Least squares identification of linear sway-yaw manoeuvring coefficients and drag-area parameters of ships

The purpose of this paper is to present a simple least squares technique for identifying a ship’s linear sway-yaw manoeuvring coefficients and drag-area parameters in current and wind, using measured data. These coefficients are required inputs to a standard three-degree-of-freedom manoeuvring model. The identification method employs the BFGS algorithm which avoids direct computation of the Hessian of the residual function. The results of test simulation problems are discussed and an identification example with measured data is presented. The applicability and limitations of the algorithm are discussed.