3-D InISAR imaging for targets with complex motion based on linear canonical transform

Abstract

The two-dimensional inverse synthetic aperture radar (2-D ISAR) image is a 2-D projection of the three-dimensional (3-D) shape of the target, and it is difficult to meet the demand of recognition and classification, especially of targets with complex motion. Recently, interferometric ISAR (InISAR) has been receiving increasing attention since it can reconstruct the 3-D shape of the target with high resolution. This paper proposes a novel 3-D InISAR imaging algorithm based on linear canonical transform (LCT) for targets with complex motion. In this method, the initial echo signal model is generated after analyzing the complex motion of the target. After motion compensation and image coregistration, the azimuth echo is modeled as linear frequency modulation (LFM) signal. Given the time-frequency characteristics of LFM signal, then a new 2-D ISAR imaging algorithm based on LCT is developed to obtain well-focused and multi-channel 2-D ISAR images as well as preserve the phase information of images. Finally, employing the interferometric technique, a novel 3-D InISAR imaging method is proposed and the high-resolution 3-D shape of the target can be reconstructed. In addition, the time-frequency concentration, moderate computation cost and effect of baseline are discussed, and different simulation experiments and results verify the superior performance of the proposed method.