Position and Velocity Navigation Filters for Marine Vehicles

This paper presents the design and performance evaluation of two globally stable time varying kinematic Navigation Kalman filters to estimate linear motion quantities, in three dimensions, with application to underwater vehicles. The proposed technique is based on the linear time invariant Kalman filter steady state solution and employs frequency weights to explicitly achieve adequate wave disturbance rejection and attenuation of the noise of the sensors on the state estimates. In the first case study a Navigation filter is designed for the estimation of unknown constant ocean currents, linear position, and inertial velocity of an underwater vehicle with respect to a fixed point in the mission scenario. In the second case the proposed solution also addresses the estimation of the acceleration of gravity. The theoretical background is briefly introduced and simulation results are offered that illustrate the achievable performance in the presence of extreme environmental disturbances and realistic noise of the sensors.