Design of leveling loop for marine navigation system

The problem of designing a leveling loop for a marine navigation system (MNS) is considered. The suggested leveling loop is based on H_∞-optimal state estimation which ensures, via an appropriate frequency-dependent weight on the estimation error, a prescribed bandwidth of the loop, to track ship maneuvers. The H_∞-optimal estimation-based loop is compared with a corresponding loop which is designed by applying the Kalman filter. The tradeoff between the requirement of minimum level-error variance and the goal of achieving the desired loop bandwidth is discussed