自主光学导航是小行星探测任务的一项关键技术，基于光学图像的地形相对导航方法在以往开展的小行星探测任务中得到了成功的应用。光学导航利用小行星表面的地形和反照率等特征精确建立了参考基准和导航陆标，根据实时观测图像的匹配结果给出了下降过程中精确的相对位置、姿态和速度。文中总结了小行星探测器下降着陆的光学导航技术发展现状，概述了其关键技术和发展趋势，为国内小行星探测任务提供了参考。

Autonomous optical navigation is a key technology for asteroid exploration missions. Terrain relative navigation methods based on optical images have been successfully applied in previous asteroid exploration missions. Optical navigation uses features such as the asteroid''s surface topography and albedo to accurately establish reference datums and navigation landmarks, and give precise relative positions, attitudes, and velocities during descent based on the matching results of real-time observation images. The development of optical navigation technology for asteroid probe descent and landing was reviewed, and its key technologies and development trends were summarized, which provided a reference for China''s asteroid exploration mission.