摘要
该文针对调频连续波合成孔径雷达(Frequency Modulated Continuous Wave Synthetic Aperture Radar,FMCW-SAR)在斜视模式下聚焦精度降低的问题,提出一种非线性尺度变换chirp-z成像算法。该算法利用回波信号在多普勒域中距离向的非线性特性,通过引入一个非线性调频信号对回波信号进行基于chirp-z的非线性尺度变换,降低距离压缩和距离徙动校正的误差,提高雷达图像分辨率。采用该成像算法对点目标模拟回波的成像结果与原始chirp-z算法相比,距离向分辨率和图像对比度得到提高,方位向分辨率保持不变。
A non-linear scaling chirp-z imaging algorithm for squint mode Frequency Modulated Contmuous wave Synthetic Aperture Radar （FMCW-SAR） is presented to solve the problem of the focus accuracy decline. Based on the non-linear characteristics in range direction for the echo signal in Doppler domain, a non-linear modulated signal is introduced to perform a non-linear scaling based on chirp-z transform. Then the error due to range compression and range migration correction can be reduced, therefore the range resolution of radar image is improved. By using the imaging algorithm proposed, the imaging performances for point targets, compared with that from the original chirp-z algorithm, are demonstrated to be improved in range resolution and image contrast, and to be maintained the same in azimuth resolution.
