A Multiple Model Adaptive Wave Filter for Dynamic Ship Positioning

This paper addresses a filtering problem that arises in the design of dynamic positioning systems for ships subjected to the influence of sea waves. Its key contribution is the use of a multiple model adaptive wave filter that relies on measurements of the ship's position and heading only. To this effect, a bank of Kalman filters is designed for a finite number of parameter values, each corresponding to a different peak frequency of the assumed wave spectrum model. Tools from multiple model adaptive estimation (MMAE) theory are exploited to blend the information provided by the different observers, yielding position and velocity estimates of the ship. These estimates are then be used in an appropriately designed feedback control law. Simulations illustrate the efficacy of the MMAE techniques proposed.