近空间高速流场环境小目标探测分析与试验

随着空间安全与应用探索的不断深入，近空间飞行器目标探测效能成为研究的核心问题。光学成像探测能够直观反映目标的形态、光谱与运动特性等多维度信息，因此成为空间探测感知的重要手段。在近空间大气密度、气压、对流等条件作用下，导致高速飞行器光学探测设备成像质量与探测性能衰减。采用以成像系统、大气传输系统和目标背景系统为要素的目标探测分析模型，根据气动光学效应理论，建立高速流场气动光学效应评价方程，对深空、近地等典型应用场景进行成像探测分析。设计了高速流场环境下目标探测地面验证试验，仿真测试结果表明，针对空间高速飞行目标，采用900~1 700 nm谱段短波红外探测器配合厚度10 mm以上石英窗口，对尾焰目标辐射具有良好观测效果；通过降低探测设备曝光时间、优化曝光控制策略及选用光学带通滤光片等方式，能够有效抑制背景杂光与气动光学效应影响。

Analysis and experiment of small target detection in high speed flow field of near space

With the deepening of space security and application exploration, the target-detectability of space vehicle in near space has become a core issue of research. For some multi-dimensional information of target, such as shape, spectrum and motion characteristics, can be directly captured by optical imaging detection device, optical detection has become an important means of space imaging and target detection. Under the conditions of atmospheric density, pressure and atmospheric convection in near space, imaging quality and detection range of optical detection device installed in high-speed aircraft could be affected seriously. By using target detection model with three analysis elements (imaging system, atmospheric transmission system and target-background system) and the theory of aero-optical effect, evaluation equation of aero-optical effect for high speed flow field has been established, to analyze imaging performance of typical scenes such as earth and space background. A ground verification test of target detection in high speed flow field has also been designed. The experimental results show that it’s an effective way for detecting plume flow of high-speed space targets by using short wave infrared detector (SWIR: 900-1 700 nm) with quartz window (with thickness of more than 10 mm). Meanwhile, by reducing exposure time of camera, optimizing exposure control strategy and selecting optical filter, stray light in background and aero-optical effect can be effectively suppressed.