基于调频傅里叶变换的高速目标ISAR距离像算法

在大时宽带宽线性调频(LFM)体制高分辨逆合成孔径(ISAR)雷达中,目标高速运动将引起严重的回波多普勒色散,如果不消除该影响则不能正确成像。针对该问题,设计了一种通过调频傅里叶变换对目标脉内运动参数进行估计,补偿回波脉内走动得到目标距离像的方法。该方法首先估计脉内运动参数,初步补偿脉内走动,然后估计运动轨迹进一步精确补偿脉内走动,补偿脉内走动后通过包络对齐消除脉间走动,得到目标距离像。算法的主要过程在脉冲重复周期内进行,可以满足实时成像和参数估计的需求。

ISAR Range Imaging Method of High-Speed Targets Based on Chirp-Fourier Transform

In the high resolution radar system with large time-bandwidth LFM signal,the high speed of target will cause serious Doppler dispersion. In order to get correct imaging result,the Doppler dispersion must be eliminated. A novel range imaging method based on the chirp-Fourier transform is proposed,which can estimate the motion parameters of intra-pulse and compensate the intra-pulse motion to get the correct range profile. The method firstly estimates the intra-pulse motion parameters and preliminary compensate the motion,and then estimates the motion trajectory to further compensate the motion. After the intra-pulse compensation it can get the correct range profile by envelope alignment. The main parts of the algorithm are handled in the pulse repetition period,so it can meet the demand of real-time imaging and parameter estimation.