I THINK the GPS is only used for the inital setup -- I don't think if you put the telescope in a truck it would be able to keep aligning and realigning. But let's assume that was true.

If the Earth were moving unpredictably -- how does GPS figure that out? It uses triangulation -- and makes the same assumptions that the 'scope does.

Let's say the Earth magically halted suddenly. GPS will triangulate where you are in relation to the satellites -- but the way the GPS receiver calculates where you are on Earth would be completely wrong. Likewise, the telescope would think it was rapidly moving, at thousands of miles per hour, because the Earth suddenly stopped. Not to mention other catastrophic effects of that, anyway...

Same thing goes for flips or other unpredictable motions. There just isn't any math for predicting the unpredictable, and that's all these 'scopes do is math.

And, also, older telescopes, not using the nifty GPS tech, would certainly have no minute-by-minute information. They work on plain old gears and math. Permanently mounted telescopes, likewise, would fail altogether.