针对LFM体制下ISAR雷达在低信噪比下对未知运动目标成像的难题,提出利用调频傅里叶变换的方法进行积累成像方法。在分析了脉间目标LFM回波信号特征的基础上,将目标回波信号在快慢时间域进行联合匹配和积累,通过能量积累后的目标位置估计搜索出目标的精确运动参数,并构建补偿函数实现目标运动补偿,从而获得低信噪比下的精确ISAR像。计算机仿真结果进一步表明了该方法能在低信噪比下稳健成像。

In order to obtain the unknown motion target imaging under low SNR in the LFM system, a new accumulation imaging method based on frequency modulated Fourier transform was proposed. Based on the characteristics of the target's LFM radar interpulse echo signals, the target's echo signals were jointly matched and accumulated in fast-slow time domain. Through the target position after energy accumulation, the target's accurate motion parameters could be searched out. After that, the compensation function was constructed to compensate the target motion, so as to obtain the accurate ISAR image. Computer simulation results showed that the proposed method could be robust under low SNR.