中文摘要：

该文提出一种基于递推公式的星载合成孔径雷达（SAR）高效正向定位算法。该算法利用3组递推公式计算待定位像素与参考像素之间的3轴位置增量，输入参数为两者之间的高程差、斜距差和方位时间差，然后将位置增量与参考点的位置相加即可求得待定位点的定位位置。3组递推公式通过分别以斜距、方位时间和高程为变量，并对定位方程组求导获取。该算法避免了3维格网建立、系数拟合和插值操作，仿真和实测数据定位结果验证了该文方法的精确性和有效性。

英文摘要：

A novel efficient geolocation method for spaceborne Synthetic Aperture Radar （SAR） is proposed based on recursion formulae in this paper. In this method, three groups of recursion formulae are utilized to compute the three-axis position increments between the position-unknown pixel and the adjacent position-determined pixel, i.e. the reference pixel, with the input increments of the height, slant range and azimuth time between the two pixels. Subsequently, these increments are added to the position of the reference pixel to obtain the position of the position-unknown pixel. Regarding respectively the height, slant range and azimuth time as the variables, these recursion formulae are acquired by differentiating the geolocation equations. Consequently, the construction of three-dimensional grid, coefficients fitting and interpolation are avoided in this method. The geolocation results of simulated and real data validate the accuracy and effectiveness of this method.