基于频域CLEANWigner-Ville分布中交叉项的抑制
Crossterm suppression in Wiger-Ville distribution based on CLEAN in frequency
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摘要: 针对ISAR飞机成像中出现的多分量线性调频(chirp)信号,该文提出一种基于频域CLEAN的信号分解方法,将其分解成多个单分量chirp信号,然后分别计算每个单分量的Wigner-Ville分布(WVD),以此来抑制此多分量信号WVD中的交叉项,与已有的chirp信号分解方法相比,该法减少了待估计参数的个数,使得计算更加简单,并能保证信号各分量正确的强度及时频变化特征。经过处理后的信号的WVD,保持了WVD高时频分辨率的特点,而交叉项得到了很好的抑制。实验表明,该方法应用于实测数据,成像质量明显提高了。Abstract: With respect to multicomponent chirp signals appeared in ISAR imaging, a new signal decomposition method based on CLEAN in frequency domain is proposed to suppress crossterms in Wigner-Ville Distribution (WVD), in which the multicomponents are first decomposed and then WVD of each decomposed one is computed. Compared with other chirp decomposition method available, the method presented here not only reduces the number of parameters to be estimated, which simplifies the computation, but also keeps the correct signal features. As shown in the experiment, a clearer time-frequency distribution with high time frequency resolution and greatly suppressed crossterms can e obtained, and the ISAR imaging quality is improved greatly.
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