Study On The Ship Maneuverability Based On Kalman Filter

Ship maneuverability is one of the important performances of navigation. International Maritime Organization(IMO) proposed the criteria for ship manoeuvrability with the guides of evaluation and requirements.In order to analysis ship maneuverability,the ship motion model should be selected.The linear ship motion model is suitable for low frequency of ship motion.The key element of model is hydrodynamic derivatives. And the solutions available to determine the element, i.e., the methods of database or empirical formula,captive model tests,theoretical and numerical calculation,and system identification.The system identification avoids the disadvantages of interpolation error, scale effect and complication of the numerical calculation. As the renovation of measurement system, system identification becomes more capable in the research of ship motion model.The training motor vessel carries the systems of ship state measurement with high accuracy and good performance, and conducted a series of manoeuvre tests with stimulating characteristics of ship maneuverability sufficiently.Therefor the advantage of system identification based on ship test is obvious.As one method of system identification,Kalman Filter(KF) possesses the characteristic of minimum variance unbiased estimation and the ability of online identification without the previous data.To obtain the valid data for identification, the analysis and processing should be implemented. With consideration of the characteristics of ship model and data, the parameters can be obtained from identification with KF.In order to confirm the validity and accuracy, the comparison and simulation is carried out.The result shows that KF identification method is feasible in the research of ship motion model identification.This paper studied ship’s maneuverability based on KF, the main work can be summarized as follows:(1) The one-step recursive theory from Target Tracking Algorithm of Radar addresses abnormal data and improves the validity of the data. Additionally,the spline smooths the data.(2) Analysis the accuracy of speed from log with Dead Reckoning algorithm, and obtain the valid data of current from Differential Global Positionning System(DGPS).Then the simulation shows the correctness of current data.(3) Acomplish the identification of parameters applied in the state space linear ship motion model motion and ship maneuverability indexs.The comparison between simulation and ship test is carried out. The result shows that KF identification method is feasible in the research of ship maneuverability.