We need to know exactly the location and the shape of the ship and control its motion because of these effects. In this paper we propose the method with which we know the current status of the ship without dynamic equations of the ship. We expect the movement of the ship using the GPS absolute axis. But, the original error by the GPS and the movement of the ship cause the result of the GPS of not being accurate. This paper reduces the error of the location and the shape of the ship and gives the exact values of the ship movements even if the GPS implies some error itself.