Key technology and application of InSAR /UAV fusion monitoring for coal mining damages

Geological environment damage caused by coal mining has become the focus of attention. The western mining area is dominated by large-scale and high-intensity mining, and the rock strata and surface movement caused by mining also show the characteristics of fast deformation speed, deep damage degree and wide spread range. Rapid, accurate and comprehensive monitoring is the key to ecological environment protection and green mine con-struction in mining areas. The traditional monitoring technology of surface movement damage and single measurement technology are difficult to meet the demand. UAV photogrammetry and InSAR have comple-mentary advantages, and their integration has advantages in monitoring geological environment damage. This paper puts forward the key theories and technologies of fusing UAV/InSAR to monitor mining damage, and focuses on the establishment mode of UAV/InSAR fusion new multi-scale observation station and the cooper-ative observation method. The fusion strategy of UAV/InSAR cross-scale heterogeneous remote sensing data is discussed. The idea and method of accurate extraction of surface subsidence deformation and key environmental factors based on UAV/InSAR feature level fusion are put forward. Taking Wangjiata Coal Mine in Inner Mon-golia as an example, the application research is carried out. A new model observation station in working face scale is established using UAV photogrammetry and InSAR technology to combine “point-line-surface”, and UAV optical images, InSAR images and key point leveling data of the main section in the study area are obtained. The UAV/InSAR feature-level fusion method is used to extract the subsidence basin in mining area, and the parameters of UAV subsidence basin and fusion subsidence basin are calculated respectively. The research results show that the maximum subsidence value monitored by UAV is 2 487 mm and the median error is 81 mm. The UAV measurement error has a greater in-fluence on the boundary of subsidence basin, which leads to the inability to accurately obtain the basin boundary area of basin. The maximum subsidence monitored by InSAR is 110 mm, which is far less than the actual situ-ation. InSAR is affected by spatio-temporal decoherence and cannot accurately obtain the subsidence in large deformation areas. Through InSAR/UAV feature-level fusion, the overall accuracy and boundary area of the fused sinking basin are higher. In terms of parameters calculation, the relative error between the subsidence coefficient calculated by UAV data alone and the leveling result is 1.4%, and the main influence tangent deviation is relatively large, about 20%, which is mainly caused by the large error of the UAV subsidence basin boundary. Compared with UAV alone, the parameters obtained by fusing the subsidence basin data are more accurate, and the relative error of the mainly affecting tangent is only 5%. The fused data well solves the problem of large tan β error. This engineering case shows that UAV/InSAR fusion technology has obvious ad-vantages in surface subsidence deformation monitoring in western mining areas. The research results provide technical support for surface damage monitoring in coal mining in western coal mining in China.