DESCENT TRAJECTORY RECOVERY OF CHANG’E-4 LANDER BASED ON DESCENT IMAGES

Abstract. Chang’e-4 lander, carrying Yutu-2 rover, was successfully landed on the far side of lunar surface in Von Kármán crater inside the South Pole-Aitken basin on January 3rd, 2019. The descent images, captured by the descent camera mounted on the lander, captured the sequential descent images and recorded the scene changes during the entry, descent and landing (EDL) process. This paper proposed a bundle adjustment based geometric processing method for descent and landing trajectory recovery using descent images. A frame camera based self-calibration model was introduced for high precision estimation of interior and exterior parameters of descent images simultaneously in a least squares manners. Evenly distributed GCPs were selected from the landing area in a digital orthophoto map generated from LROC NAC images and SLDEM2015. The experimental results demonstrated the effectiveness of the proposed method in Chang’e-4 descent trajectory recovery.