SAR imaging of randomly corrugated surfaces with irregular grooves

Abstract

The theories of rough surface scattering are investigated through analysis of SAR imaging. Typically, scattering analysis based on the data averaged over surface realizations does not provide a detailed description of surface scattering phenomena. The advantages of imaging techniques for improving understanding motivate the use of high resolution imaging for studies of rough surface. Image domain can be helpful to provide more information on the physical behavior of scattering from rough surface. Different from the current point target imaging method, this paper focuses on the physical process of a SAR system from wave scattering to imaging in order to establish a connection between the scattering field and echo signal. SAR echo signal of target is considered as an inverse scattering problem for the reconstruction of target reflectivity, which is formed by the system response of the scattered fields. System simulation starts from simple objects to validate the proposed method and the imaging results not only provide information of target geometry also reflect the material properties of the object. Numerical surface of bistatic scattered field data are generated by random rough surface (Sastrugi surface) under tapered wave illumination. Sastrugi surface that is a corrugated surface with random number of ridges formed by natural forces and 1-D roughness is modeled along the forcing direction. The simulation results of coherent imaging offer the surface geometric information with corresponding parameter setting can be utilized in the reconstruction of surface profile and the retrieval of statistical parameters. Full polarization and bistatic angle can be used in novel system design and speckle analysis.