The Simulation Study of Kelvin Ship Wake Imaging by Multi-Look Direction SAR

摘要

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 the VV normalized radar backscattering cross-section (NRCS) 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 as a result of these circumstances gunpoint at the stern wave scattering cross-section is as large as bow wave. It's show that the simulated results agree quite well with the ERS-1/2 images.