星载斜视等距扫描成像

Spaceborne squint isometric scanning imaging

针对传统穿轨扫描成像方式存在的随扫描角度增大分辨率退化严重、大气程辐射差异大影响定量化应用等问题,提出了一种基于斜视等距扫描的成像方法。首先,介绍了该成像方法的原理,根据几何光学理论建立了几何成像模型。然后,基于几何成像模型,给出了大幅宽斜视等距扫描成像过程中扫描方向与垂直扫描方向空间分辨率随扫描角度的关系式,以及幅宽与扫描角度的关系式;进一步给出了该成像体制,通过卫星平台俯仰机动,实现多角度观测时分辨率、幅宽等关系式。最后,结合某预研星载相机进行了仿真分析。结果表明:分辨率退化大幅减小,在扫描角度60°时边缘分辨率退化相比穿轨扫描成像体制的9.3倍降低为2.5倍。为大幅宽成像边缘视场分辨率退化严重的问题提供了一种新的解决途径,对推动超大幅宽、高分辨率、多角度星载遥感的发展具有一定参考意义。

A new spaceborne imaging method based on squint isometric scanning was presented to overcome the problems of resolution degradation and atmospheric radiation difference with scanning angle in traditional crosstrack scanning imaging method. Firstly, the principle of this imaging method was introduced, and the geometric imaging model was established according to the theory of geometric optics. Then, based on the geometric imaging model, the relationship between the scanning direction spatial resolution, vertical scanning direction spatial resolution and width with the scanning angle were given. Furthermore, the expressions of resolution and width for multi-angle observation via satellite pitch were derived. Finally, the simulation results of one pre-research spaceborne imager show that the resolution degradation is greatly reduced. When scanning angle is 60°, the edge view resolution is 2.5 times of central field of view far lower than traditional cross-track scanning imaging method 9.5 times. It provides a new solution for wide width imaging and has a certain reference significance for promoting the development of super wide width, high resolution and multi-angle spaceborne remote sensing.