Tomography Three-dimensional Sar Imaging Algorithm

The three-dimensional imaging systerm of Synthetic Aperture Radar(SAR) has not only inherited all the advantages of traditional two-dimensional SAR, such as all-time, all-weather and high-resolution, but also avoided the ambiguity problems in two-dimensional imaging caused by the projection from the three-dimension space to two-dimensional scene, and achaived a direct localization of all scattering three-dimensional contributions. With the development of SAR imaging technology and the expanding of its application, three-dimensional imaging technology has become an important development direction of the radar imaging.3-D SAR imaging technology based on tomography theory combines the two-dimensional SAR images obtained from different track heights to achieve focusing in height direction and to generate a three-dimensional SAR image. Differ from the traditional InSAR technology, tomography SAR can resolved the misinterpretations in SAR images caoused by lay-over and fore-shortening effects, it can truly achieve the three-dimensional imaging and does not require extra complex flight trajectory controls, so tomography SAR has great research value in the field of radar imaging. However, since there are still many deficiencies in the tomography SAR imaging techniques, several researches on the principle and efficient algorithms of tomography SAR imaging processing has been done in this dissertation.This paper will first take CT technology in medicine as an example to introduce the tomographic theory, then according to the signal properties and imaging model of tomography SAR to analyze CT's application in three-dimensional SAR imaging, consides the tomoprahic imaging as an extension of well known two-dimensional w-k processing technique to three dimensions. Refering to solution of focusing problem in azimuth in two-dimensional imaging by one-dimensonal sensor trajectory in azimuth, a conventional SAR configuration is proposed to achieve elevational focusing problem, and demonstrate the principle of tomography SAR three-dimensional imaging Afterward, Main discussions are focused on the key technologies, such as the image registration and the third-dimensional focusing. Finally, to deal with the fact that the results carried out in the method based on Fourier Transformation is not satisfactory, more efficient algorithms for tomographic processing of multibaseine SAR data based on modern spectral estimation are proposed to improve the imaging resolution and verify the algorithms performance in experiments, and finally addresses the experimental realization of ground-based tomography SAR system.