摘要
为了提高对全球变化的大尺度观测能力,月基对地观测的概念应运而生。由于月基单站合成孔径雷达(Synthetic Aperture Radar,SAR)的双程传播会造成回波信噪比衰减,为此针对月地双基SAR工作模式展开研究。考虑到月、地、星复杂的相对运动为成像带来困难,根据月、地、星的几何关系建立平面直角回波模型。同时考虑到月球和卫星运行轨迹的弯曲性,分析模型误差,推导了精确的回波二维频谱表达式。在此基础上提出了一种基于快速后向投影的SAR成像算法,补偿了方位空变的模型误差,利用频域子孔径成像和频谱融合实现成像算法的快速化。通过分析可知月地双基SAR的理论回波信噪比与地月距离的平方成反比,与月基单站SAR相比有显著提升,最后通过X波段SAR仿真数据验证了文章算法处理月地双基SAR成像问题的效性。
The concept of lunar-based earth observation concept has been proposed in order to improve the large scale observation ability towards global changes. Because the signal to noiseratio of lunar-based monostatic synthetic aperture radar （SAR） decreases seriously due to the two-way propagation, a novel lunar-earth bistatic SAR operating mode was studied. Considering the complex relative movement among lunar, earth and satellite brings difficulty to SAR imaging, a rectangular plane echo model was built according to the geometrical relationship of lunar^earth and satellite. Due to the curves of lunar and satellite orbits, the modeling error was analyzed,and aprecise two-dimensional frequency domain expression of echo was also deduced. Then a fast back projection based SAR imaging algorithm was designed to compensate the azimuth variant modeling error. The calculation speed was increased by frequency domain sub-aperture imaging and spectrum combination. The signal noise ratio of lunar-earth bistatic SAR is inversely proportional to the distance between earth and lunar through analysis,simulated X-band SAR data sets are used to validate the effectiveness of the proposal to deal with lunar-earth bistatic SAR imaging.
出处
《中国空间科学技术》
EI
CSCD
北大核心
2017年第6期32-39,共8页
Chinese Space Science and Technology
基金
国家自然科学基金(61771372
61771367)
作者简介
王冠勇（989-）男,博士研究生,gywang.sar@gniail.com,研究方向为合成孔径雷达成像技术;通讯作者：张晶（1984-）,男,副教授,leizhang@xidian.edu.cn,研究方向为合成雷达成像技术
