Kelvin尾迹SAR多视向的成像仿真

利用船只Kelvin航迹模型、海面波模型和二尺度微波散射模型,提出了船尾迹多视向的成像仿真技术,并首次在二维空间中从不同视向仿真船尾迹的SAR图像。结果表明,当雷达视向与船只航向平行时,横波成像明显;当雷达视向与船只航向垂直时,扩散波成像明显;当雷达视向与船只航向有个夹角时,会出现一臂亮一臂暗的现象,这一现象取决于两臂尖波的传播方向与雷达视向的夹角,传播方向与雷达视向越接近平行的波越容易被雷达观测到,从而形成亮臂。仿真结果还得出另外一个结论:船只航向与雷达视向越接近垂直,两臂张角越小。仿真结果和实际的多幅ERS-SAR图像所观测到的结果是一致的。该模型可以有效地模拟Kelvin尾迹SAR多视向成像。

The simulation study of Kelvin ship wake imaging by multi-look direction SAR

Based on the Kelvin ship wake mode,the ocean wave mode and the two-scale mode for electromagnetic scattering from rough surfaces,we propose a new method of simulation for Kelvin ship wake imaging by multi-look direction SAR.We have simulated SAR images of the ship wakes from different look directions in 2-D space firstly.The results show that the transverse waves can be viewed clearly when the radar look direction is parallel to the ship's track direction,while the divergent waves can be viewed clearly when the radar look direction is perpendicular to the ship's track direction.When the radar look direction is neither perpendicular nor parallel to the ship's track direction,Kelvin arms are imaged as a bright line and a dark line according to the relationship between spread direction of crest waves and ship's track direction.The waves whose track direction is more parallel to the ship's track direction can be imaged as a brighter line.Moreover,the simulation results also draw this conclusion another,when radar look direction is more near perpendicular to the ship's track direction,the angle between two Kelvin arms is smaller,because in these circumstances,the stern wave scattering cross-section is as large as bow wave.It is show that the simulated results agree quite well with the ERS-SAR images.