传统计算海面电磁散射的方法都是通过求集平均的方法来统计得到不同输入参数下海面总回波系数的均值曲线,并不需要具体的几何样本.随着合成孔径雷达以及雷达成像的发展,为了充分描述海面各点的分布特征,需要得到海面具体面元的散射结果,同时随着海面上方风速的增大,海面泡沫层的出现会对散射结果产生相当大的影响.本文采用海面模型面元化的思想,将海面散射的贡献面元化,同时考虑泡沫层对大入射角下散射结果的影响,计算了不同风速下海面的后向散射系数,并与实测数据做对比分析,验证了方法的准确性.
The traditional method of calculating electromagnetic scatterings from the rough sea surface, which does not need a geometrical sample of sea surface, considers mainly the total scattering echoes by average assembling of different incident parameters. With the development of synthetic aperture radar and radar imaging, it is important to fully describe the sea surface at every point, and to obtain the result of electromagnetic scatterings from the facets of the rough sea surface.Meanwhile, with increasing wind speed above the sea surface, the influence of the sea foam layer on the scatterings will increase. In this paper, the facet-model is considered, and taking into account the impact of the foam layer on the scatterings at a large angle incidence, the backscattering coefficient is calculated for different wind speeds; and the result of numerical simulation is compared with the experimental data to verify the accuracy of our method.