Why do we need satellite navigation? I mean don't they KNOW where the satellites are already?

No, they rotate in orbit... sometimes they get knocked out or something else happens and they drop off.|||NASA has lost a lot of things in the past, including the sanity of their astronaut, Lisa Nowak.|||Yes, but they use reverse psychology to keep track of you.|||Yeah, except for the ones that get launched at night. They're kinda hard to keep track of.|||Perhaps not, it is dark up there!|||now thats a spaced out question