The prediction of ship motion via updating MGM(1,n) model

Effected by the influencing factors in the ocean, the ship motion becomes a complex system consists of six degrees of freedom. The pitch motion and heave motion in the system play the key role in the safe landing of battle plane. So establishing a system model to control and predict the ship motion in real time has a significant practical meaning. The MGM (1, n) which depicts the influence degree from n elements to one certain element in system via a group of differential equations is usually being applied to predict. Based on the MGM (1, n) model, the updating MGM (1, n) model is proposed in this paper which is applied to predict the pitch motion, heave motion and wave in the grey system. The data got from the pool experiment are applied to Range Transform and the data predicted from the MGM (1, n) model are reused to update the original data for continuing to predict the ship motion. In the numerical computations, the time of predicted ship motion can last 13 seconds within the relative error of 20%. It is about a period of pitch motion. In the different sea conditions, the predictions of updating MGM (1, n) are analyzed, and the different application situations of model are given.