Re INS/GPS
Yes of course: I did mean INS; Inertial Navigation System.
And yes I realize that I should have said the poles along the axis of the earth's rotation. At these poles there's a rotation at a fixed point (in theory). And the pole Star is centrally overhead for alignment
Re GPS: Quite correct the Satellites are not geosynchronous.
As an aside, I do not think the earth's speed of rotation is constant (irrespective of Latitude) - Any stellarium users out there (you can see variations in the earths speed of rotation on screen)
I had no idea that such a "simple" question could yield such complex answers and analysis.
Thanks for all the corrections.
CAT III