Simulation of Lunar Comprehensive Substructure With Fracture and Imaging of Later LPR Data From Chang'e-4 Mission.

As one of the most important geophysical methods for detecting the lunar underground structure of the Moon, the lunar penetrating radar (LPR) is applied to the Chang'e-4 (CE-4) mission to explore the Von Karman crater on the far side of the Moon. With the Yutu-2 rover continuing to move toward the Zhinyu crater at the west, radar will likely detect the fractures created by the impact that formed the Zhinyu crater. Therefore, the establishment of a comprehensive lunar subsurface structure model with fracture, random media, and fractal terrain is crucial for the LPR data processing and the understanding of the lunar geological impact process. In addition, the method that can image the radar data with fractures well has great significance to the interpretation of the LPR data. In this article, we establish a comprehensive lunar subsurface structure model first, and the considering factors, including fractures, random media, fractal terrain, and the radar response, are calculated through forward modeling. Second, according to the high resolution and the sensitive to inhomogeneities of LPR data, we design a set of processing flow, including plane-wave destruction (PWD), velocity analysis based on the focusing analysis method, and migration imaging based on the velocity continuation. Finally, the results, including simulation data and Antarctic fracture data, are used to verify the effectiveness of imaging method.