对比度最优自聚焦(COA)算法是一种计算量相对较小的自聚焦算法,在高波段及L波段SAR中得到了成功应用。但对于工作在P波段的超宽带SAR(UWB SAR),由于杂波噪声干扰严重,给COA算法的应用带来了较大的困难。文中针对UWB SAR这一特点,提出了一种有效减小杂波对对比度干扰的方法,通过改造对比度评价函数、选择信噪比较强的方位线、对方位压缩后的图像低通滤波、并剔除偏差较大的估计值等方法,有效地提高了COA算法在UWB SAR中的性能。实际UWB SAR数据的补偿结果表明了该方法的有效性。

Unlike synthetic aperture radar(SAR) operating on high band, there exists very strong clutter and noise in ultra-wide Band SAR (UWB SAR) working on UHF/VHF band, which makes it difficult for the application of contrast optimization autofocus (COA) algorithm in UWB SAR. The strong clutter sometimes would make the image contrast cannot really reflect whether targets focus or not. The effects of the COA algorithm are decided by minishing the interference of clutter somewhat. In this paper, some techniques are used to overcome the disadvantages of strong clutters and the results of real UWB SAR data show the validity of the improved COA.

TN957.52