Interferometric Test Using Domestic GF-3 SAR Satellite

Synthetic Aperture Radar(SAR)is an advanced radar system using image processing technology to synthesize large virtual antennas.It has all-day and all-weather working ability,and can obtain high-resolution images of ground targets.It was first used in military field.With the rapid development of remote sensing technology,it has gradually become one of the important tools in the field of microwave remote sensing.In the past two decades,SAR has been widely used in geological research,fine resolution mapping and other remote sensing applications.With the development of SAR,Interferometric Synthetic Aperture Radar(InSAR)technology was proposed.Researchers can extract surface information and elevation change information from the interferometric phase information of radar electromagnetic wave using InSAR technology.It also greatly expands the application field of SAR.Compared with stereophotogrammetry,the digital elevation model(DEM)of image coverage area obtained by InSAR technology can obtain higher ranging accuracy.Compared with the developed countries such as the United States and Germany,China is still in the preliminary stage of development in this technical field.As the first one-meter resolution C-band multipolarization synthetic aperture radar in China,the GF-3 satellite launched in August 2016 has the capability of interferometric imaging,but the research on interferometric processing of GF-3 satellite is still less,and the applicability of typical algorithms of each key step needs to be verified urgently.Due to the complexity of InSAR data processing process,many research institutions all over the world have developed their own InSAR processing software for scholars to use,such as GAMMA-SAR software,Earthview software,Doris software,etc.ENVI,one of the most famous remote sensing image processing software,has also added SARScape module for SAR data processing.Doris software is a set of open source,free,cross-platform processing software,which can realize the whole process of InSAR data processing,and provides a variety of alternative algorithms for some key steps.Because of its powerful function and strong independence of processing module,it has attracted the attention and use of many experts and scholars.At the same time,because of its open source advantages,software iteration is faster.However,the software has no graphical user interface and operates mainly on the command line,which leads to the failure of installation and difficulty of operation for beginners,which greatly limits the application scope of the software.In view of the above problems,the main work of this study is as follows:(1)Explained the principles of InSAR elevation measurement and deformation measurement in detail.Analyzed the calculation steps and characteristics of several commonly used algorithms,which provides a theoretical basis for subsequent application research.(2)On Windows platform,W-Doris software is developed based on the environment of QT+MinGW,which completely remedies the defects of Doris software such as command line operation,no graphical interface,and the inability to view the experimental results.The main functions of the software include generating template files,reading images,interferogram generation,filtering and unwrapping,geocoding,DEM product generation,etc.At the same time,the software provides text and picture viewers for viewing experimental results.(3)Realize the interferometry experiment using domestic GF-3 satellite.Using InSAR technology,DEM of the experimental area is extracted and its effective accuracy is evaluated.At the same time,the key steps of InSAR processing,phase filtering and phase unwrapping,are compared and analyzed by several commonly used algorithms.Among them,Goldstein filtering method has the best processing results,while filtering noise,it keeps the shape of phase waveform,the interference fringes are the clearest,the edges are smooth and the distinction is clear.The MCF method has good comprehensive performance and can achieve good results in different coherence regions,but the efficiency of the method is slightly lower than that of the region growth method.The results show that W-Doris software can realize all the functions of Doris software and provide GUI interface,which is more friendly to researchers;the data processing results of W-Doris software are correct and effective;and the capability of domestic high-resolution SAR satellite in interferometric imaging and interferometry is verified.