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深空激光测距受距离遥远、大气损耗等因素影响，地面站接收到的回波光子数非常稀少，因此研究增加回波光子数的方法对提高系统测距成功概率具有重要的意义。本文在云南天文台1.2m望远镜激光测距系统发射光路中增加摆镜，通过快速高精度控制激光光束传播方向的方法搜索回波光子数较多的指向位置。首先设计了摆镜扫描系统，然后对系统进行仿真分析，模拟系统出射光束偏转角度和能量分布随摆镜偏转角度的变化情况以及利用摆镜进行搜索的效果，最后对测距卫星进行实际观测试验。测量得到系统使用的二维摆镜分辨率为0.2"，经激光发射系统扩束后，可以实现最小0.005"的搜索步长，控制频率在100Hz以上。实际观测结果表明，使用摆镜提高回波率的方法是有效的，并且目标轨道高度越高效果越明显，因此可应用于深空目标激光测距系统。

The number of echo photons in deep space laser ranging is rare because of the long distance, so it is of great significance to study the method of increasing the number of echo photons to improve the success probability of ranging. In this paper, a tip/tilt mirror is added to the transmitting optical path of the laser ranging system of the 1.2 m Telescope of Yunnan Observatory, and the pointing position with a large number of echo photons is searched by quickly and accurately controlling the propagation direction of the laser beam. First, the tip/tilt mirror scanning system is designed, and then the system is simulated and analyzed to simulate the variation of the deflection angle and energy distribution of the outgoing beam with the deflection angle of the tip/tilt mirror and the search effect by using the tip/tilt mirror. Finally, the actual observation experiment is carried out on the ranging satellite. The actual measurement shows that the minimum resolution of the two-dimensional tip/tilt mirror used by the system is 0.2″. After beam expansion by the laser emission system, the minimum search step of 0.005″ can be realized, and the control frequency can reach more than 100 Hz. The actual observation results show that the method of using a tip/tilt mirror to improve the echo rate is effective, and the higher the target orbit height is, the more obvious the effect. Therefore, it can be applied to a deep space target laser ranging system. © 2022 Chinese Society of Astronautics. All rights reserved.