ECHO MODELING FOR ASTEROIDS WITH ROUGH SURFACE IN GOUND-BASED SAR IMAGING

With the development of radar imaging technology, asteroid imaging has become one of the focal points in astronomical radar research. However, in simulation and verification experiments for asteroids observation, the traditional point target approximation method is often inadequate in capturing geometric features and surface topography of asteroid. To address this issue, this paper proposes an improved method for generating asteroid echo specifically tailored for asteroid imaging tasks. Firstly, the relative motion between the radar and the asteroid is calculated to determine the slant range phase. Simultaneously, an amplitude factor that varies with the observation angle is introduced, correcting the isotropic scattering of traditional point target. Subsequently, considering the rough characteristic of asteroid surfaces, an echo generation process is presented based on the Monte Carlo method. Finally, computer simulation experiments are conducted to complete the echo generation and radar imaging of asteroid and its typical surface topography features. The experiments validate the correctness and effectiveness of the proposed method.