分析了弹载斜视FMCW鄄SAR的成像几何关系,建立了其点目标回波信号模型和推导了回波信号的二维波数域形 式。大斜视情况下,二次以上的高次距离方位耦合项不能忽略,所以FMCW鄄SAR中常用的改进频率变标算法不再适用。 提出的距离堆栈改进算法在聚焦深度范围内利用相同的斜距值进行距离堆栈操作,其计算效率提高了2D2 fs/(1.57cλ) 倍。与改进的频率变标算法相比,不同斜视角仿真实验的结果验证所提算法的有效性和正确性。

The imaging geometry for missile-borne squint FMCW-SAR is analyzed and the echo signal model from point target and its formula in 2-D number domain are presented in this paper. The two and higher order of the range-azimuth coupling terms can' t be ignored for high squint mode FMCW-SAR, and the improved frequency scaling algorithm can't be used in this condition. The modified range stack algorithm implements the processing of range stack making use of the same slant range within the depth of focus and its computation efficiency will be increased by some times which can be calculated by the formula 2D2 fs/(1.57cλ). Comparing with the improved frequency scaling algorithm, the simulation results for different squint angles test the validity and correctness of the proposed algorithm.