In GPS why is it needed to convert Inertial system to the ECEF system (Earth centered earth fixed)? ?

Question

In GPS why is it needed to convert Inertial system to the ECEF system (Earth centered earth fixed)? ?

Answer 1

exactly: ecef maps naturally on to terrestrial coordinate systems. inertial does not.

Answer 2

People and other Earth-based things really have a hard time understand inertial coordinates. If you are at inertial coordinates (100, 134, 567), how far are you from New York?



But ECEF coordinates are easily converted to latitude & longitude.

Answer 3

The inertial coordinates for a static object would change as a function of time. So New York might be located at (100, 134, 567) at one instance in time, but at (-20, 30, 567) at another instance in time.