"Pathfinders" Take Shape For Galileo, Europe's GPS

oliderid sends along a BBC report on progress toward Europe's home-grown GPS system. The Galileo concept will get an initial test via four "pathfinder" satellites that will be the first in the Galileo constellation. Galileo is intended to be complementary with the US GPS system — when all 30 Galileo birds are flying, a receiver with both GS and Galileo capability should enjoy 1-meter positional accuracy, vs. the several meters available through GPS alone, according to the article. There's a video tour of the facility where the pathfinders are being built. "After all the wrangling, the delays, and the furor over cost, Europe's version of GPS is finally starting to take shape. Due for launch in pairs in late 2010 and early 2011, the 'pathfinders' will form a mini-constellation in the sky. They will transmit the navigation signals that demonstrate the European system can become a reality."

Comments

general relativity at work

[bcrowell]

What I think is really cool about GPS is that without Einstein's theory of general relativity, it wouldn't work. For example, the atomic clocks aboard the satellites run faster because they're higher up in the Earth's gravitational field, and when you're higher in a gravitational field, time flows more quickly. If they didn't compensate for this effect (and a bunch of others), the system wouldn't work at all. Of course you can still find kooks on the internet who think that relativity is all wrong, and have mathematical proofs to that effect. I wonder if those people refrain from using GPS?

Re:general relativity at work

[dkf]

I'm struggling to think of a positioning system design that would require GR/SR to work rather than time of flight... I think it would have to be an active transponder system, or some kind of weird gravity wave detector? It would be interesting.

If we ever need accurate positioning around a black hole, we can at least know that slashdot will be able to tell us how!

And people call us useless! Hah!

Re:The EU system won't get used

[Anonymous Coward]

GPS is so standard now, and it is bugfree. It's hard to imagine anyone switching.

Yeah, "complementary" is a long word, isn't it? I wonder what it means.

Re:EU Vehicle Tracking Plan

[thogard]

SA was a hack on the early systems and the newest sats don't have that ability at all. The SA adjuster on older sats is a motor driven thing and it has been broken on several sats since before SA was turned off. The new sats have spot beams which can be used to turn off GPS (and may have the ability to introduce random jitter in the outbound signals) in part of the world but the USAF has local GPS jamming that works far better. The problem with turning on SA or blocking GPS in a local area is that having GPS work properly is more useful than having it broken since the US is in a better position to use the technology in a hostile location than the locals are at using it to fight back.