大斜视角SAR成像的改进频率变标算法

High squint SAR data processing using a modified frequency scaling algoritfam

首先给出了一种改进的频率变标算法。该算法适用于处理距离解线调后的聚束式SAR数据。对大斜視角数据,由于二次距离压缩误差的影响,偏离参考距离的散射点未能完全聚焦,且离参考距离越远聚焦性能越差。将非线性变标的方法加入频率变标算法对数据进行二次距离压缩,有效地减小了距离压缩误差。最后通过仿真实验表明,对给定的SAR参数,在斜视角为定值时,也能得到较好的成像结果。

A modified frequency scaling algorithm to process the high squint spotlight SAR data is presented. The original frequency scaling algorithm corrects the range migration successfully by a frequency scaling operation. But it compensates the range-dependent secondary range compression (SRC) using the SRC at the reference range. So the targets beyond the focus depth, which becomes shorter and shorter as the squint angle goes high, will be defocused. A nonlinear scaling operation is adopted to cope with the range-dependent SRC after the frequency scaling operation. Simulation results show that, in the given circumstances, the well-focused images can also be acquired when the squint angle is up to 70 degrees.