same reasons and results.
"Farm machinery has grown in size and complexity over the last couple of decades."
Why? Are you saying it's because GPS was there? That's pretty stupid. It might be true, but it's pretty stupid.
"GPS is now REQUIRED for many machines."
Then get different machines. I still don't give a damn. You can put up some reflectors at the edge of your field and use a goddamned laser. There are about 100 ways to get around this "requirement".
And you can think I'm trying to be a douchebag all you like. What I'm doing is giving my honest opinion. If you don't like it, that's fine; ignore it. But I *DO* know something about it. I live in an area that is mostly rural, and mostly farms (where the terrain is not prohibitive, that is). So FOAD yourself.
"Simple geometry states you need three satellites for an accurate 2D fix, and four satellites for a 3D fix, not whether you have access to the encrypted P(Y) code."
Um... Duh... simple geometry doesn't apply here, because these are TRANSMITTERS THAT KNOW THEIR OWN LOCATION IN SPACE AND TIME.
Get that?
I am replying to you, but this is really aimed at these other dimbulbs who are arguing with me.
Listen up, folks. I don't claim to be the brightest bulb in the universe myself, but I do pretty good and I remember my recent history, which many of you seem to have (forgotten; never learned; didn't pay attention... pick your answer).
GPS has been around for a long time. But it was only pretty recently that we civilians learned about it, and it became something useful. Why? Well, that's a story.
Much of the GPS signals are encrypted, for use by the military. The high-precision part. When people saw potential for civilian use, they were somewhat dismayed, because the un-encrypted part of the signal was pretty inaccurate. Your location could only be found within a few tens of meters. Not good enough.
So a few electronics companies -- at about the same time -- came up with the idea of using a FOURTH satellite to correct the sloppy timing they got from the USUAL 3, used by the military.
And thus practical, consumer GPS was born.
But make no mistake: GPS was designed to work -- does work, still works very well -- for the military with only 3 sats visible. That is the way it was designed, that is the way it works.
So stop giving me all your theory about how it "needs" 4. You are just plain wrong.
"... we can say with confidence that when we solve the navigation equations to find an intersection, this solution gives us the position of the receiver along with accurate time thereby eliminating the need for a very large, expensive, and power hungry clock. The very accurately computed time is unused in many GPS applications, which use only the location."
Note the phrase: "computed time". Not measured time.
Bozo.
It doesn't work by "triangulation", dimbulb.
Jesus, spare me.
"With 3 satellites there are 2 possible solutions to the equations. Since we know we are on earth and not in space one solution can be discarded. So in theory 4 satellites are required in practice not."
I mentioned this myself elsewhere. But as you of course know, one of those solutions is clearly nonsense, so there is no ambiguity.