Study Of Key Techniques Of PS InSAR And Its Applications To Monitor Mining Land Subsidence

Although there are many successful examples of applying PS InSAR or D-InSAR technique to monitor land subsidence, its application have not yet entered the running of business because of the limitation of SAR data and some key techniques, such as the coregistration of low-coherent SAR image pairs, the identification and selection of PS pixels,' the models and methods of estimating deformations precisely, etc. Finaced by the national high technology research and development program of China (2009AA12Z147-B sub-topics) and national natural science foundation of China (No.40874001) and other related projects, this paper systematically investigates some key techiques of PS InSAR and application of D-InSAR and PS InSAR to monitor the land subsidence of mining areas. The main reseach contents include the following aspects:(1) As the theory foundation, this paper investigates the basic principles and work patterns of satellite SAR, InSAR, D-InSAR and PS InSAR, summarizes the pratical data processing flows and methods, and finally analyzes and.discusses their key techniques and algorithms in detail.(2) This paper systematically investigates the key techniques related to differential interferogram generation in PS InSAR as follows:(Ⅰ) Analyzes and investigates the principles and practical data-processing processes to optimaze and select common "master" images from a series of SAR images based on the DESCW and the integrated correlation coefficientγm Presents and implements a new method to optimize and select a common "master" image or more based on the DESCW and minimum sum of three baselines considering the impact of spacial perpendicular baselines, temperal baselines and doppler centers frequency baselines on the decorrelation of interfero grams. Finally compares and analyzes two methods through a test. (Ⅱ) Investigates the basic steps and existing available methods of the coregistration of SAR image pairs detailedly and deeply. Presents and implements a new coregistration method of PS InSAR based on weighted least squares for the coregistration of low-oherence SAR image pairs, gives the principle, basic data processing steps and algorithm of the new coregistration method and carries out a test to verify its effectiveness. (Ⅲ) Researches and analyzes two ways of obtaining external DEM and the process of differential interferogram generation in PS InSAR technique.(3) This paper investigates the identification and selection of permanent scatterers of PS InSAR comprehensively and systematically, it mainly includes:(Ⅰ) Discusses and analyzes systematically the basic principles of the existing available methods and summaries their pratical data processing procedures and methods to identify and select permanent scatterers. (Ⅱ) Introduces the wavelet filtering theory into permanent scatterers identification and selection and presents the identifying and selecting permanent scatterer pixels new method based on wavelet phase analysis, and verifies its feasibility from theoretical and experimental study with specific SAR images data.(4) This paper investigates the deformation estimation models and algorithms of PS InSAR deeply. It compares and analyzes the existing available deformation estimation models and resolving methods of PS InSAR detecting surface deformation, summarizes the practical data processing flow of existing PS InSAR techniques monitoring land subsidence, systematically sums up the PS InSAR technique based on differential phase analysis of PS pairs and a variety of filtering methods to detect land subsidence in the theory and practical data processing, finally carries out a deformation estimation test using special SAR images with the help of StamPS.(5) Taking land subsidence of in Jibei coal mining areas as the research objects, this paper carries out the tests of D-InSAR and PS InSAR monitoring the land subsidence of mining areas with the specific SAR data.