Research On Data Acquisition System Of Aeromagnetic Three-component Based On Rotor UAV

The aeromagnetic measurement technology has experienced three stages: the total field measurement,the total field gradient measurement and the current vector(three component)measurement.Compared with the total field and the total field gradient measurement technology,the three-component measurement can solve the problem of low vertical resolution in the processing of magnetic data,and effectively reduce the multi-solution in the interpretation of magnetic anomalies,which has become the research focus of the current aeromagnetic survey technology.UAVs are characterized by miniaturization,flexible flight and low operating cost.Using UAVs as a platform and carrying three-component equipment to carry out high-precision magnetic survey in small and medium-sized test areas,it is easier to reflect the magnetic anomaly characteristics in local test areas,which has important application value.Based on the analysis of the research status of aeromagnetic three-component at home and abroad,and according to the requirements of the carrier flight environment,this paper designs a set of aeromagnetic three-component data acquisition and collection system suitable for rotorcraft UAV.Specific research contents are as follows:(1)Designed high-performance power module for different voltage levels of sensors and chips.In view of the noise introduced by the triaxial fluxgate sensor in the signal transmission process,the signal conditioning circuit is designed,and the static error of single channel is better than 20 n V /?Hz@10Hz.Based on the advantages of FPGA parallel processing,the ADC chip driver design is realized,and the timing constraints and simulation are completed.The timing design of hardware synchronization based on PPS second pulse is completed,and the synchronization error is better than 400 ns.(2)Based on the advantage of high-speed serial algorithm of ARM platform,the design of digital filtering module is realized through wavelet threshold method,and the design of SD card inclusion module is realized through FATFS control structure.LabVIEW upper computer software is developed based on PC operating platform,which is used for noise evaluation,error calibration and system verification.The wireless data monitoring software is designed based on the i Pad operating platform,which is used for UAV control,system parameter deployment before take-off,flight test area and test line planning and flight scheme selection.(3)Calibration and correction experiments,ground mobile measurement experiments and field flight experiments were carried out.The non-linearity error of the acquisition system is better than 5.5n T,and the static noise level is better than 1n T.A mobile magnetic survey experiment was carried out on the ground,and a magnetic target 3m away from the survey line was successfully detected.The total field of the three-component synthesis is consistent with the results measured by the optical pump magnetometer.The experimental results show that the aeromagnetic three-component data acquisition and collection system developed in this paper is stable and reliable,and can meet the actual exploration needs.