基于全极化UAVSAR图像的海浪斜率反演方法研究

发布时间：2018-05-13 16:13

本文选题：海浪斜率 + UAVSAR　；参考：《中国海洋大学学报(自然科学版)》2017年12期

【摘要】：利用L波段Uninhabited Aerial Vehicle Synthetic Aperture Radar(UAVSAR)全极化数据,对成像海域海浪斜率的反演进行了研究。其中,沿SAR图像方位向海浪斜率是通过Krogager分解右旋和左旋圆极化相位差方程所提取的极化方向角,并利用该极化方向角的偏移量进行求解。而在求解海浪沿距离向的斜率的过程中,本文则选取了平均散射角(α角)、一致性参数、极化相干矩阵对角元素T22/T11、同极化比四种极化特征参数,并基于Bragg共振散射模型,对这四种极化特征参数的近似表达式进行了理论推导,通过分析发现这四种极化参数都是入射角的单调函数,从而使得利用这四种极化参数拟合求解距离向海浪斜率成为可能。本文中选取37景UAVSAR海浪图像,采用极化方向角及其他四种极化参数分别对海浪方位向和距离向斜率进行了拟合反演,并通过反演所得海浪斜率谱进一步计算出感兴趣海域海浪的波长、周期、传播方向、斜率均方根、有效波高等参数,将所得结果与National Data Buoy Center(NDBC)提供的浮标数据进行了对比。通过对反演结果进行统计分析发现:T22/T11、一致性参数的所得结果较好,同极化比次之,α角稍差;另外,从计算的复杂程度来说,T22/T11、一致性参数、同极化比较之α角简单,不需要复杂的极化分解。
[Abstract]:In this paper, the inversion of wave slope in the imaging sea area is studied by using L-band Uninhabited Aerial Vehicle Synthetic Aperture Radarn UAV SAR full polarization data. The wave slope along the azimuth direction of the SAR image is extracted by the Krogager decomposition of the right-handed and left-handed circular polarization phase difference equations and solved by the offset of the polarization direction angle. In the process of calculating the slope of ocean waves along the distance, the average scattering angle (伪 angle, consistency parameter, polarization coherence matrix diagonal element T22 / T11, and the same polarization ratio) are selected in this paper, and based on the Bragg resonance scattering model, four polarization characteristic parameters are selected. The approximate expressions of these four polarization characteristic parameters are theoretically deduced. It is found that the four polarization parameters are monotone functions of the incident angle, which makes it possible to use these four polarization parameters to fit and solve the distance slope of ocean waves. In this paper, 37 UAVSAR wave images are selected, and the azimuth and distance slope of ocean waves are fitted by polarization direction angle and four other polarization parameters, respectively. The wave wavelength, period, propagation direction, slope mean square root, effective wave height and other parameters are further calculated by inversion of wave slope spectrum. The results are compared with the buoy data provided by National Data Buoy Center. Through the statistical analysis of the inversion results, it is found that the consistency parameter has better results, the same polarization ratio is second, and the 伪 angle is slightly worse. In addition, in terms of the complexity of the calculation, T22 / T11, the consistency parameter, and the 伪 angle compared with the polarization are simple. There is no need for complex polarization decomposition.
【作者单位】：中国海洋大学信息科学与工程学院;
【基金】：国家自然科学基金项目(41376179) 国家自然科学基金委员会-山东省人民政府联合资助海洋科学研究中心项目(U1406404)~~
【分类号】：P714.1

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