| Fully polairmetric radar system has already been a popular research topic recently.It is hoped that polarization of electromagnetic wave can be used to expand the dimension of information received the radar system to improve the signal to noise ratio.Polarimetric scattering modeling and characterization are the basic tasks in the research of aerial target detection.In this thesis,different numerical simulations of polarimetirc scattering have been carried out based on combined field integral equation.Because of the intensity of cross-polarization scattering is much lower than the co-polarization scattering,the scattering matrix of a simple reflector has been analyzed.The condition of strong cross-polarization scattering has been obtained.The polarimetirc scattering characteristics of a new polarimetric scattering calibration reflector,stealth and non-stealth aircrafts and two typical unmanned aerial vehicles are important parts of this thesis.This thesis includes ISAR images of a composite target which is composed of different reflectors and two unmanned aerial vehicles.The differences of cross-polarization image and co-polarization image reflects that the variance of polariemtric scattering of geometrical structures.The one and two dimensional super-resolution imaging algorithm based on fully polarimetric echo model are used to extract the scattering centers of an unmanned aerial vehicle.The scattering characteristics of dihedral reflectors which are in free space and above sea are also analyzed.Finally,using the positions of the scattering centers extracted before,the scattering matrices are obtained.Based on the classical optimal polarization theory,thesis investigates the polarimetric power response of these centers.According to the analysis of polarimetric power response,the final conclusion is that the polarimeric radar can improve the performance of target detection. |
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