并行机载双站斜视SAR ELBF-CS成像算法

ELBF-CS imaging algorithm for parallel airborne bistatic squint SAR

论文建立了并行机载斜视双站SAR的结构模型和信号模型,用收发载机多普勒贡献比为加权系数推导了点目标回波的扩展Loffeld频谱公式(ELBF)。在二维频域内补偿双站扭曲项,然后对剩余相位项做Taylor展开,利用Chirp Scaling(CS)方法,推导了并行机载双站斜视SAR的ELBF-CS成像算法。双站结构参数及双站扭曲项的距离向空变性用回波数据的距离向分块处理,推导了数据分块条件,由此可以实现宽场景成像。算法基于更精确的ELBF,并用CS方法校正点目标距离徙动,处理流程更简单,成像效率更高,仿真验证了本文算法处理并行机载双站斜视SAR数据的有效性。

Based on the geometrical model and signal model of parallel airborne bistatic squint SAR（Bi-SAR）,extended Loffeld bistatic formula（ELBF） of point target echo is derived by using the weighting factors that is defined by the Doppler contribution ratios of the transmitter and receiver.Bistatic deformation is compensated in the two-dimensional（2-D） frequency domain,residual phase items in spectrum expressions are expanded using Taylor series expansion,and the ELBF-CS imaging algorithm of parallel airborne bistatic squint SAR is deduced combining with the CS theory.The variance of bistatic parameters and bistatic deformation in range can be compensated by data blocking in range,so the algorithm can be easily expanded to wide scene focusing.With more accurate 2-D frequency spectrum formula and good range cell migration correction（RCMC） method,the processing procedure of algorithm is simplified and imaging efficiency is also improved.Simulations validate the proposed algorithm to process the parallel airborne bistatic squint SAR data.