地球同步轨道星载SAR观测特性分析

Observation Properties Analysis of Geosynchronous Spaceborne SAR

地球同步轨道星载合成孔径雷达(Geosynchronous Synthetic Aperture Radar,GEOSAR)具有超高的卫星轨道和超长的合成孔径时间,相比于目前的低轨星载SAR,GEOSAR在信号特性与成像信号处理方面变化显著。GEOSAR体制和理论方法的研究都要以GEOSAR自身的特性分析为基础。文中根据GEOSAR的星地几何关系对星下点轨迹、卫星速度与波束扫描速度、合成孔径时间、多普勒特性等观测特性进行了深入分析,然后在此基础上与典型低轨SAR进行比较,得出了相应结论。

Compared with current low-earth orbit spaceborne SAR, GEOSAR is featured in its ultra-high orbit and ultra-long inte- gration time which has great improvement in signal properties and imaging processing. Study of GEOSAR system and theory shall be based on the analysis of its characteristics. A deep analysis of observation properties such as the sub-satellite point under the earth, the satellite velocity and the ground velocity of beam, integration time and Doppler properties which are based on the geo- metrical relationship of the satellite and the ground is made in this paper, and the conclusion is given based on the comparison with the typical low-earth orbit SAR.