Impacts of Ionospheric Scintillation on the BIOMASS P-Band Satellite SAR
Impacts of Ionospheric Scintillation on the BIOMASS P-Band Satellite SAR
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DOI：
10.1109/tgrs.2013.2255880
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发表时间：
2014-03
影响因子：
8.2
通讯作者：
N. Rogers;S. Quegan;Jun Su Kim;K. Papathanassiou
中科院分区：
文献类型：
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作者：
N. Rogers;S. Quegan;Jun Su Kim;K. Papathanassiou
欧洲航天局正在对一种名为生物量的低地球轨道极化合成孔径雷达进行研究，以提供森林生物量和树木高度的全球测量。由电离层不规则性引起的合成孔径上的位相闪烁会降低脉冲响应函数(IRF)并引起斜视，其时间变化会导致重复通过干涉测量中的去相关。利用宽带闪烁模型对基线生物量系统配置的一系列条件下的这些影响进行了模拟，该模型预测，对于黎明-黄昏轨道，除了在高太阳黑子活动情况下的北美高纬度地区外，林区上空的闪烁影响在所有条件下都可以忽略不计。在这一区域，在太阳活动中值至北树线(~70°地磁)的90%可信区间内，单视红外激光雷达的平均积分旁瓣比(ISLR)和峰值旁瓣比(PSLR)分别优于0和-5分贝。预计平均3分贝分辨率将下降10%，IRF峰值的平均绝对方位漂移最高可达2米，在太阳黑子数较高时增加到5米。在黎明和黄昏两侧也发现了类似的值，而林线以下纬度的季节变化可以忽略不计。重复通过干涉图像对在中等太阳黑子条件下保持高达50°N的相干性。四视处理将ISLR和PSLR提高了几个分贝，但由于具有不同随机方位移位的图像的非相干平均，导致3dB分辨率显著下降。
The European Space Agency is conducting studies for a low-earth orbiting polarimetric synthetic aperture radar called BIOMASS to provide global measurements of forest biomass and tree height. Phase scintillation across the synthetic aperture caused by ionospheric irregularities can degrade the impulse response function (IRF) and cause squinting, and its temporal variation can cause decorrelation in repeat-pass interferometry. These effects are simulated for a range of conditions for the baseline BIOMASS system configuration using the Wideband model of scintillation, which predicts that for a dawn-dusk orbit, impacts of scintillation over forest regions are negligible under all conditions except at high latitudes in the North American sector under high sunspot activity. In this sector, single-look IRFs have mean integrated sidelobe ratios (ISLRs) and peak sidelobe ratios (PSLRs) better than 0 and -5 dB, respectively, at 90% confidence interval under median solar activity up to the northern tree line ( ~ 70° geomagnetic). Degradation in the mean 3-dB resolution of up to 10% is predicted, with mean absolute azimuth shifts of the IRF peak of up to 2 m, which increases to 5 m at high sunspot number. Similar values are found for the dawn and dusk sides, and seasonal variations are negligible for latitudes below the tree line. Repeat-pass interferometric image pairs maintain coherence up to 50 ° N under median sunspot conditions. Four-look processing improves the ISLR and PSLR by several decibels, but causes significant degradation of the 3-dB resolution due to incoherent averaging of images with different random azimuth shifts.