ISAR Imaging for Target Above Rough Surface Based on Time-Domain Scattering Echo

The inverse synthetic aperture radar (ISAR) imaging of the target above the rough surface based on the time-domain (TD) electromagnetic scattering algorithms is focused in this letter. It effectively combines the TD ray tracing (TDRT) method for the composite scene and radar imaging model. The scattering echoes for ISAR imaging are solved by TDRT that the TD mutual coupling between the target and rough surface can be considered by the ray bounce strategy. Compared with the frequency-domain ray tracing and multilevel fast multipole method, the TDRT algorithm not only ensures the calculation accuracy but also greatly reduces the calculation cost. Then, we generate the ISAR image of the target above the rough surface according to the echo matrix based on TDRT. In order to improve the imaging quality of the target, the nonlinear mapping theory is presented to suppress the virtual image points and noisy points and it is beneficial to the future research of target recognition in the composite scene.