THREE-DIMENSIONAL MEASUREMENT METHOD OF FLATNESS OF LARGE DEPLOYABLE FLAT SAR

Abstract. In order to improve the detection and surveillance capability of space-based SAR, large-size spaceborne SAR antenna is needed, and the scale will reach the order of 100 meters. Antenna deformation induced by space thermal radiation, deployment error and other factors seriously affects the performance of SAR. it is necessary to measure the shape of the antenna in real time and with high precision through a three-dimensional measurement system in orbit. A three-dimensional measurement method combining laser ranging and digital image correlation (DIC) is proposed in this paper. The selection of target and camera in this measurement method is deeply analyzed, and the results show that the corner reflector target and Scheimpflug camera are suitable for this three-dimensional measurement method. For the irregular image of the target, this paper improves the traditional sub-pixel center location algorithm based on DIC algorithm, and the detection accuracy of the new geometric center location algorithm is less than 0.1 pixel. Finally, a three-dimensional integration algorithm integrating one-dimensional information from laser ranging and two-dimensional information from image detection is proposed, and the measurement accuracy of this method is verified by experiments to be less than 0.2 mm.