基于图像旋转相关的空间目标ISAR等效旋转中心估计算法

为了消除逆合成孔径雷达(ISAR)越分辨单元徙动(MTRC)引起的图像散焦，需要估计目标的等效旋转中心。该文以空间目标为研究对象，提出了一种基于图像旋转相关的ISAR旋转中心估计算法。首先，分析了ISAR的瞬时成像机理；其次，将采用相同运动补偿后的回波数据分段成像，得到不同视角的2幅图像；然后，基于定标后的图像像素旋转和图像相关，估计等效旋转中心。当假定的等效旋转中心与真实的旋转中心一致时，2幅图像相关性最大，据此得到旋转中心位置。仿真实验表明，该算法能够有效利用图像整体信息，估计出高精度的目标等效旋转中心，利于提高成像质量。

Rotation Center Estimation Algorithm for ISAR Image of the Space Target Based on Image Rotation and Correlation

The equivalent rotation center should be estimated accurately in the Inverse Synthetic Aperture Radar (ISAR) for the issue of image defocusing induced by the Migration Through Resolution Cells (MTRC). In this paper, an equivalent rotation center estimation algorithm based on image rotation and correlation is proposed for the space target. First, the instantaneous imaging mechanism of ISAR is analyzed. Second, two images with different observation angles are obtained by using the echo data with the same motion compensation algorithm. Finally, the equivalent rotation center is estimated based on the scaled image pixel rotation and image correlation. Consequently, the estimated position of the rotation center is obtained, when the assumed rotation center is in accordance with the real one and the maximum correlation coefficient of two images is achieved. The results demonstrate the effectiveness and robustness of the proposed algorithm.