Subimage fusion for high-resolution ISAR imaging

With the improvement of resolution in the inverse synthetic aperture radar (ISAR) imaging, the effect of the rotational motion of the target is much larger than ever before. In this letter, we propose a novel subimage fusion method to compensate for the large rotational motion in high-resolution ISAR imaging. By dividing the large rotational motion into several small ones, the subimage formation can be realized easily with current ISAR imaging algorithms. At the same time, with the increasing of the number of the subimages, the change of the aspect angle during the coherent processing interval can be very large, and high resolution can be achieved. Moreover, because the whole processing is achieved with Fast Fourier Transforms and vector-multiplication operations, the proposed approach is computationally efficient and has no interpolation operation. Numerical examples are provided to demonstrate the performance of the proposed approach.