Improved SBAS Technology For Land Deformation Detection And Groundwater Application

Differential Synthetic Aperture Radar Interferometry(D-InSAR) had been applied to survey large range, all-weather, real-time surface slow deformation information. It has increasingly become an important technical means in monitoring ground deformation, ground fissure, seismic geological disaster. What’s more, it also greatly makes up for the traditional monitoring means such as GPS, leveling and other deficiencies. In recent years, Based on D-InSAR technology, the key techniques of differential synthetic aperture radar interferometry advanced techniques were deeply analyzed and studied in the dissertation such as PS-InSAR technology, small baseline subsets of D-InSAR Technology (SBAS), point differential interferometry (IPTA), which had been successfully applied in variation field,for instance, monitoring surface subsidence of city, crustal and earthquake deformation monitoring, landslide monitoring as well as the glacier variation field. However, with the application of these techniques to further expand, their arithmetic needs to be perfected in high-precision surveying.Based on key technology of D-InSAR, SBAS technology and IPTA technology were deeply analyzed and studied in the dissertation. In order to reduce the cost of data and improve deformation monitoring accuracy and efficiency, this paper presents the application of SBAS technology; In order to reduce the loss of coherence effect, PS-InSAR technology was proposed to achieve the PS point on the deformation monitoring; In order to improve the image processing efficiency, the vector data was used as an efficient data structures, which is namely IPTA data processing model; Based on the above, an integral terrain displacement detection method is proposed which not only can detect linear deformation, but also can detect periodicity and nonlinear deformation. In the study, Improved SBAS is not the two algorithms superimposed as SBAS and IPTA, but the algorithm improved. Interferometric phase noise reduction based on Dual Tree Complex Wavelet Transform is proposed; ASAR atmospheric delay phase correction is solved by using MERIS data. On the basis of theoretical research, the choice of Hebei District of Cangzhou was selected as the studied and experimental area. ENVISAT ASAR data were employed in the data processing. In order to verify the reliability of results, underground water level data in the monitoring wells and deformation monitoring result are used to compare. Deformation data and underground water level data are used to analysis of the regional groundwater geophysical characteristics. The specific research work and contributions are listed from four aspects as follows:1) Because interferometric phase noise seriously affects the InSAR monitoring accuracy, Compare much variety filtering methods, two dual-tree complex wavelet filtering method was proposed, which is conducted in using SAR simulation data and real interferogram data. Comparing with the precision with other methods, two dual-tree complex wavelet filtering method can greatly improve the filtering precision.2) Because of atmospheric delay in InSAR interferogram, InSAR altimetry and deformation precision are affected. On this basis, combined with the InSAR image on the atmospheric delay characteristics, existing methods of atmospheric interpolation model were studied. Von_Kriging spatial interpolation method Based on the terrain model is put forward in MERIS data. After search for the optimal parameters, ordinary Kriging method and Von_Kriging method interpolation are compared at accuracy. Interferogram with the same time of MERIS data is used to study. The result shows Cangzhou region affected by atmospheric effects obviously, which must be removed for precise survey.3) Based on the SBAS technology and IPTA technology characteristics, a new algorithm is put forward. Cangzhou city surface deformation was extracted by the algorithm, which include of the effective separation of linear and nonlinear deformation. Atmospheric delay and noise are obtained by spatio-temporal filtering method. Finally, the deformation results is contrasted the groundwater with abundant water period and low water period.4) Subsidence result is extracted by improved SBAS technology in Cangzhou city with different periods. The change of underground water level data combined with subsidence results was used to estimate the regional aquifer elastic storativity and non-elastic storativity in different monitoring wells in the study area. The experimental results revealed that the area in some places has already occurred more severe plastic deformation, which need to effectively control the exploitation quantity of groundwater. Finally the underground water level subsidence and subsidence were analyzed to find stratum subsidence mechanism.