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基于多脉冲联合估计的SAR相位误差自聚焦算法 被引量:1
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作者 蒋锐 《系统工程与电子技术》 EI CSCD 北大核心 2016年第5期1039-1045,共7页
合成孔径雷达(synthetic aperture radar,SAR)是相干成像系统,所以接收信号相位的正确性决定了SAR图像的聚焦质量。利用自聚焦算法对SAR图像进行相位误差函数的估计及补偿是获得高分辨率,高质量SAR图像的关键步骤之一。其中,相位梯度自... 合成孔径雷达(synthetic aperture radar,SAR)是相干成像系统,所以接收信号相位的正确性决定了SAR图像的聚焦质量。利用自聚焦算法对SAR图像进行相位误差函数的估计及补偿是获得高分辨率,高质量SAR图像的关键步骤之一。其中,相位梯度自聚焦(phase gradient autofocus,PGA)算法运算量适中且鲁棒性好,被广泛应用于SAR自聚焦中。然而,PGA算法基于相位误差梯度值进行加权平均估计,相位差分的过程会引起噪声的积累,因此该算法对原SAR图像在方位数据域的信噪比要求较高。针对PGA算法存在问题,提出了基于多脉冲联合估计的相位误差自聚焦(phase error autofocus,PEA)算法。该算法采用了PGA算法的处理结构,并基于相位误差直接进行加权平均估计,可以在较低信噪比条件下正确实现SAR图像的自聚焦处理。仿真实验以及实测数据处理结果对比均表明,PEA算法可以获得优于PGA算法的自聚焦性能,且实际算法执行时间更短,更有利于算法实时处理。 展开更多
关键词 合成孔径雷达 相位梯度自聚焦 相位误差自聚焦 信噪比 多脉冲
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WLS filter for reducing atmospheric effects in spaceborne SAR tomography
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作者 董臻 孙希龙 +2 位作者 余安喜 孙造宇 梁甸农 《Journal of Central South University》 SCIE EI CAS 2014年第10期3889-3895,共7页
A new approach was presented to eliminate the atmosphere-induced phase error utilizing only the single look complex(SLC) synthetic aperture radar(SAR) image set. This method exploited the space-invariance characterist... A new approach was presented to eliminate the atmosphere-induced phase error utilizing only the single look complex(SLC) synthetic aperture radar(SAR) image set. This method exploited the space-invariance characteristic of phase error components contained in image pixels and estimates the phase error using the weighted least-squares(WLS) filter. Actually, this sort of method can be classified as autofocus algorithm which was generally applied in airborne SAR 2-D imaging to compensate the phase error introduced by airplane's nonideal motion. Real data processing, which is relevant to Honda center and Angel stadium of Anaheim test-sites and acquired by Envisat-ASAR during the period from June 2004 to October 2007, was carried out to evaluate this WLS estimation algorithm. Experimental results show that the phase error estimated from WLS filter is very accurate and the focusing quality along NSR dimension is improved prominently via phase correction, which verifies the practicability of this new method. 展开更多
关键词 synthetic aperture radar tomography 3-D image weighted least-squares AUTOFOCUS atmospheric effects
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