改进的大斜视角SAR阶梯变换算法

An Improved Step-Transform Algorithm for High Squint SAR Processing

针对大斜视角下合成孔径雷达信号时域距离校正后的特点,提出了改进的阶梯变换算法,在各个子孔径分别采用不同调频斜率的参考信号进行去斜处理,解决了信号多普勒调频斜率随方位时间变化的问题;通过频域插值准确挑选粗分辨傅里叶输出数据,克服了原有阶梯变换算法对参数匹配的严格限制。实验结果表明:该算法在大斜视情况下是有效的。

An improved step-transform algrithm is proposed for high squint mode synthetic aperture radar（SAR）. It uses different chirp rates to deramp the signal in different subapertures to alleviate the varying of chirp rate with the azimuth time, and to accurately select data from the coarse-resolution FFT output by approximate interpolation in frequency-domain and to remove the tight constrains for the parameter in time-varying step-transform. The performance of the algorithm is efficient in high squint mode.