While I understand the general concept of how GPS locating works (your device captures timestamps from 3-or-more various global positioning satellites, then calculates where in the world you are), I've always been curious about how accurrate they can actually be.
If you are going to calculate, down to sub-centimeter distances, where your device is, wouldn't you need to know the EXACT location of these satellites, down to the sub-centimeter level of its altitude/lattitude/longitude? Like, if one of the satellites drifts slightly out of place from where they think it is, couldn't that throw off all calculations?
I always thought GPS could only determine your location down to roughly a 5-meter range because that's as good a guess that anyone could make as to where in orbit they are. No?
All I can think of is that maybe there are ground stations that the satellites use to find THEIR locations in orbit, kind of a GPS-locating that the orbiting satellites use... but I haven't really heard of any of that. Anyone know anything about this? Just curious.