| 捷变PRF技术在斜视聚束SAR中的应用 |
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| 引用本文： | 罗绣莲,徐伟,郭磊.捷变PRF技术在斜视聚束SAR中的应用[J].雷达学报,2015,4(1):70-77. |
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| 作者姓名： | 罗绣莲 徐伟 郭磊 |
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| 作者单位： | 1.(中国科学院电子学研究所 北京 100190)2.(中国科学院大学 北京 100039) |
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| 基金项目： | 自然科学基金青年基金(61401431)资助课题 |
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| 摘 要： | 该文关注一种新型的斜视聚束SAR模式，其采用捷变脉冲重复频率(PRF)技术来增加高分辨率成像时的距离向测绘带宽。聚束SAR利用波束旋转来增加方位向分辨率。然而，高分辨率和大斜视的成像要求会导致较大的距离单元徙动(RCM)。PRF固定不变(即接收窗固定)时，为了保证方位向数据获取时间内所有的回波脉冲能被完整接收，距离向测绘带宽对应的时间宽度必须小于接收窗宽度。为了消除RCM对测绘带宽的影响，该文将PRF沿着方位向时间连续地改变(捷变)，使得接收窗的变化与瞬时斜距的变化一致。首先推导了PRF的变化规律，然后利用一种改进的后向投影算法(BPA)对回波数据成像，最后通过仿真实验验证这种SAR模式及对应的成像算法。
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| 关 键 词： | 合成孔径雷达(SAR) 斜视聚束 捷变PRF 高分辨率 后向投影算法(BPA) |
| 收稿时间： | 2014-12-05 |
The Application of PRF Variation to Squint Spotlight SAR |
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| Luo Xiu-lian;Xu Wei;Guo Lei.The Application of PRF Variation to Squint Spotlight SAR[J].Journal of Radars,2015,4(1):70-77. |
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| Authors: | Luo Xiu-lian;Xu Wei;Guo Lei |
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| Affiliation: | 1.(Institute of Electronics, Chinese Academy of Science, Beijing 100190, China)2.(University of Chinese Academy of Science, Beijing 100039, China) |
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| Abstract: | This paper focuses on a novel squint spotlight SAR mode, where the PRI variation is employed to increase the range swath width, especially for high-resolution imaging. The spotlight SAR is developed to increase the azimuth resolution via steering the antenna beam to always illuminate the same area on the ground during the whole data acquisition interval. However, requirement of high resolution and large squint angle leads to large Range Cell Migration (RCM). Therefore, to ensure the scattered echoes along the azimuth to be completely received within the fixed reception window, the range swath has to be much narrower than the reception window. In order to increase the range swath, we can change the PRI along the azimuth to shift the reception window according to the variation of instantaneous slant range. This paper first derives the PRI variation scheme. Afterward, a modified time-domain Back-Projection Algorithm (BPA) is presented to implement the focusing. Finally, simulation results are given to validate the presented SAR mode and corresponding imaging processor. |
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