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With the rapid development of unmanned aerial vehicles (UAVs) technology, using UAVs for magnetic surveys is a booming branch. However, the magnetic interference generated by the UAV hinders the further application of UAV magnetic survey systems. In addition to the interference caused by the UAV maneuvering, the dynamic interference of airborne equipment has also been found and become one of the factors restricted by the detection accuracy of magnetic surveys. This paper proposes a multi-source two-channel linear time-invariant (MTLI) correlation model, considering the maneuvering magnetic interference and airborne equipment magnetic interference. The magnetic interference can be estimated and compensated by interference correlation without current sensors. Compared with the traditional aeromagnetic compensation process and other compensation methods considering the magnetic interference of airborne equipment, the proposed method can provide stable compensation effects in maneuvers and smooth flight, and the workflow is simple and fast. The actual flight experiment is conducted, and the results show that the two kinds of UAV interference fields are suppressed significantly with a root mean square error of 0.0062 and 0.0296 nT in smooth flight and maneuvering flight. [ABSTRACT FROM AUTHOR]

An overview of applications of geomagnetic data for practical purposes is presented. Many of them involve models of the Earth's main magnetic field and spatial distribution of anomalous magnetization of the upper lithosphere as input parameters. Unmanned aerial vehicles (UAVs) can significantly improve the efficiency of detecting magnetic anomalies. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicles (UAVs) have become an important part of modern fieldwork. Constant innovations, expansion of the functionality of UAVs, and the reduction of their costs are creating new opportunities for drones to be used in geophysical research. The conditions prevalent in difficult terrain are no longer insurmountable. UAVs allow magnetic surveys to be carried out faster than portable magnetometers carried on foot and they also use much fewer resources than manned aviation. There is a need for UAVs designed to perform such tasks. The prototype created includes the equipment needed for programming and operating the vehicle for conducting geophysical research and storing the data obtained. It is tested under different conditions in order to define the optimal technical parameters of the UAV. Detailed technical descriptions of the prototype, the different stages of the experiment conducted, and operation procedures for controlling the prototype are described. [ABSTRACT FROM AUTHOR]

In the past two decades, unmanned aerial vehicles (UAVs) have been used in many scientific research fields for various applications. In particular, the use of UAVs for magnetic surveys has become a hot spot and is expected to be actively applied in the future. A considerable amount of literature has been published on the use of UAVs for magnetic surveys, however, how to choose the platform and reduce the interference of UAV to the collected data have not been discussed systematically. There are two primary aims of this study: (1) To ascertain the basis of UAV platform selection and (2) to investigate the characteristics and suppression methods of UAV magnetic interference. Systematic reviews were performed to summarize the results of 70 academic studies (from 2005 to 2021) and outline the research tendencies for applying UAVs in magnetic surveys. This study found that multi-rotor UAVs have become the most widely used type of UAVs in recent years because of their advantages such as easiness to operate, low cost, and the ability of flying at a very low altitude, despite their late appearance. With the improvement of the payload capacity of UAVs, to use multiple magnetometers becomes popular since it can provide more abundant information. In addition, this study also found that the most commonly used method to reduce the effects of the UAV’s magnetic interference is to increase the distance between the sensors and the UAV, although this method will bring about other problems, e.g., the directional and positional errors of sensors caused by erratic movements, the increased risk of impact to the magnetometers. The pros and cons of different types of UAV, magnetic interference characteristics and suppression methods based on traditional aeromagnetic compensation and other methods are discussed in detail. This study contributes to the classification of current UAV applications as well as the data processing methods in magnetic surveys.

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.

The relevance of the discussed issue is caused by the need to study the natural physical fields and their relations with the geological environment. The main aim of the work is to study the magnetic field and the nature of its changes on the typical Siberian sulfide quartz vein gold deposits Darasun. The methods used in the study: specialized experimental methodological field magnetic survey of various observational accuracy and detail of network measurement, laboratory determination of magnetic susceptibility of purposefully selected samples of rocks and ores, statistical analysis of the data, comparing them to known elements of the geological structure of ore-bearing area and its surroundings. The results. The authors have obtained the areal pattern of changes of magnetic induction increment within the ore field of Darasun deposit and its near neighborhood, determined the spectral composition of its changes, magnetic field and relationships with various elements of the geological structure of ore-bearing area Darasun, revealed physical and geological nature of various anomalous zones and provided a basis for assessing the possibilities of magnetic prospecting in solving various geological problems in the stages of prospecting and exploration of quartz-sulphide vein gold deposits in Siberia.

In the Taverna San Felice limestone active quarry (Italy) excavation has progressively exposed a magmatic dike embedded in a calcareous succession. The dike outcrops are scattered among the high vertical steps of the quarry, whereas outside the excavated area the steep mountain slope covered by a dense bush vegetation make direct inspection and geological mapping a challenging task. To map the areal extension of the dike and to define its direction and its relationship with tectonic lines over an area larger than the quarry, a magnetic survey was performed. Given the above-mentioned extremely rugged terrain, a UAV-based magnetic survey was the preferred acquisition strategy. Data were acquired by rigidly fixing the magnetometer to the UAV landing sled, using a sensor with a very high-frequency (1000 Hz) acquisition rate. The acquisition strategy and some simple processing steps resulted in a detailed drone-borne total field anomaly map. This dataset allowed for a mapping of the dike outside the quarry area and the identification of a vent fed by the dike. The 2D forward modelling of the magnetic data was constrained by a field estimation of the intensity of the total magnetization and by the depth to the dike's top, in places where it is outcropping. • The drone-borne magnetic surveys, in some cases, are the only strategy for high-resolution investigations. • To increase flight security and stability, the magnetometer was rigidly attached to the drone's landing gear. • The goal of this work was to map an igneous dike intruded in sedimentary rocks in difficult ground conditions. [ABSTRACT FROM AUTHOR]

A device named magnetic susceptometer for a complete determination of the magnetic complex susceptibility of materials and minerals has been conceived and manufactured as a complement for the in situ characterization of rocks during high resolution magnetic prospections. In this work a device and its capabilities for susceptibility measurements are described, the calibration performed with artificial samples, and the values of real and imaginary susceptibility of natural samples in a range comprising: χ = 10 −4 to 10 −7 [SI], representative of Earth and also Mars rocks. [ABSTRACT FROM AUTHOR]

The Istituto Nazionale di Geofisica e Vulcanologia (INGV) has systematically undertaken the task of making measurements of the Earth's magnetic field in Italy. By tradition and because of the elongated geometric shape of our peninsula and islands, in Italy, a grid of more than 110 points, called the first order repeat stations, with an average spacing around 55-60 km, is in operation. Over this grid the measurements are repeated regularly, every 5 years. A survey of 131 repeat stations of the Italian Magnetic Network (including 2 observatories, 11 stations in Albania, 3 stations in Corsica and 1 in Malta) was carried out between 2009 and 2010 with the main purpose of updating our magnetic cartography. We describe the characteristics of magnetic first and second order networks, the magnetic measurements and the data reduction procedure. In agreement with the recommendations of MagNetE Committee, we report new repeat station data measured and reduced at 2010.0. An analytical expression, a second order polynomial, in latitude and longitude for the field elements, was determined, and coefficients for 2010.0 and average secular variation over the period 2005-2010, were obtained. The new maps for Italy, for D, F, H and Z at the epoch 2010.0, are shown. A selection of stations from the Italian Magnetic Network, based on their low values of anomaly with respect to a 'normal' field, is also proposed for future surveys.