Research On Slope Deformation Monitoring Of Open-pit Mine Based On BDS/GPS Combined System

Open-pit mining is a common type of mining,but because of its special operation and construction methods,it is easy to cause a series of environmental problems such as geological disasters,vegetation desertification,air pollution,water pollution and biodiversity destruction.In response to the environmental problems in the open-pit mining area,the open-pit mine slope was monitored for deformation.Maintaining the stability of the slope and preventing secondary pollution damage to the environment caused by landslides are important tasks for environmental governance in mining areas.Satellite positioning technology is widely used in deformation monitoring due to its short monitoring period and high positioning accuracy.With the completion of the Beidou-3 Global Satellite Navigation System(BDS-3),the combined mode of Beidou Satellite Navigation System(BDS)and Global Positioning System(GPS)implements high-precision deformation monitoring on open-pit slopes,which is an effective means to improve the accuracy of slope monitoring and realize environmental early warning.Starting from the actual situation of the open-pit mine slope,this article analyzes the positioning performance of GPS,BDS-3 single system and BDS-3/GPS dual system in view of the adverse monitoring conditions of the slope with serious obstruction.Determine the correlation model between the station and the positioning accuracy under different occlusion directions to improve the accuracy of slope monitoring.The receiver is set up to simulate the mining field measurement environment under the environment of shielding in different directions on campus,and static data acquisition is carried out.The difference method is used for data processing.The positioning accuracy of each station is compared and analyzed,so as to verify the applicability of the correlation model in high-precision differential positioning.BDS-3/GPS combined positioning method is applied to slope monitoring,and according to the correlation model,monitoring stations are selected in the open-pit slope for deformation monitoring,to judge whether there is landslide risk.According to this research idea,the main research contents of this paper are as follows:(1)Through the data of Multi-GNSS Experiment(MGEX)station,simulate a variety of occlusion environments,and use GPS,BDS-3,BDS-3/GPS three modes for pseudo-range single-point positioning analysis.Due to the small number of visible satellites and poor satellite spatial geometry,the positioning performance of a single system is reduced in an obstructed environment,while the dual system greatly increases the number of satellites involved in positioning and provides more redundant observations.The dual system ensures the epoch utilization and improves the positioning performance.(2)Comparative analysis of the positioning performance under different azimuth occlusion and different height occlusion.The positioning accuracy decreases with the increase of the occlusion height angle,and the positioning accuracy of the occlusion in different azimuths varies with the latitude.In the low latitudes of the northern hemisphere,the positioning performance of occlusion in all directions is not much different.However,with the increase of latitude,the advantages of occlusion positioning accuracy in the north compared to the south in the mid-latitude area gradually appear,especially in the case of the BDS-3 single system.(3)Simulate the actual measurement environment of the mining area,and conduct static data collection under the two opposite dormitories in the north and south of the campus.Pseudorange difference and carrier phase difference are performed on the two stations and the reference station respectively.The result verifies the improved positioning performance of the combined system relative to the single system in the occlusion environment,and the positioning accuracy of the north occlusion in the mid-latitude area is significantly better than that of the south.(4)Based on the above conclusions,a monitoring station was set up on the northern slope of the open-pit mine for deformation monitoring.Collected 24 hours a day data and used the double-difference model to calculate the baseline of the data.The positioning accuracy meets the requirements of slope monitoring in the mining area.The displacement of the slope is lower than the safety warning value.There is no risk of landslides.