实现同步轨道(GEO)高分辨力对地观测的技术途径(上)

Realization of high-resolution visible earth observation on geostationary earth orbit

在地球静止同步轨道(GEO)上实现高分辨力对地观测,具有一系列独特优点,远为其它轨道所不及。然而,对于36000 km的远程高分辨力可见波段观测,要求望远镜必须具备20 m以上口径的主镜。传统的空间相机,如果要有如此大的口径,其总质量将超过1000 t,无法发射到GEO上。无支撑薄膜望远镜和大口径衍射望远镜,可以大幅度降低主镜质量面密度,从而降低整个相机系统的总质量,可算是一种极好的技术途径。分步发射与在轨装配,则提供了可供此类观测系统实施从地面转运到GEO的技术手段。基于变换成像原理的傅里叶望远镜,将高分辨力的取得,由增大接收口径转变为加大发射间隔,用大面积回波能量探测加上傅里叶分量重构,取代常见的目标图像直接探测,突破了远程高分辨力观测的致命瓶颈。近完美透镜为突破衍射极限提供了可能性,从而为超分辨力观测开拓出一片科学的新天地。负折射率材料(左手型材料)可制成完美透镜,而光子晶体是负折射率材料的热门选择之一,基于表面等离子激元(SPP)的光子器件则是其另一种选择。

Abstract： High-resolution visible earth observation on the Geostationary Earth Orbit （GEO） has a series of unique advantages over that in the other orbits. However, long range and high-resolution visible observation requests a large primary mirror more than 20 m in the diameter. The traditional Space Telescope （ST） with and lower down the total mass of the ST, which offers an excellent technologic approach to earth observation. Moreover, both the launching by module and the assembly in an orbit provide the technological means to tranport these kinds of observation systems from ground to GEO. Fourier telescope based on the theory of transform imaging changes the acquirement for high-resolution from increasing the receiving diameter into increasing the illumination interval, and from detecting and reconstructing Fourier components. It breaks the object image directly into receiving the echo energy through the fatal bottleneck of the long range arid high- resolution observation. Recently, a near perfect lens has been developed to provide the possibility for break- through of diffraction limit, so that a new science field will be set up for super-resolution observation. The perfect lens makes of negative refractive index materials （left-handed materials） and the negative refractive index materials come from both of the photonic crystals and the photonic devices based on Surface Plasmon Polariton （SPP）.