Application Research Of Multi-rotor UAV Aeromagnetic System

The Ma’anshan iron ore deposit in Jinping County,Yunnan Province,located at the southern end of the Mourning Mountains on the Yunnan-Guizhou Plateau,is facing a resource crisis with years of continuous mining,and there is an urgent need to find deep replaceable resources.The main mineral in the deposit is vanadium-titanium magnetite,and the magnetic parameters of the ore-bearing rocks are significantly different from those of the surrounding rocks,therefore,magnetic exploration is chosen as the main survey technique to effectively probe the distribution of the ore-bearing rocks,so as to achieve the purpose of finding ore.The complex alpine geomorphology makes it difficult to carry out the ground survey work,therefore,this paper takes the aerial magnetic survey system composed of a multi-rotor UAV with a proton magnetometer as the main object of research,and carries out the prospecting exploration work at the periphery of the deposit(within the area of the prospecting right).Based on the summary of the multi-rotor UAV aeromagnetic system,the distribution pattern of the magnetite-bearing basal-ultra-basic heterogeneous rocks is inferred,and then the target area is circled and verified by drilling.The following observations and conclusions were made in this paper:1、In the mining area of Maanshan iron ore deposit in Jinping,Yunnan,the basal-ultramafic heterogeneous rock body is the ore-bearing rock body,and its magnetic parameters are significantly different from the surrounding rock,which can provide the necessary physical prerequisites for magnetic exploration.2、This paper ensures the reliability of the UAV aerial magnetic system through flight test,host consistency test,instrument noise level test,GPS positioning accuracy determination and aerial magnetic data quality evaluation and other evaluation methods.3、For the problem that the day-varying data contains noise in the aerial magnetic work,this paper adopts empirical mode decomposition(EMD)for noise suppression,and in the simulation experiment,the signal-to-noise ratio is improved from 21.69 to 31.81,and the root mean square error is reduced from0.57 to 0.18,which verifies the effectiveness of the noise reduction method.4、For the aeromagnetic measurement data,this paper proposes a new preprocessing method,which suppresses the local negative anomalies with large values and the local prominent anomalies consistent with the course direction by calculating the normal distribution law of the magnetic field values,and supplements the blank field strength values by the inverse distance weighting method to make the positive and negative anomaly distribution of ΔT clearer and retain the regional distribution characteristics of the geomagnetic field.5、This paper uses multiple processing tools to analyze regional magnetic field characteristics,integrates other geological data for mineralization prediction,circles three anomalous zones,and implements drill holes ZKS0-1,ZKS15-1,ZKS15-2,ZKS20-1,and ZKS27-1 to verify the TB1 anomalous zone,all of which expose magnetite bodies tens of meters thick and achieve good ore finding results.