| China is a coal producer and consumer country,a large number of coal resources to make an important contribution to the economic construction,at the same time also bring a series of environmental and geological disasters.It is very important to strengthen the monitoring of the surface deformation caused by the exploitation of coal resources in the mining area for the ecological environment restoration and disaster prevention and management of the mining area.The emergence of InSAR technology provides a new method for mine deformation monitoring.However,due to the limitation of deformation gradient of surface subsidence basin,InSAR technique based on phase unwrapping is difficult to obtain large-gradient deformation of surface in high-intensity mining,which can only be effectively monitored for small-gradient deformation of the subsidence basin.The Pixel-tracking method based on SAR image intensity information provides a new technical means for monitoring large-scale and large-scale deformation of mining area.This paper focuses on the fine monitoring of large gradient and large-scale surface deformation based on SAR image.The main contents and achievements are summarized as follows:(1)This paper summarizes the research status of the existing InSAR technology to monitor the deformation of the mining area,expounds the basic principles of the D-InSAR,InSAR and Pixel-tracking methods,simulates the surface subsidence according to the probability integral method,analyzes the different wavelengths,different pixel sizes TerraSAR-X images,Radarsat-2 images and ALOS-PALSAR images monitor the applicability of mine deformation.(2)A locally adaptive template sizes of the Pixel-tracking method is proposed.Using the probability integral method to predict the surface deformation caused by different geological mining conditions under different geological mining conditions,the simulated deformation is added to the SAR image intensity information of three different pixel sizes.The influence of cross-correlation window size,pixel size and interdigital interpolation factor on the accuracy of Pixel-tracking method is studied.It is found that the small cross-correlation template can cause the pixel mismatch seriously,too large cross-correlation template will cause "deformation compression" phenomenon in the subsidence basin.The analysis of the causes of the "deformation compression" phenomenon in the subsidence basin caused by the large cross correlation window is carried out,and the SNR is redefined.According to the deformation characteristics of the mine,the peak matching position of the cross correlation coefficient is constrained,which greatly reduces the frequency of pixel mismatch.Based on the redefined SNR,the SNR maximum value is found by transforming the template step in a certain interval.The maximum cross-correlation template is the optimal cross-correlation template,and the deformations in mining area are monitored based on the optimal cross-correlation template.By using the Radarsat-2 image covering the 52304 working face in Daliuta Mining area,it is proved that this method can improve the monitoring accuracy obviously with respect to the Pixel-tracking method of the fixed cross-correlation calculation template.(3)A Pixel-tracking method which takes into account the terrain correction is proposed,which reduces the influence of terrain factors on the accuracy of Pixel-tracking.The method of time series SAR image intensity and standard deviation double threshold constraint are used to screen the points where the image intensity are stable in SAR image.According to the principle of uniform distribution and avoiding t the impact of mined-out,the primary stability points are refined.According to the subsidence information of the stable points,the least square polynomial surface fitting method is used to weaken the orbital error,atmospheric error and partial terrain error in the Pixel-tracking method.According to the residual of the stable points,the external DEM data is introduced,the quadratic polynomial fitting is carried out based on the elevation information,and the influence of the terrain on the accuracy of the Pixel-tracking method is reduced.The GPS data in 52304 working are used to verify the accuracy.(4)Based on the idea of SBAS-InSAR,in order to observe the results of Pixel-tracking method both certain time and space baseline constraints are used,the deformation of each observation period is obtained by using the deformation of the observation period instead of the average deformation rate.Combined with the mining speed,the results of the SBAS-Pixel-tracking method are analyzed and the monitoring accuracy of this method was evaluated by the GPS data of the surface observation station.(5)The solution of multi-platform to obtain three-dimensional deformation is optimized,according to two platform SAR data,the three-dimensional deformation in mining area can be obtained.According to the ability of monitoring deformation in range direction and azimuth direction by Pixel-tracking,3-Dimensional deformation field of 52304 working face were obtained.Based on the measured data of the surface mobile observation station,the accuracy of the three-dimensional deformation field acquisition based on the Pixel-tracking method is evaluated.(6)A fusion method based on priori deterministic of time-series InSAR and Pixel-tracking is proposed.Four time series InSAR methods are used to monitor the small-gradient deformation of the edge of the subsurface basin in the 52304 working face.Based on the GPS data of the surface movement observation station,the accuracy of the small-gradient deformation monitoring of the four time-series InSAR methods in mining area is evaluated respectively,and the high accuracy monitoring results in small-gradient are obtained.The large-gradient and large-scale deformation of the 52304 working face is monitored by SBAS-Pixel-tracking method.Based on the priori variances of the time-series InSAR and SBAS-Pixel-tracking,the results of the time-series InSAR and SBAS-Pixel-tracking are fused.According to the fusion results,some parameters of mining subsidence are obtained. |
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