Surface Clutter Separation for Asteroid Radar Imaging in the Tianwen-2 Mission

The Tianwen-2 probe carries an asteroid core-scanning radar (ACSR) to study the internal structures of near-Earth asteroid 2016 HO 3 and main-belt comet 311P. Radar signals are often contaminated by surface clutter, which can overlap with weaker subsurface echoes due to propagation attenuation. This paper proposes a surface-clutter separation method based on cross-correlation and moment-matching algorithms. It realizes effective separation by performing joint calibration of the position and amplitude of surface clutter. The simulation results demonstrate that this method can effectively separate surface clutter across various detection scenarios. Ground-test data further validate the method’s capability to separate dominant surface clutter in in situ detections. These results indicate that the approach is effective for investigating the internal structures of asteroids and comets in the Tianwen-2 mission.