Near-infrared lunar laser ranging: Research on pointing error of Lunokhod 2 corner reflector based on effective echo signal broadening

Abstract

The effective echo intensity of lunar laser ranging (LLR) has always been a concern, which not only reflects the detection ability of the LLR system but also affects the ranging uncertainty of LLR. The initial pointing of the corner-cube reflector (CCR) has a certain relationship with the echo intensity and ranging uncertainty of LLR. In our previous work, we analyzed the pointing error of the CCR array by studying the change in echo signal intensity. This paper will continue to research the initial pointing error of the CCR array from the perspective of ranging uncertainty. In this paper, based on the ranging system of the TianQin laser ranging station, the ranging uncertainty is obtained by analyzing the data, and finally, the pointing error of the CCR array is researched by summarizing the variation law of the ranging uncertainty. Firstly, the delay model introduced by the pointing error of the corner reflector is established, and the theoretical uncertainty introduced by the pointing error of the corner reflector is calculated. Secondly, the ranging uncertainty is analyzed through the experiment of LLR. Finally, the pointing error of the CCR array is calculated by inversion of ranging uncertainty. Theoretical analysis and experimental measurement results show that there is a pointing error in the L2 (Lunokhod 2) corner reflector, and its pointing error is about 5° ∼ 10°. This study is of great guiding significance for analyzing and studying the ranging uncertainty of LLR and arranging the next generation of LLR reflectors.