Adaptive Target Tracking of Underwater Maneuvering Targets Using Passive Measurements

This report examines the problem of adaptively tracking a maneuvering target in two dimensional space using passive time delay measurements. The target is free to maneuver in velocity and to make depth changes at times unknown to the observer. Tracking is accomplished by using the basic polar model of target and observer motion previously developed, and included in this report for the convenience of the reader. However, the important distinction is that now a nonlinear prefilter has been added to the tracking system. This leads to two major benefits: the first, is that the need for extended Kalman filters is completely eliminated which gives the tracking system a much a larger degree of robustness than it previously had. The second benefit is a decoupling of the depth estimator from the polar range estimator, which considerably reduces the computational level of the adaptive tracking system. (Author)