Study Of The Inertial Matching Techniques To Estimate The Ship's Deformation

In order to establish unified attitude datum of entire ship, it's necessary to estimate the deformation of ship's deck. The paper studies the deformation rule , the influence of the dynamic deformation on attitude, building the model of the attitude error of the strapdown inertial navigation, and estimating the deformation by the method of inertial measurement which mainly researches on the angular rate matching method and the velocity plus attitude matching method.The angular rate matching algorithm uses two methods to estimate deforming angles. The first method is realized by the Kalman Filter which take the static and dynamic deforming angles as small angles, deduces their linear state equation and directly brings the dynamic deforming angles into the state variable, then we get the dynamic deforming angles at the same time of getting static ones. The second method is iterative method. The angular rate of the main inertial system(MINS) is caused by the rotation of earth and the movement of the carrier, besides these two items, single inertial system(SINS) also has the deforming angle rate of itself, then the transformation relations between the dynamic deforming angles and rate can be iterated. After several steps of iterations, the dynamic deforming angles can track the output of the model.The velocity plus attitude matching algorithm is a rapid and efficient method of transfer alignment. It uses two inertial systems which are different in the precision. The higher is MINS, and the lower is SINS. The method takes their output velocity difference and attitude difference as the observation variable and takes the velocity , attitude, static deforming angles and dynamic deforming angles as the state variable. Then we can estimate the static deforming angles and dynamic deforming angles.