Combining SAR interferometric phase and intensity information for monitoring of large gradient deformation in coal mining area

Coal mining usually causes drastic large gradient deformation in the earth's surface in a short period, which leads to the formation of collapse basin or collapse pit. The drastic deformation renders the generation of dense fringes in interferogram, leading to difficulties in the phase unwrapping step. In this paper we propose using intensity tracking technique to monitor large gradient deformation in the subsidence center. To obtain the small deformation information around the basin and collapse pit, we use Small Baseline Subset (SBAS) interferometry technique to monitor the small deformation, after which we integrate the results under the two methods to obtain complete monitoring results. We take Daliu Tower mining of Shanxi Province in China as an example, using TerraSAR-X satellite data of 13 scenes spanning from 21/11/2012 to 02/04/2013 to conduct deformation monitoring experiment. The experiment result shows that the proposed method has the capability to detect and measure the large gradient deformation, meanwhile, small deformation information is preserved. Moreover, by comparing the experiment monitoring results to continuous GPS measurements, we estimate that the accuracy of deformation monitor is about 8 cm in the range direction.