In article ,
Tim wrote:
On Thu, 23 Sep 2004 15:57:55 +0000, Peter Masson wrote:

(Can GPS identify which line the train is on if adjoining
platforms are different lengths?)

Not with any certainty.

Of course, what happens if the Pentagon decided to turn off GPS for
civilian use without warning (which they've always stated they have the
right to do)?

Galileo. And, indeed, Glonass (which we have now - and most receivers are
dual GPS/Glonass)

Or worse, they have a war and introduce deliberate errors into the system
designed to confuse the enemy?

Galileo. And, indeed, Glonass.

I can see it now on the 9:24 from Tonbridge: "We will shortly be arriving
at Copenhagen, please mind the step"

Galileo. And, indeed, Glonass.

I know that Europe is going to deploy it's own GPS sats, but I don't know
when that will be.

Galileo, not GPS. A much better system (it'll have to be if it's to do a
fraction of what they're wanting it to do). The programme is being pushed
ahead hard and should be delivering in the next 3-5 years (depends how
fast the constellation goes up, which in turn depends on who'll be
launching). In the meantime there's Glonass, which the Pentagon certainly
doesn't have a veto over.

--
Andy Breen ~ Interplanetary Scintillation Research Group
http://users.aber.ac.uk/azb/
"Time has stopped, says the Black Lion clock
and eternity has begun" (Dylan Thomas)