OBSERVABILITY ANALYSIS OF PIECE-WISE CONSTANT SYSTEMS .2. APPLICATION TO INERTIAL NAVIGATION IN-FLIGHT ALIGNMENT

The method of analyzing the observability of time-varying linear systems as piece-wise constant systems (PWCS) is applied to the analysis of in-flight alignment (IFA) of inertial navigation systems (INS) whose estimability is known to be enhanced by maneuvers. The validity of this approach to the analysis of IFA is proven. The analysis lays the theoretical background to, and clearly demonstrates the observability enhancement of IFA. The analytic conclusions are confirmed by covariance simulations. Although INS IFA was handled to various degrees in the past, a comprehensive control theoretic approach to the problem is introduced in this work for the first time. The analysis yields interesting practical conclusions and a procedure hitherto unknown.