Research On The Method Of Phase Unwrapping In Interferometric SAR

Taking the phase information extracted from the plural data acquired by SAR as its source, interferometric synthetic aperture radar is developed to obtain the terrain information and variety details. As the upgrade of 2D-SAR, InSAR technology has undergone rapid development and is being more and more mature. Distributed space-borne interferometric synthetic aperture radar is a novel radar system, which is the result of the combination of space-borne SAR and satellite formation flying technology. The satellites in formation cooperate with each other to fulfill terrain mapping. The successful application of InSAR in the satellite has enormously exalted the height-measuring ability of it. Because of the advantages such as precision in height-measuring, strong survival and anti-jamming ability, short cycle of manufacture and low cost, distributed space-borne InSAR height measuring system has become a hotspot of spaceflight remote sensing research. This thesis, with the distributed space-borne InSAR height measuring system as its background technology, is mainly about the systematic research the phase unwrapping, a key step in data processing of InSAR, especially the method of it on multi-baseline condition. This thesis centers around three aspects:1. Present a new method for removing flat earth effect. Under the interference of flat earth effect, the interferogram fringes tend to be over intensive which results in the difficulty of phase unwrapping. So the flat earth effect must be eliminated. And also the phase noises could affect the quality of interferogram so that they should be filtered after the removal of the flat earth effect.2. Research on the method about phase unwrapping of single-baseline InSAR and improvement. After many years of development, various methods of phase unwrapping has been created, each having its advantages and disadvantages as well. This thesis offers a brief introduction about these widely adopted methods and the improvement of them which enhances the precision or speed of unwrapping.3. Analysis of the method about phase unwrapping of multi-baseline InSAR. The distributed space-borne InSAR can not only improve saliently the accuracy of height-measuring, but also reconstruct the DEM of intricate terrain. This thesis carries out the methods for multi-baseline InSAR: Least Mean Squares and interactive method.