Research On Synthetic Aperture Radar Imaging Echo Simulation Of Typical Terrain Surface

As Synthetic Aperture Radar(SAR)is widely used in the national economy and the military,typical terrains of the SAR echo simulation research is getting more and more attention of the experts and scholars.Through the establishment of SAR echo simulation platform of typical terrains,we can effectively simulate the electromagnetic scattering characteristics of the terrain environment,which could provides an effective means of simulation for the analysis of electromagnetic scattering characteristics of terrains,ground targets reconnaissance identification and accurate positioning.This thesis studies electromagnetic scattering modeling method of terrains and airborne SAR imaging echo simulation from the rough surface scattering theory and the theory of airborne SAR.The main contributions include the following two aspects:1.The Integral Equation Method(IEM)of rough surface scattering approximation method is studied.According to the incident wave and the terrain have surface interaction,.IEM gives calculation expression of electromagnetic scattering about the rough surface.However,because the calculation of IEM under the relevant observation Angle has larger differences with measurement results,the Fresnel reflection coefficient and the compensation field of IEM are improved.The Advanced Integral Equation Method(AIEM)is introduced to the influences of surface roughness and the incident wave frequency in the Fresnel reflection coefficient and considers the influence of transmission wave under the lower surface in compensation field additionally.Through the improvement and of IEM,it makes that IEM can meet the demands for electromagnetic scattering practical modeling of the terrain environment.2.The IEM is applied to the electromagnetic scattering calculation of the complicated terrain environment by the coordinate transformation method of tilt modulation.We establish the electromagnetic scattering polarization SAR imaging platform of typical terrain environments under the form of point targets,which combined with the platform of airborne SAR echo simulation method.Among them,according to the condition of that strip SAR can be used in electromagnetic imaging characteristics analysis of the big scene and spotlight SAR can be used in accurate positioning of a particular area,this thesis studies the airborne stripe,spotlight SAR echo signal models,and the SAR echo simulation platform is set up according to the parameters selection method of the SAR system,and then selects Range Doppler imaging algorithm and SPECAN-RD algorithm to conduct imaging processings of echo signal under two kinds of working modes,so as to get the final polarization SAR imaging data of typical terrain environments.Finally,the paper selects the soil terrain in the form of point target and uses the above SAR imaging simulation platform to get its polarization SAR images,so as to further illustrate the effectiveness of the simulation about the airborne SAR platform.