High-repetition-rate lunar laser ranging (LLR) has great prospects and significance. We have successfully obtained the effective echo signals of all five corner-cube reflectors (CCRs) on the lunar surface by using a 100 Hz repetition rate. This method can effectively improve the detection ability but has some defects: for example, the main wave and echo signals overlap. In this paper, the frequency selection and signal overlap are theoretically analyzed. The results show that the existing target prediction accuracy can meet the requirement of a 100 Hz repetition rate LLR. In the experiment, the use of a high-repetition-rate pulse laser allowed us to obtain detailed CCR information, such as the column number of CCRs, which will prove that the effective echo signals of LLR are reflected by the CCRs. Finally, we propose to use the resolved data to calculate the precision of inner coincidence and believe the accuracy can be within a millimeter.

As the signal reflected by the corner-cube reflector arrays is very weak and easily submerged during the full moon, we analyze the influence of the thermal effect of corner-cube reflector arrays on the intensity of lunar laser ranging echo. Laser ranging measurements during the penumbra lunar eclipse verify suspected thermal deformation in the Lunakhod 2 reflectors. Signal levels vary over two orders of magnitude as the penumbra eclipse progresses. This can be explained by the change in the dihedral angle of the corner-cube reflectors caused by the temperature. The results show that when the dihedral angle errors reach 1″, the energy is reduced by 100 times compared with the ideal corner-cube reflector. In the experiment, our findings suggest that when the corner-cube reflector arrays enter the penumbra of the earth, the effective echo signal level which reaches 0.18 photons/s far exceeds the historical level of the full moon. However, 11 minutes after the penumbra lunar eclipse, the effective echo rate of Lunakhod 2 will drop two orders of magnitude. The mechanism can explain the acute signal deficit observed at full moon.