一种新的基于极坐标格式的快速后向投影算法
doi: 10.3724/SP.J.1146.2013.00613
A New Fast Back Projection Algorithm Based on Polar Format Algorithm
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摘要: 快速分级后向投影算法(Fast Factorized Back-Projection Algorithm, FFBPA)研究了BPA中的冗余计算，通过子孔径划分，在极坐标系下将信号逐级相干积累成像，该方法避免了BPA中每个图像点的重复性全孔径搜索过程，大幅减少了计算量。然而多级插值操作加剧了误差积累，减少分级次数又影响算法效率。为解决这一矛盾，该文结合极坐标格式算法(PFA)提出了一种新的多级迭代快速BP成像算法，并将算法拓展应用到曲线轨道，多模式SAR中。分析表明，该文方法与FFBPA相比更高效。最后通过该文算法与FFBPA的星载0.1 m超高分辨率聚束SAR成像进行仿真实验对比，验证了该方法的优越性。
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关键词:
- 合成孔径雷达 /
- 快速分级后向投影算法(FFBPA) /
- 极坐标格式算法(PFA) /
- 曲线轨道 /
- 多模式
Abstract: The redundant calculation in Back-Projection Algorithm (BPA) is studied in Fast Factorized BPA (FFBPA). By dividing sub-apertures and accumulating signal coherently in polar format coordinate, image with high resolution is obtained. The progress of repeatedly searching every signal in full aperture for every pixel is avoided in FFBPA, thus the amount of computation is reduced. However, multi-stage interpolation operation increases the error accumulation. Combining with the original Polar Format Algorithm (PFA), a new multi-stage iteration Fast PFA is proposed, and it is modified to process data in curve orbit and multiple modes SAR. Analysis indicates that the proposed algorithm is more efficient than FFBPA in practice. Comparison of simulation results of spaceborne spotlight SAR with very high resolution (0.1 m) processed by the proposed algorithm and FFBPA verifies the superiority of the new algorithm over FFBPA. -
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