Research On Electromagnetic Scattering Modeling Method For Harbor Scene

Research on electromagnetic scattering characteristics of complex harbor scene is significant for the target identification,navigation and remote sensing of harbor,docks,etc.But there are many difficulties in the process of the study.First,the complex scene often contains a variety of different material objects and different properties of the background,which makes the modeling a very difficult task.Second,the size of the scene model is generally large,how to achieve rapid calculation is a difficult problem.In addition,the coupling between the environment and the target is complex,and the electromagnetic scattering characteristic analysis is more difficult.In this paper,based on the study of electromagnetic scattering of the complex target and rough surface,the electromagnetic scattering of the rough surface and target and the complex scene in the near shore are analyzed according to the multi-path theory.The paper mainly launched the research work from the following several aspects.Firstly,according to the real wharf scene,the typical port target(such as container,oil tank,tower crane,ship)is modeled.Then based on geometrical optics and physical optics method(GO-PO)and other complex targets electromagnetic scattering processing method,the electromagnetic scattering characteristics at different angles,frequencies and polarizations are analyzed.Secondly,the rough surface of asphalt,cement and sea surface are generated by linear filtering method,and the surface characteristics are analyzed.Based on the theory of electromagnetic scattering from rough surface,the electromagnetic scattering characteristics of cement surface and nearshore sea surface are analyzed.In particular,the influence of different dielectric constant and roughness on the electromagnetic scattering characteristics of cement surface and the effect of different angles and wind speeds on electromagnetic scattering characteristics of sea surface are studied.The study of the electromagnetic scattering from rough surface lays the foundation for the study of composite scattering from target and environment.Finally,according to the modified multipath model to solve the composite electromagnetic scattering problem,based on the idea of the four path model,the GO-PO method and the double scale method are used to calculate the direct scattering of the target and the rough surface respectively,according to the idea of dealing with multiple reflections in the GO-PO method,the coupling scattering between the target and the rough surface is dealt with the composite electromagnetic scattering from target and environment is calculated by a modified multipath model.The model is based on the idea of four path model.The direct scattering of target and rough surface are calculated separately by GO-PO method and the two scale method,according to the idea of dealing with multiple reflections in the GO-PO method,the coupling scattering between the target and the rough surface is disposed.Based on the multi path method,the composite electromagnetic scattering and the element field distribution of cement rough surface and oil tank,sea surface and ship are calculated and analyzed.Finally,the simplified model is built according to the real wharf scene,and the electromagnetic scattering characteristics of complex scene are discussed,especially the distribution characteristics of the element field under different angles and different wind speeds.