Study Of InSAR Phase Unwapping Based On GAMMA Software

Taking the phase information extracted from the plural data acquired by SAR as its source, Interferometric Synthetic Aperture Radar (InSAR) is developed to obtain the terrain information and variety details. It is also a main profile of satellite SAR application. Compared with traditional remote sensing technique, InSAR has quite a lot of advantages such as large coverage, high spatial resolution, high elevation accuracy, and the capability of working at all time and under all-weather conditions. It is the most effective method to acquire the 3D Digital Elevation Models (DEM). InSAR has evolved to satisfy a variety of applications for both civilian economy and military. This technology has attracted world-wide attention and research.In this paper,the main principle and data processing flow of InSAR are introduced, especially in phase unwrapping.Phase unwrapping is one of the most important steps of this flow, and also the main source of error. When you want to fetch Digital Elevation Model or the deformation of earth surface, you will find that their precision depends on successful phase unwrapping. Whether or not to do phase unwrapping efficiently and accurately has become a bottleneck of InSAR technological development. Although there are many algorithms, but not a generic algorithm. In this paper, at home and abroad on the current phase unwrapping algorithm is summarized. Branch-cut method, quality quided path following method, mask cut method, Flynn minimum discontinuity and Least square method are discussed in this paper. We Summed up their advantage and disadvantage and scope of application.The literature about research on InSAR phase unwrapping are numerous at home,but most of them based on simulated data. It more difficult to deal with real data of InSAR. .Using GAMMA software to deal with three scenes of image data in Bam area of Iran, it successfully obtained the results of phase unwrapping about two pairs of image .The data were acquired by Advanced Synthetic Aperture Radar of ESA's ENVISAT-1 satellite. The results of the two groups data about phase unwrapping were compared and analyzed by using MATLAB. It also identified which one is better and the reasons for this result.Finally, we summed up the research article. The inadequacies and future direction of work of this paper are pointed out. We also prospect the future of InSAR technology in our country.