Performance of Two Different Flight Configurations for Drone-Borne Magnetic Data.

Filippo Accomando,Maurizio Buonanno,Giovanni Florio,Andrea Vitale,Antonello Bonfante

doi:10.3390/s21175736

Abstract

The compensation of magnetic and electromagnetic interference generated by drones is one of the main problems related to drone-borne magnetometry. The simplest solution is to suspend the magnetometer at a certain distance from the drone. However, this choice may compromise the flight stability or introduce periodic data variations generated by the oscillations of the magnetometer. We studied this problem by conducting two drone-borne magnetic surveys using a prototype system based on a cesium-vapor magnetometer with a 1000 Hz sampling frequency. First, the magnetometer was fixed to the drone landing-sled (at 0.5 m from the rotors), and then it was suspended 3 m below the drone. These two configurations illustrate endmembers of the possible solutions, favoring the stability of the system during flight or the minimization of the mobile platform noise. Drone-generated noise was filtered according to a CWT analysis, and both the spectral characteristics and the modelled source parameters resulted analogously to that of a ground magnetic dataset in the same area, which were here taken as a control dataset. This study demonstrates that careful processing can return high quality drone-borne data using both flight configurations. The optimal flight solution can be chosen depending on the survey target and flight conditions.

Highlights

Magnetic survey represents a rapid, non-invasive, and cheap prospection strategy, which makes it widely used in applied geophysics
The two configurations illustrate the possible solutions to obtain, on the one hand, the stability of the unmanned aerial vehicles (UAVs)-magnetometer system during flight and, on the other hand, the minimization of the magnetic and electromagnetic noise generated by the mobile platform
It is clear that the need to stabilize the magnetometer during flight and to minimize the UAV-related noise solicit the implementation of contrasting strategies, so that the solutions tested in this study can be considered as end-members of possible flight configurations for a magnetometerUAV system

Summary

Introduction

Magnetic survey represents a rapid, non-invasive, and cheap prospection strategy, which makes it widely used in applied geophysics. The most common applications concern targets of geological, archaeological, and engineering interest. In recent years, unmanned aerial vehicles (UAVs), or drones, have become standard tools for acquiring spatial data to support various geoscientific analyses, reducing the cost and the time necessary to complete a survey, allowing extension of the prospections even over places of difficult access, and limiting the risks for field personnel. Several geophysical instruments have been mounted on UAVs as payloads (hyperspectral cameras, magnetometers, radar antennas, gamma-ray detectors), opening up the possibility of doing “drone geophysics”. The integration of UAV and magnetometers is opening new perspectives to the search and modelling of shallow magnetized sources. The possible fields of applications include topics of primary interest today, such as the field of mining exploration, the identification of active faults, or other geological targets. Drone magnetometry has its role in engineering applications, such as archaeogeophysics and the preliminary studies to the decommissioning of oil industry infrastructures

Results

Discussion

Conclusion