电离层对星载合成孔径雷达方位向分辨率影响的分析
doi: 10.3724/SP.J.1146.2007.00317
Study about Ionospheric Effects on Spaceborne SAR Azimuth Imaging
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摘要: 该文分析了天线实孔径尺寸、不同电离层谱以及电离层不规则体尺度等因素在电离层对星载合成孔径雷达(SAR)方位向分辨率影响中的作用。研究结果表明，保持星载SAR合成孔径长度不变，增加天线实孔径的尺寸会引起SAR方位向分辨率的退化，同时导致SAR方位向图像平滑。电离层的Kolmogorov谱对SAR方位向的影响较双参谱严重。电离层不规则体尺度远大于合成孔径的尺寸时，电离层对SAR方位向分辨率的影响可以忽略；在电离层不规则体的尺度减小到合成孔径的尺寸以下，但量级接近时，电离层的影响会导致SAR方位向分辨率的恶化。Abstract: In this paper, the effect of some factors such as the size of real antenna, different ionospheric spectra and the size of ionospheric irregularities on the azimuth resolution of Synthetic Aperture Radar(SAR) is investigated. The results showed that increasing real antenna aperture size but maintaining the equivalent aperture size of the SAR system will decrease the SAR images azimuth resolution, however, it can smooth azimuth image; Ionosphere with Kolmogorov spectrum affects the SAR azimuth imaging more seriously than that with two-parameter spectrum; When the irregularity scale is much larger than equivalent aperture size, the impact of the ionosphere on the SAR azimuth resolution can be ignored; However, when irregularity scale is smaller than equivalent aperture size but with close magnitude, the impact of the ionosphere will result in a substantial degradation of the azimuth resolution.
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