Ship Wakes Modeling And Researches On Its Related Electromagnetic Methods

Recently, the researches both on electromagnetic (EM) scattering analysis of shipwake and submarine internal wave and on the corresponding target detection havereceived considerable attentions, and they are one of the important research areas inradar remote sensing and ocean military target detective. Therefore, the sea surfacemodeling, including wind-driven surface, ship wake and submarine internal wave hasbeen summarized in this paper, the EM simulation solver for the ship wake and internalwave has also been studied. Based on the simulation data, the remote sensing imagesunder the different ocean states have been analyzed. The main contribution of this thesiscan be summarized as:1. the basic theory of sea geometric modeling has been introduced. Based on thehydrodynamics, the general mechanism from sea surface ship wake (Kelvin wake),wind-driven sea surface and submarine internal wave have been summarized. Inconsideration of realistic sea states, the composite sea model has been composedof wind-driven surface and ship wake accoding to the geometry linearsuperposition.2. in order to solve the problem of the electrical large-scale sea surface with highsimulation accuracy, the physical optic (PO) and a new improved Kirchhoffmethod were proposed in this paper. Instead of plane incident wave, the taperedincident wave was introduced to reduce the boundary effects in computationalelectromagnetics. And the Multi-Kirchhoff approximation method, where the seasurface was divided into several small pieces, was applied to solve the large-scalescattering problems. The computational costs were greatly reduced withoutaffecting the accuracy on calculation of the general case.3. based on the simulated data, the synthetic aperture radar (SAR) images for thosesea surface models have been studied. The radar echo and the remote sensingimages in L-band and C-band for the proposed sea surfaces has been simulatedand analyzed under some necessary techniques. Also, the detective mechanism forthe internal wave was introduced. From the SAR grayscale image obtained by our simulation, the possibilities of target detective based on the SAR imagecharacteristics have been revealed in this paper.Some simulations and researches on the geometric modeling, electromagneticscattering simulation and the imaging of target detection, have been done in this paper.Some different sea states corresponding to the different moving target parameters,such as target speed, geometric size, draft and dive depth, have been studied, and theirscattering characteristics solved by PO and multi-KA were obtained and borrowed toanalyze the SAR images. As the basic research works, the researches afore-mentionedare valuable in ocan microwave remote sensing and ocean target detective inengineering.