Posterior Cramér-Rao bounds analysis for INS/USBL navigation systems

This paper presents a performance analysis for Ultra-Short Base Line (USBL) aided Inertial Navigation Systems (INS) resorting to lower bounds for the covariance of the estimators based on the Posterior Cramér-Rao Bounds (PCRB) theory. In this framework, the vehicle interrogates acoustic transponders located in known positions of the mission area. Two distinct design methodologies are presented: one that estimates essentially the position of the origin of the Body attached coordinate frame with respect to Earth, and the latter that tracks the position of the transponders in the Body-fixed coordinate frame. The performance of both systems is compared in simulation leading to the conclusion that it is equivalent. Their efficiency is also assessed in simulation by verifying that both systems perform near the PCRB.