斜视SAR成像的逆变标傅立叶变换算法

Inverse Scaled Fourier Transformation Algorithm for Squint Mode SAR Imaging

逆变标傅立叶变换(ISFT)算法在二维频域内利用ISFT的逆变标特性对SAR回波的距离徙动进行校正,提高了距离徙动校正的精度和计算效率,成为一种重要的频域类成像算法。本文对该算法的处理过程进行了研究,重新定义了用于距离压缩的调频率表达式,使其能够包容二次距离压缩,又进一步修正了ISFT运算中距离频率的一次项系数,使改进的ISFT算法能够适应斜视SAR数据处理的要求。仿真实验验证了这种改进的ISFT算法在处理斜视SAR数据时的有效性。

Inverse scaled Fourier transformation（ISFT） algorithm uses the inverse scaling property of ISFT to perform the range cell migration correction（RCMC） of SAR echoes in two-dimensional frequency domain in order to improve the corrected precision of RCMC and the computational efficiency,so it has become an important frequency domain algorithm.The paper studied the processing procedure of the algorithm,and redefined the expression of the chirp rate used to the range compression,which made the algorithm to accommodate secondary range compression（SRC）.Further,one-order term coefficient of the range frequency in ISFT algorithm was modified.The modified ISFT algorithm is suited for the demands on data processing of squint mode SAR.The simulation tests validated the modified ISFT algorithm to process the squint mode SAR data.