Fig. 1. Flowchart for calculating terrain illumination around lunar laser retroreflector

Fig. 2. Schematic diagram for terrain elevation angle

Fig. 3. Schematic diagram for calculating maximum terrain elevation angle at given azimuth angle

Fig. 4. Schematic diagram illustrating relationship between path points and target location

Fig. 5. Schematic diagram of the camera imaging model based on ground-based laser ranging system

Fig. 6. Schematic diagram of the lunar laser ranging model

Fig. 7. Schematic diagram of camera imaging principle

Fig. 8. Schematic diagram of the optical system for the TianQin laser ranging station

Fig. 9. Optical path diagram of primary optical system for 1.2 m alt-azimuth telescope

Fig. 10. Binning function of camera

Fig. 11. Comparison between simulation and actual images of five lunar laser retroreflectors. (a) Simulation image of Apollo 11; (b) simulation image of Apollo 14; (c) simulation image of Apollo 15; (d) simulation image of Lunokhod 1; (e) simulation image of Lunokhod 2; (f) real photo taken by Apollo 11; (g) real photo taken by Apollo 14; (h) real photo taken by Apollo 15; (i) real photo taken by Lunokhod 1; (j) real photo taken by Lunokhod 2

Fig. 12. Comparison between simulation and actual images of Apollo 15 and Lunokhod 2 lunar laser retroreflectors. (a) Simulation image of Apollo 15; (b) simulation image of Lunokhod 2; (c) real photo taken by Apollo 15; (d) real photo taken by Lunokhod 2