Study On Information Extraction Methods Of SAR In Mining Subsidence Monitoring With Large Gradient

At present, the coal consumption is still the largest part of the energy consumption, more than 65%. The surface subsidence and ecological environment problems caused by exploitation of coal resources, becomes a focus of attention at home and abroad. Mining subsidence monitoring is the foundation for the research of the law of mining subsidence. Thus, how to fast and effective monitor the mining subsidence is generally the focus for researchers. There are many disadvantages for the traditional technique in mining subsidence monitoring, and it's difficult to satisfy the need of the development of the productivity. Synthetic aperture radar interferometry(In SAR) technology developed in recent years has been a new method for the mining subsidence monitoring owing to its measurement advantages of the large area, all-weather, high precision. Therefore, the In SAR technology was used to monitor mining subsidence in our thesis, and the algorithms to monitor t the subsidence in the areas of large gradient of mining subsidence were investigated. The main work and achievements are listed as follows:(1) To verify the capacity of the In SAR technology in monitoring mining subsidence with small gradient, D-In SAR and SBAS technique were applied to monitor mining subsidence in Shandong, respectively. The results were further compared and analyzed between the two kinds of In SAR technology in mining subsidence monitoring application.(2) The In SAR technique can only monitor mining area with small gradient of mining subsidence. Based on the in-situ measurements and relevant theories of mining subsidence, the integration method of time-series In SAR technique and probability integral method for surface subsidence information extraction was developed. The SBAS method is used to extract the subsidence basin edge information, in combination with the GPS measurements for the parameter inversion of probability integral method, the SBAS measurements and the prediction results of the probability integral method were comprehensively analyzed. The results were further discussed based on the GPS measurements.(3) In the area with large gradient of mining subsidence, it is difficult to monitor the subsidence using the In SAR technique without monitoring stations on the ground.Therefore, a method is developed which combine the D-In SAR and Offset_tracking technology in the large gradient of mining subsidence. The experiment firstly discussed the influence of the window size and the oversampling factor of Offset_tracking algorithm, then D-In SAR and Offset_tracking technology were used to extract subsidence basin edge and center of subsidence information, respectively. The time-series deformation figure above the working face can be obtained by the combination of the D-In SAR and Offsed tracking results. Finally the precision of the method was analyzed based on the GPS measurements.(4) Considering the error model of the Offset_tracking algorithm, the system offset model which include the errors of orbit and terrain was established to improve the monitoring accuracy of the Offset tracking technique. The monitoring precision of the improved Offset_tracking technology is discussed.