Comparison of Error Propagation in Local-Level and Space-Stable Inertial Systems

A comparison of the error propagation in a local-level reference frame is derived for two inertial navigation systems; one has a local-level configuration, and the other has a space-stable configuration. The error propagation is shown to be equivalent for the two cases considered. This equivalence is demonstrated by starting with the error propagation equations for the space-stable system and transforming them to a local-level reference frame. The transformed equations are then compared with the classical local-level error equations, and the equivalence is noted. The specific implementation used in each case considers velocity damping but not altitude damping.