A 3D Instantaneous Imaging Method for Maneuvering Targets

Three-dimensional (3D) imaging accurately depicts target posture and structure, providing rich feature information for space target identification. Well-focused Inverse synthetic aperture radar (ISAR) images serve as the foundation for 3D interferometric ISAR (InISAR) imaging. For maneuvering targets, it has been demonstrated that the Doppler frequency shift of their echoes varies over time. Additionally, keystone transformation cannot fully correct its Migration through resolution cells (MTRC) along the range dimension. Consequently, the range-Doppler algorithm fails to produce a clear two-dimensional (2D) image of maneuvering target. To enable 3D imaging based on defocused 2D images, a new method for 3D instantaneous imaging is proposed. First, a set of point clusters is obtained from defocused ISAR images. Then, the Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm is utilized for classification and denoising of the point clusters. The matching of point clusters between images is achieved through a scatterer association algorithm. Finally, the scatterers are inversely processed to obtain their high-resolution range profiles (HRRP), and the instantaneous 3D image of the target is acquired by 3D imaging method based on phase-derived technology.