Three-Dimensional ISAR Imaging under Low SNR

Obtaining the scatterer slant range and scatterer trajectory association are two crucial steps of 3-D target imaging from the inverse synthetic aperture radar (ISAR) image sequence or high resolution range profiles (HRRP) series. However, scatterers are drowned out by noise at low SNR so that the scatterer slant range cannot be obtained. In addition, the minimum Euclidean distance criterion is a common trajectory method, which will lead to wrong association results when the scatterer trajectory has crossings. To tackle above problems, a novel ISAR 3-D imaging method based on Generalized Radon-Fourier Transform (GRFT) is proposed. In this method, the slant range history of the scatterer is reconstructed based on GRFT without trajectory association. In addition, GRFT is a parameter estimation technique with robustness at low SNR. The 3-D image of the target is obtained using the factorization method. Simulation results prove the effectiveness of the proposed method.