一种新的频域带宽合成的斜视高分辨SAR成像方法

针对步进频信号带宽合成存在相位跃变的问题,提出一种新的频域带宽合成方法.由于雷达与目标相对运动是导致合成频谱相位跃变的主要原因,因此,该方法根据雷达与目标相对运动的斜距形式对各个子脉冲引入的相位误差进行补偿.文中采用了改进的步进频数据处理方法,首先对子频带进行脉冲压缩,然后进行带宽合成、二次距离压缩及徙动校正,从而避免了子频带进行徙动校正后对带宽合成的影响.在完成带宽合成后,采用调频变标(Chirp Scaling,CS)算法得到了斜视二维高分辨合成孔径雷达(Synthetic Aperture Radar,SAR)图像.为了证明该方法的有效性,给出了仿真及实测数据的处理结果.由理论仿真与实测数据的对比分析可知,该方法有效地实现了窄带步进频信号合成宽带信号.

Squinted high resolution SAR based on the frequency synthetic bandwidth

Due to the problem of high grating-lobe caused by phase discontinuity for frequency bandwidth synthetic, a new method of frequency synthetic bandwidth is proposed. The cause for phase discontinuity of frequency spectrum is the relative motion between radar and scatterers. The phase error for every sub-pulse according to different forms of the slant range between radar and scatterers is compensated by this method. A new approach is put forward for step frequency signal processing after the frequency band is synthesized. First, the pulse is compressed and frequency band is synthesized. After the frequency band is synthesized, the second range compression and the range migration correction are implemented. Then, phase discontinuity due to the corrected range migration correction is avoided. Finally, Chirp Scaling is applied to obtain the squint two-dimension high resolution SAR (Synthetic Aperture Radar, SAR) image. In order to identify the availability of this method, simulation results are shown in the paper. Experiments on raw data and simulation show that the wide-band signal could be synthesized by the narrow-band stepped signal.