GPS (not a/c question!)
Trusting that some GPS savvy person is to hand ... a friend wonders about her car's Sat-Nav. "It's tells me the speed I'm doing but when I'm going up a steep hill - how doe sit work out the speed?"
My reply was, "The distance between you and the satellites changes so little (relatively) that it makes no difference. Also, the device will be triangulating with three or more signals."
Am I on the right line?
Cheers.
--------------------
"I tell you, we are here on Earth to fart around, and don't let anybody tell you any different." Kurt Vonnegut, Jr.