An attitude determination method for satellite by the use of image data of a phase of a heavenly body

This paper shows a rapid attitude determination method for satellite using the shape of the heavenly body which goes through phases. At first the image of heavenly body is binarized and the image centroid is derived from the image. The translational displacements are obtained by comparing the image centroid of the reference image with that of the obtained image, i.e. attitude angles for two axes are determined. Next, the images are represented in polar coordinates and the feature points are represented by two peaks. The rotational displacement is obtained from these peak points, i.e. attitude angle of remaining one axis is determined. This method enables the attitude to be obtained more rapidly than the conventional image processing, e.g. image correlation method. The parameter dependences of the accuracy of the attitude determination by the proposed method are studied by numerical analysis. In addition, the effectiveness of the method is evaluated by the simulating the operation of the satellite with the proposed attitude determination system.