中文摘要：

俯冲加速阶段导弹运动状态复杂，成像范围需求大，回波处理困难的特点使得传统的成像算法难以运用．针对这一问题，本文首先建立了精确的斜距几何和回波模型，并在分析二维频谱的基础上，提出了一种基于变量解耦下的非线性变标算法，有效的补偿了随场景纵向和横向的多普勒调频率，改善了方位聚焦质量和位置的正确性，提高成像质量的同时简化了后期图像几何校正操作．多个散射点的仿真数据和结果表明了算法的有效性．

英文摘要：

The ordinary SAR imaging algorithms are inapplicable to missile-bo-rne SAR due to the high speed dive and high- squint of missile. Aiming at this problem, this paper firstly sets up the model of echo and analyses of two-dimensional spectrum. By using azimuth nonlinear chirp scaling （NLCS） based on variable decoupling, an imaging algorithm for missile-borne SAR is proposed.It can effectively compensate the scene with longitudinal and transverse Doppler shift and improve the focusing quality while it can also simplify the geometric image correction operation. Simulation results are provided to confirm the effectiveness of the proposed algorithm.