天基平台海云背景下飞机全链路成像特征建模及分析

Modeling and analysis of aircraft full-chain imaging characteristics in the sea surface and clouds from a space-based platform

空中目标具有高速机动、战略突防和远程精确打击等特点,针对这类目标构建广域、高效、精准探测、连续监视技术已成为空中目标探测体系面临的新挑战。基于空中目标的天基光学探测需求,建立了复杂环境要素综合作用飞机尾焰的光学辐射特征模型,形成飞机尾焰-海面/云层背景-环境大气-光学系统-成像探测器等要素耦合的全数字化链路光谱辐射成像特征精确预测模型。基于实测数据推演了飞机尾焰红外多光谱本征辐射。同时,利用FY-2G遥感数据,反演了中国南海某海域海面温度及云顶温度分布,建立了海云背景光谱辐射模型。在此基础上综合考虑了背景辐射、大气路径辐射和大气衰减对飞机尾焰光谱辐射的影响,建立了在光学系统入瞳前目标上行光谱辐射特性模型,结合光学成像系统的衍射效应,探讨了不同谱段、云类型下地球同步轨道红外成像系统对目标的可探测性。研究表明:大气屏蔽波段对目标的探测效能优于宽波段;针对不同的背景选择合理的探测波段有利于目标的高效探测。

The air target has the following characteristics: high-speed maneuver, strategic deep penetration and long-range precision strike. Building wide-area, high-efficiency, accurate detection and continuous monitoring for air targets has become a new challenge for air target detection. In view of the optical detection requirements of air targets, a radiation characteristic model of aircraft plume was established under the combined effect of complex environmental factors. An accurate prediction model of the full chain including aircraft plume-sea/cloud background-environmental atmosphere-optical system-imaging detector was formed. The infrared multi-spectral self-radiation of the aircraft plume was derived based on the measured data. At the same time, the FY-2 G remote sensing data was used to invert the sea surface temperature and cloud top temperature distribution in a certain sea area of the South China Sea, and the background radiation model of sea/cloud background was established. On this basis, the effects of background radiation, atmospheric path radiation and atmospheric attenuation on the spectral radiation of the aircraft plume were considered. A model for the upstream spectral radiation of the target at the entrance of the optical system was established. Combined with the diffraction effect of optical imaging system, the detectability of the infrared imaging system in the geostationary orbit under different spectral segments and cloud types was discussed. Research shows that detection efficiency is better in the atmospheric shielding band than in the wide band, and reasonable detection band selection in different backgrounds is conducive to efficient detection of targets.