Key Algorithms On Mining Subsidence Monitoring Using InSAR

InSAR is a microwave remote sensing technique that enables the measurement of surface deformation with a centimeter to millimeter accuracy and with a large spatial coverage capability.InSAR has a huge advantage than traditional monitoring methods in the mining subsidence monitoring.This paper describes the basic principles of InSAR technology and analyzes the present situation and existing problems of InSAR technology for mining subsidence monitoring; then the key problems such as decorrelation caused by high phase gradient factor and nonuniform subsidence in mining subsidence monitoring are summarized and analyzed. The study focus on oversampling method used to improve coherence of SAR images and the quality of the interferogram by the example of mining area in Tangshan city. It makes the interference fringe of subsiding area clearer and the boundary more obvious.By using this method to process InSAR data, we obtain 66 pairs of interferogram of Tangshan mining area.In addition, we derived the nonuniform time series of mining subsidence using linear fitting method and the spatial correlation method. The surface subsidence and temporal evolution of several particular monitored points located in center of mining areas are analyzed in detail and found that Tangshan mining area subsided closed to 90 mm from November 2004 to January 2005.The result provides the data support for guiding the buildings, railways and other infrastructure construction and distribution in the mining area and verifies the feasibility of InSAR technology in the mining city of surface subsidence monitoring, to meet the needs of sustainable development of coal mining area.