Comments and further results on "Observability of an Integrated GPS/INS during Maneuvers

The above-mentioned paper presented an observability analysis of GPS/INS during maneuvers based on a perturbation model. This note is on several issues regarding two theorems (Theorem 4 and Theorem 5) for the time-varying cases in. Specifically, this note points out and corrects several errors in the proof of Theorem 4, and extends Theorem 5 to yield full observability.