从相对距离、大气压力、温度变化三个方面分析了天基光学探测系统离焦产生的原因及离焦变化情况, 提出通过离焦调制传递函数模型分析离焦对系统性能影响的方案, 仿真分析了不同离焦量下系统等效调制传递函数的变化及其对成像质量的影响.结果表明, 随着离焦量的增加, 图像质量逐渐下降, 相对距离变化导致的离焦为正值, 大气压力变化导致的离焦为负值, 温度变化导致的离焦在中心温度左右有正有负, 三者导致的离焦量可部分抵消.该研究为天基光学探测系统的设计、补偿措施的制定以及性能评估提供了数据支持.

The reasons of the generation of defocus were discussed and the defocus change was analysed from the relative distance, atmospheric pressure and temperature change. The modulation transfer function model was proposed to study the image quality influenced by defocus. Then different defocus value leading image blurry was simulated. The simulation results indicate that the positive and negative defocus value induced by the relative distance, atmospheric pressure and temperature change can be counteracted. This paper provides an effective data to spatial camera design, compensating measure establishment and performance evaluation.