Total zero Doppler steering - A new method for minimizing the Doppler centroid
Total zero Doppler steering - A new method for minimizing the Doppler centroid
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DOI：
10.1109/lgrs.2005.844591
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发表时间：
2005-04-01
影响因子：
4.8
通讯作者：
Krieger, G
中科院分区：
文献类型：
--
作者：
Fiedler, H;Boerner, E;Krieger, G
本文提出了一种用于星载合成孔径雷达（SAR）系统偏航和俯仰控制的新方法，称为全零多普勒控制。新方法将多普勒中心降低到理论上为0 Hz，与感兴趣的距离位置无关。残余误差仅是由于指向不准确或由于在执行总零多普勒导向法的近似。这封信将新方法与目前使用的方法进行了比较。姿态角和残余多普勒中心频率的计算和描述的TerraSAR-X的参数，新的方法将实施和使用的示例。新方法提供了许多优点。低残留多普勒中心和范围内多普勒中心变化的减少允许更准确的多普勒中心估计。由于低残留多普勒中心，可以减轻合成孔径雷达（SAR）的处理，因为距离单元迁移减少和多普勒频率低。这便于使用非常有效的处理算法，该算法基于对于低多普勒频率而言质量更好的近似。新方法将进一步优化交叉跟踪干涉测量的SAR图像对的方位频谱的重叠。低多普勒质心也将减少干涉相位上的配准误差的影响。此外，扇形校正ScanSAR处理中的减轻由于低变化的多普勒质心的范围。
This letter presents a new method, called total Zero Doppler steering, to perform yaw and pitch steering for spaceborne synthetic aperture radar (SAR) systems. The new method reduces the Doppler centroid to theoretically 0 Hz, independent of the range position of interest. Residual errors are only due to pointing inaccuracy or due to approximations in the implementation of the total zero Doppler steering law. This letter compares the new method with currently applied methods. The attitude angles and the residual Doppler centroid frequencies are calculated and depicted exemplarily for the parameters of TerraSAR-X, for which the new method will be implemented and used. The new method provides a number of advantages. The low residual Doppler centroid and the reduced variation of the Doppler centroid over range allow a more accurate Doppler centroid estimation. Due to the low residual Doppler centroid, the synthetic aperture radar (SAR) processing can be alleviated, since the range cell migration is reduced and the Doppler frequencies are low. This facilitates the use of very efficient processing algorithms, which are based on approximations whose quality is better, for low Doppler frequencies. The new method will furthermore optimize the overlap of the azimuth spectra of SAR image pairs for cross-track interferometry. Low Doppler centroids will also reduce the impact of coregistration errors on the interferometric phase. Furthermore, scalloping corrections in the ScanSAR processing are alleviated due to the low variation of the Doppler centroid over range.