Study On Ocean Modeling, Imaging And Along-Track InSAR

In recent years, the ocean remote sensing by spaceborne SAR is becoming reality, stable remote sensing data can be obtained by various spaceborne SAR sensors, which has aroused deep attention from authorities and scholars to study the relative thories and data interpretation methods. This dissertation focuses on SAR ocean sensing and systematicly discusses the ocean model, imaing and along-track InSAR using simulation methods, and introduces a full simulation link from the ocean surface model, the ocean scattering model, the spaceborne SAR raw signal simulation of ocean scene, ocean imaging, to the along-track InSAR for current measurements.The interaction between the electromagnetic wave and the ocean surface has to be taken seriously in modeling ocean, a proper ocean surface model and an accurate ocean scattering model need to be formulated. The first problem takes into account the ocean wave components and the ocean dynamics. Two-scale ocean surface model is a promising one. In the model, the ocean wave is separated into small scale wave and large scale wave, which is depicted by ocean wave spectra and fractal ocean surface model respectively. The Kirchhoff approximation method based on facets is adopted to reflect the electromagnetic-ocean surface interaction. An explicit formulation of backscattering coefficient can be obtained by the framework of the facet approximation, the Kirchhoff approximation method, and the Bragg dominant scattering mechanism.As an application of ocean model, a spaceborne SAR raw signal simulation and imaing and an along-track InSAR simulation for current measurements is carried out. In the first simulation, the raw signal simulation model of dynamic scene based on time domain is proposed. This simulation procedure reconstructs ocean surface, computes the backscattering coefficient and generates raw signal at every azimuth slow time. The second simulation is realized in the SBRAS (Spacebore Radar Advanced Simulator, a SAR InSAR and GMTI simulation system for land applications) by designing along-track formation.