The Research For Phase Unwrapping Of Interferometric Synthetic Aperture Radar

One of the most basic applications of interferometric synthetic aperture radar (InSAR)measurement system is to obtain the ground elevation, and the other extended applications are based on the basic elevation information. The accuracy of the ground elevation information is determined by the phase unwrapping. Therefore, it is necessary to carry out a detailed research on the key technology of InSAR signal processing.In this paper, we have carried out research on the interference processing of SAR, and mainly studied the phase unwrapping problem of height inversion in InSAR. First of all, the process of data analysis and processing of InSAR is briefly described, and several important steps are as following:image registration, ground effect removal, phase noise filtering,winding phase unwrapping, geographic information of encoding, etc.. And then, the process of elevation inversion is performed on the SARscape by data of ENVISAT ASAR, and the position and the importance of the phase unwrapping in the InSAR process are reflected. The traditional phase unwrapping algorithm is introduced in detail, and the relative theory is deduced, which is the theoretical basis for the improvement and innovation of the algorithm.To solve the problem that Quality map method must be sorted, and when the amount of data is large, the relative cost of time is high, a Quality map method based on heap sort is proposed.Compared with traditional Quality map method, it can make good optimization of the sorting time and reduce the time complexity of the algorithm, so the algorithm has better adaptability. the experimental results also verify the correctness and efficiency of the Quality map method with heap sorting algorithm in the phase unwrapping problem.To overcome the shortcomings of the easy to form a separate island without unwrapping,which is caused by the traditional path integral phase unwrapping method based on the residual points, a new algorithm of InSAR Phase Unwrapping based on the traditional path integral phase unwrapping and quality map method is proposed. Simulation and experimental data processing results show that the proposed algorithm can not only overcome the shortcomings of the branch cut method, which can not get the complete solution,but also surmount stop the diffusion of phase unwrapping error caused by the quality map method.The method can effectively deal with the requirements of large winding phase unwrapping.For traditional Goldstein's branch cut method, residual path integral phase unwrapping method based on branch cuts is placed unreasonable. and obtaining path which easily to form a plurality independent island of unwrapping, and the whole length of the branch cuts is not very short. This paper presents an optimization branch tangent set of interference synthetic aperture radar phase unwrapping method. Firstly, introducing the concept of "closer" to the interferometric phase of pretreatment, most of the neighborhood can form comprehensive polar residues. Then through the shortest path connection using ant colony algorithm to solve the residuals. This method can not only effectively reduce the overall length of the branch cuts,but also significantly reduced the number of closed areas. The experimental results show that this method can realize the optimization of the branch cut set and has certain advantages on precision in phase unwrapping.