钠导星阵列位置不确定度对多层共轭自适应光学系统性能退化研究

为了进一步揭示宇宙未来是进入大坍塌还是大撕裂状态这一终极科学问题，利用钠导星多层共轭自适应光学（MCAO）系统对星体进行大视场高分辨观测成为了最有力的手段之一。本项目针对激光上行路径湍流倾斜像差导致钠导星偏离理想指向位置，引起整个导星阵列分布的退化，从而降低MCAO系统性能这一问题进行研究。首先，从激光在大气中传输的机理出发，分析上行路径倾斜像差对钠导星位置不确定度的影响，从而建立整个钠导星阵列分布退化的数值模型，并进行全过程仿真验证。第二，根据层析原理，建立钠导星阵列分布与MCAO系统性能的内在模型，并开展室内模拟实验，验证理论正确性。第三，在前期研究基础上，研制钠导星阵列倾斜预校正发射系统，稳定钠导星阵列形状。本项目的实施不仅能够提升我国天文观测水平，具有一定现实意义。同时还将推动我国望远镜发展，抢占天文观测制高点，具有一定先导意义。

In order to further reveal that the ultimate scientific question of whether the future of the universe will enter a state of great collapse or great tearing, the Multi-conjugate adaptive optics(MCAO) system with sodium laser guide star(LGS) becomes one of the most powerful method on observation of star cluster with large field of view and high resolution. This project makes depth research on the performance degradation of the MCAO system that the position of the sodium LGS shift from the ideal pointing position, and the degradation of the entire LGS asterism distribution, which is caused by the tip-tilt aberration on the laser uplink path. First of all, based on the mechanism of laser transmission in the atmosphere, analyzing the effect of the uplink tip-tilt aberration on the uncertainty of the position of the sodium LGS, the numerical model for the degradation of the sodium LGS asterism distribution can be obtained, and a numerical simulation program will be conducted. Secondly, based on the principle of tomography, the inherent model between sodium LGS asterism distribution and system performance can be obtained, and a laboratory experiments will be conducted to verify the correctness of the theory. Thirdly, based on our previous work, a LGS launch system with pre-correction of the tip-tilt aberration on the uplink path will be developed, and the spot position of sodium LGS asterism can be stabilized. The implementation of this project can not only improve the level of astronomical observation in China for the practical significance. At the same time, it will also promote the development of telescopes in China and seize the commanding heights of astronomical observation, which has a certain leading significance.