Multichannel HRWS SAR Imaging Based on Range-Variant Channel Calibration and Multi-Doppler-Direction Restriction Ambiguity Suppression
Multichannel HRWS SAR Imaging Based on Range-Variant Channel Calibration and Multi-Doppler-Direction Restriction Ambiguity Suppression
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DOI：
10.1109/tgrs.2013.2281329
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发表时间：
2014-07
影响因子：
8.2
通讯作者：
Shuang-xi Zhang;M. Xing;X. Xia;Lei Zhang;Rui Guo;Y. Liao;Z. Bao
中科院分区：
文献类型：
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作者：
Shuang-xi Zhang;M. Xing;X. Xia;Lei Zhang;Rui Guo;Y. Liao;Z. Bao
为了获得高分辨率宽测绘带（HRWS）图像，采用多通道方位合成孔径雷达（SAR）系统来解决高分辨率与低脉冲重复频率（PRF）之间的矛盾问题。本文针对多通道方位HRWS SAR成像系统提出了一种新的通道校准方法。在通道校准过程中，首先通过距离频域的粗校准处理来校正由增益相位误差和距离采样时间误差引起的通道之间的不匹配。然后，估计沿方位角基线测量误差。考虑到残余相位误差的距离方差，沿距离时域对数据进行分块处理，并对每个子块数据的误差进行估计。之后，沿着所有子块的相位误差估计值的范围进行拟合和滤波。然后使用它们的估计值来补偿随范围变化的相位误差。在信道校准之后，本文还提出了一种新的多普勒模糊度抑制算法，该算法消除了多普勒域中的模糊度分量。新提出的算法优于后多普勒模糊度抑制算法。利用工作在X波段的七通道方位角SAR成像系统采集的机载实测扫描合成孔径雷达数据，验证了新提出的通道校准方法和新的多普勒模糊度抑制算法的性能。
In order to obtain high-resolution wide-swath (HRWS) images, the multichannel in azimuth synthetic aperture radar (SAR) system has been adopted to deal with the contradiction problem between high resolution and low pulse repetition frequency (PRF). In this paper, a novel channel-calibration method is proposed for the multichannel in azimuth HRWS SAR imaging system. During the channel calibration, the mismatch between the channels, which results from the gain-phase error and the range sampling time error, is first corrected by the coarse-calibration processing in the range frequency domain. Then, the along azimuth baseline measurement error is estimated. Considering the range variance in the residual phase error, the data are processed in blocks along the range time domain, and the error of every subblock data is estimated. After that, a fitting and filtering is implemented along the range to the estimated values of the phase error of all subblocks. The range-variant phase error is then compensated using their estimated values. After channel calibration, this paper also presents a new Doppler ambiguity suppression algorithm which nulls the ambiguity components in the Doppler domain. The newly proposed algorithm outperforms the post-Doppler ambiguity suppression algorithm. The airborne real measured scan synthetic aperture radar data, which are acquired by a seven-channel in azimuth SAR imaging system with the system working at X-band, are utilized to demonstrate the performance of the newly proposed channel-calibration method and the new Doppler ambiguity suppression algorithm.