Abstract: The lunar penetrating radar (LPR) data play an essential role in studying the lunar soil layer structure of the Von Karman crater on the back of the moon and analyzing the lunar chronological activities. Because the geological conditions of the Chang’e-4 landing area are complex, using advanced radar data processing technology and methods to obtain high-precision LPR imaging results is an important basis for lunar-related scientific research. Based on previous studies, the focusing algorithm based on the synthetic aperture focusing technique (SAFT) migration imaging is performed on the Chang’e-4 LPR 500 MHz data in this paper. Compared with the traditional f-k migration results, the method improved the imaging resolution. The proposed SAFT method can more finely reflect the vertically layered structure and horizontal interface fluctuation of the lunar soil layer. The LPR data interpretation section indicates that the lunar soil layer contains a shallow topsoil layer of about 12 m from Finsen crater within a depth of 40 m, about 17 m from the sputter layer of the crater around Von Karman and the lowest basaltic rock layer. 

Key words: Chang’e-4, lunar penetrating radar, synthetic aperture focusing technique, migration imaging, regolith structure