一种同步轨道星机双基SAR成像方法

对同步轨道星机双基SAR的成像机理进行了研究，从回波的多普勒历程入手，指出该体制下获取的回波数据在距离多普勒域中存在耦合的现象，经典RD算法对非参考点位置的目标成像在方位向上会产生散焦。通过计算得到了相同多普勒历程方住向位置不同的点在数据域中距离向上的位置变化特征以及不同多普勒历程方位向位置相同的点在数据域中距离向上的位置变化特征，给出了在方位向分割回波数据，在距离向上非线性计算回波多普勒参数的改进成像方法。仿真结果表明，改进的成像算法可以较好地对非参考点位置的点目标完成方位向聚焦。

An Imaging Method of GEO Spaceborne-Airborne Bistatic SAR

The principal of geosynchronous earth orbit(GEO) spaceborne-airborne bistatic SAR imaging is analyzed detailedly in this paper. Based on the Doppler history of echo, the coupling phenomenon in the R-D domain of echo is pointed out. And the non-reference position's imaging target can not be focused in the azimuth direction by classical RD imaging method. So this paper calculates the position change of the points which have the same Doppler course but different azimuth direction in the data's range direction. Likewise, the paper calculates the position change of the points which have the same azimuth direction but different Doppler course in the data's azimuth direction. It gives an improved imaging method which divides up the echo data in the azimuth direction and calculates the echo's Doppler parameters nonlinearly. The simulation result demonstrates that the improved imaging method could obtain better focus in azimuth direction for non-reference position's point target.