High Resolution 3D InISAR Imaging of Space Targets Based on PFA Algorithm with Single Baseline

High resolution Three-Dimensional (3D) image of space targets can be achieved under large relative rotational angle, providing precondition for high-precision recognition of space targets. Under large relative rotational angle, the large Migration Through Resolution Cells (MTRC) and the highly Doppler Frequency Modulation (DFM) arise in the Two-Dimensional (2D) Inverse Synthetic Aperture Radar (ISAR) imagery, which results that the existing 3D Interferometric ISAR (InISAR) imaging methods suffer from poor imaging quality. To address this issue, we propose a high resolution InISAR imaging method under large relative rotational angle with single baseline, which is excellent in providing high resolution 3D image of space targets and simplifying system structure compared with the traditional InISAR image methods. Firstly, Polar Format Algorithm (PFA) is performed to eliminate the impact of MTRC, and the second-order Local Polynomial Fourier Transform (LPFT) is applied to reduce the azimuth defocuing. Then, the cross-range scaling technique is adopted to obtain the accurate vertical and horizontal coordinates of the scatterers. Finally, the height coordinates of the targets can be obtained by interferometric processing. Simulational experiments demonstrate that the proposed method can achieve high resolution 3D imaging for space targets under large relative rotational angle with low hardware complexity.