Research On Monitoring Method Of Mining Subsidence For UAV Tilt Photogrammetry

Due to the subsidence and deformation of ground surface caused by underground mining activities,the means of subsidence monitoring have undergone a long change process,from traditional leveling traverse survey,GPS monitoring to many methods such as three dimensional laser scanning monitoring and D-InSAR monitoring.These monitoring methods are from the whole field to the partial field mode,the observation efficiency is also greatly improved,but its monitoring range,accuracy and efficiency still can not meet the needs of comprehensive monitoring of mining subsidence.At the present,the emergence of low altitude photogrammetry has greatly improved the efficiency of monitoring with its high maneuverability and real-time performance.Its high-precision digital results are applied to various monitoring fields,including monitoring landslides,debris flows and collapses in mountain areas,and monitoring subsidence area in a full range of perspectives.In view of the surface subsidence caused by mining in mining area,this paper combines the progress of underground mining and the monitoring of unmanned aerial vehicle surface subsidence,based on the measured observation data,and discusses the feasibility of unmanned aerial vehicle mining subsidence monitoring,Discussed separately from the following aspects:(1)First,the vertical photography and oblique photography of the UAV photogrammetry are compared and analyzed.The advantages of oblique photography are explained and discussed separately from the image distortion correction of the vertical photogrammetry,the image Pyramid establishment,the relative orientation and the free network adjustment,and the matching of the same name points with the tilt photogrammetry,the joint adjustment of the multi camera,the point cloud generation,the texture mapping and the surface reconstruction.(2)Before entering the subsidence area,the design of UAV aerial survey is designed.The first part is the design of the layout scheme of the image control point.Combining two classical sparse and dense layout schemes,the precision of the digital results of the UAV under these two schemes is verified,so as to get a set of reasonable image control point scheme.The second part is the reference and proof of the post differential technology,and compares the digital results with the post difference technology of two sets of data,and verifies the accuracy and advantages of the post differential technology.The DEM accuracy of tilt and vertical photography is compared under the same scheme,and the best oblique aerial photography scheme is obtained.(3)The oblique aerial photography scheme is introduced into the subsidence area,and two phases of the ground unmanned aerial vehicle(UAV)tilt data corresponding to the underground mining activities are obtained,and the data of two stages of ground observation stations are measured by the leveling instrument.Two phases of the unmanned aerial vehicle(UAV)data are processed to form two phases of DEM and the subsidence basin is generated,using the empirical parameters of the mine to make subsidence basins expected to form prediction subsidence basins;The subsidence basin obtained by the tilt photography is quantitatively analyzed by the measured observation line data,and the subsidence basin obtained by the prediction subsidence basin is qualitatively analyzed.The above research and verification show that compared the subsidence area monitoring by oblique photogrammetry and the measured ground subsidence value of the leveling wire,it is found that the subsidence basin is basically in agreement with the ground measured subsidence value at the key point and the middle error can reach 102mm;Compared the subsidence basin by predicted,it is found that the subsidence basin by oblique photogrammetry is consistent with that of mining area in the trend of subsidence.