Research On UAV Monitoring Method And Application Of Surface Deformation In Mining Area

As one of the main energy sources for Chinese economic development,coal mining will affect the ecological environment,and the subsidence of the surface basins caused by underground mining is one of the important manifestations of the destruction of the ecological environment.Monitoring the development process of surface subsidence basins is an important means to provide basic data for underground mining planning,surface ecological protection,and land resource reclamation.Traditional monitoring methods can only obtain the elevations of a few points on the main section of the subsidence basin,and the impact range the elevations of other points are difficult to obtain,and horizontal movement is also the key monitoring object for surface deformation.However,there is still no good method for automatic monitoring of horizontal movement.In order to solve the above problems,this article proposes a set of photography using drones.The measurement technology can simultaneously monitor the amount of subsidence and the method of horizontal movement within the scope of mining subsidence,and the important factors affecting the monitoring accuracy have been studied through internal experiments.On this basis,a better field engineering practice plan has been proposed.The project conducted a one-month deformation monitoring on the 33 upper 08 working face of Nantun Coal Mine in Shandong Zoucheng and obtained results that were in line with expectations.This article mainly carried out the following research work and achieved related research results:(1)According to the reconstruction process of the SFM algorithm,the error generation principle of the photogrammetry technology is analyzed,and the influence of the image outer orientation element on the sparse point cloud reconstruction error is deduced through the simplified dual-view model.The impact of the included elevation error and plane error is different,and the elevation error must be greater than the plane error.As the flight altitude increases,the growth rate of the elevation error is greater than the growth rate of the plane error,which is caused by the principle of the technology;(2)The existing UAV photogrammetric sinking extraction method is improved,and the reconstructed digital surface model is refined through road point cloud filtering experiments.The experiment shows that the altitude will not only affect the system error in the reconstruction error,it will also have an impact on accidental errors,and as the altitude increases,its impact on the two will be greater.The results show that the point cloud can be filtered by a voxel filter to obtain a higher accuracy result,but It can only eliminate accidental errors of the data,and the elimination of systematic errors can only be eliminated by the difference between the two periods of data.The improved method was used to carry out a sink extraction experiment on a certain area in the school,and the results showed that the error of the method is reasonable and reliable results can be obtained;(3)A method for extracting horizontal movement from the digital orthophoto model generated by UAV photogrammetry technology is proposed,and the key steps and techniques of the method are introduced.Using this technology to carry out horizontal movement extraction experiments in a certain area of the school,the results show that this method can effectively monitor the horizontal movement in the area(except for areas without obvious characteristics such as water areas),and the errors are all within a reasonable range;(4)Using a computer to simulate the phase control point coordinates that meet the accuracy requirements to study its influence on the accuracy of sinking and horizontal movement extraction;also by obtaining UAV images of different altitudes,the effects of altitude and image migration on the above the influence of deformation extraction accuracy.The results show that as the error of the image control point increases,the error of the deformation extraction increases,but its influence on the extraction accuracy of the horizontal movement is greater than that of the sink extraction accuracy.When the error of the phase control point is E_XY=E_H=6cm,the extraction accuracy of the two is almost the same at about 6.5cm,and then the horizontal movement extraction error is greater than the elevation extraction error;there is a linear relationship between the increase of the altitude and the extraction accuracy of the horizontal movement,but the accuracy of the sinking extraction(within 100m of height),the impact is not large,basically about 1cm;the image offset is corrected by manual point selection and SIFT extraction of feature points.The results show that image registration can effectively improve the accuracy of deformation extraction,especially effective for horizontal movement;(5)The error distribution law of UAV photogrammetry was studied.By collecting50 sets of image data under the same aerial survey conditions and performing three-dimensional reconstruction on them,the error between the actual measurement results and the reconstruction results was analyzed.Elevation error contains both accidental errors and systematic errors,and multiple observations can effectively reduce reconstruction errors,especially elevation errors,3 observations can reduce 63%;(6)The mining subsidence prediction,leveling measurement and UAV photogrammetry were carried out on the 33 upper 08 working face of Nantun Coal Mine in Zoucheng,Shandong.The actual measurement results were compared with the predicted results.The results showed that the UAV subsidence monitoring accuracy is1cm and the horizontal movement monitoring accuracy is 2cm,which can describe the surface changes well.The paper has 122 pictures,29 tables,and 53 references.