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[Objectives]In recent years, ships are becoming larger, faster and more intelligent, so the ship dynamic positioning technology is particularly important. In order to establish a kinematic mathematical model in the dynamic positioning system,we need to determine the values of the parameters in the model.[Methods]Firstly,a dredger is used as the research object to establish the mathematical model of the ship movement,and the surge motion model and the sway and yaw motion model are extracted. The unknown parameters in the model are identified based on the system identification theory and the Feedback Particle Filter(FPF)algorithm,including the thrust coefficients of two main thrusters and one side thruster. Then,the parameters to be identified are obtained by the simulation experiment.[Results] Finally,by comparing with the Extended Kalman Filter(EKF)algorithm,it is shown that the FPF algorithm is better at identifying the parameters and the reliability of FPF algorithm is verified.[Conclusions]This method has good application prospect in ship dynamic positioning system.

Aiming at the problem in which a vessel's dynamic positioning system can control it at an expected position,a novel linear active disturbance rejection controller is designed to solve the problem of poor dynamic performance due to the omission of a tracking differentiator. Based on the advantages of linear and nonlinear tracking differentiators,an improved tracking differentiator is designed which can track the differential signal and degrade the effects of noise; it constitutes a novel Linear Active Disturbance Rejection Controller(LADRC). The simulation results show that the novel LADRC based on the improved tracking differentiator has strong robustness,high control accuracy and good dynamic performance compared with the traditional LADRC.