基于电磁模型的海面单双站SAR成像仿真

Mono/bistatic SAR imaging simulation of sea surface based on the electromagnetic model

为了得到更真实的海面SAR图像,将传统单双站海面SAR成像仿真中忽略的方位向上不同时刻散射回波的相干叠加和因相位的相互作用而产生的相干斑这一问题加以解决。根据海面不同时刻散射回波之间的相位差,将SAR提取出的海面各散射单元的散射系数引入相位差函数,进而将不同时刻散射回波相干叠加来获得新的海面SAR图像。此外,将分布式面元模型与SASS-II数据及SSA结果进行比较,验证了该模型的准确性,重点分析了风速、速度聚束调制、碎浪调制因素对单双站海面SAR成像的影响。仿真结果表明所提方法能够实现海面的精确模拟。

In order to obtain a more realistic sea surface SAR image, solves the problem of the coherent superposition of the scattered echoes at different moments in the azimuth direction and the coherent speckles caused by the phase interaction, which are ignored in the traditional mono/bistatic SAR imaging simulation of sea surface. According to the phase difference between the scattered echoes at different times on the sea surface, the scattering coefficient of each scattering unit on the sea surface extracted by SAR is introduced into the phase difference function, and then the scattered echoes at different times are coherently superimposed to obtain a new sea surface SAR image. In addition, the distributed surface facet model used in this paper is compared with SASS-II data and SSA results to verify the accuracy of the model, focuses on analyzing the influence of wind speed, velocity bunching modulation, and breaking wave modulation factors on mono/bistatic SAR imaging of sea surface. The simulation results show that the method can achieve accurate simulation of the sea surface.