The operation of flux-gate magnetometers (FGMs) onboard moving carriers faces several difficulties that limit their application in geophysics. Specifically, when FGM is used onboard UAV (such as drone) it has essential space rotation. As we show in the paper, it may create interference up to the value overcoming the useful signal. We show that the obstacles limiting the FGM sensitivity threshold are the FGM axes non-orthogonality and its sensors transformation factor non-uniformity. A possible solution of this problem is proposed: not to try to make these values as small as possible, but to determine them after production at thorough calibration and then use them at data processing. A new method to determine the real FGM channels mutual orthogonality deflection and transformation factors non-identity with given precision is described and experimentally confirmed.

Assessment of a power lines condition is an important task for all countries. It includes GPS mapping of the: 1) wire breaks; 2) places of the increased current leakage, for example corona detection; 3) degree of wires sagging between power line towers; 4) location and conditions of the power line towers; 5) vegetation encroachment along a power line corridor. Considering that power line currents, including leakage currents, create strong magnetic field, use of magnetometers in the range from DC to sound frequencies for the solution of tasks 1-4 is highly prospective. At the same time, it is possible the control of the vegetation critical proximity to a power line adjacent zone by the increased leakage current (threats of the increased leakage current or breakdown to a tree crown). Thus the task 5 also can be solved. The goal of the present report is to introduce the new design of miniature low-weight three-component sensor for measurement of alternative vector magnetic field onboard UAV – induction magnetometer (IM) - with autonomous system including two-component tiltmeter and GPS antenna inside in order to obtain precise measurement timing, UAV coordinates and altitude during movement. These data are stored in the SD memory card. Construction details, tests results and technical specifications of this IM for are presented.

Electromagnetic compatibility (EMC) is an important requirement for spacecrafts due to the limitation of their volume and the possibilities of the layout of individual subsystems. Interference from satellite service systems are the main problem in conducting high-sensitivity measurements of magnetic fields when studying wave processes in plasma in the range of low frequencies. This is especially true for the becoming recently popular very small satellites - CubeSats (CS) with sensitive equipment for measuring electric and magnetic fields in the range from direct current to low frequencies. In order to minimize the mutual influence of the payload and service systems, it is necessary to determine the frequency and amplitude of the main spectral components of the emitted magnetic field of each satellite subsystem to reduce the level of the interference or, if not possible, to take into account when processing data. A special measuring system, created for registration and estimation of magnetic interference in the ULF range, is described in the article. This system consists of two identical three-component induction magnetometers, data acquisition unit, power supply unit, and control computer with a corresponding set of programs. With this system, the level of the AC magnetic field, generated by each of the subsystems of the CS, was measured and digital processing was performed. For the separation of the studied and background signals, data obtained from two identical three-component induction magnetometers of the system were used with the following solution of the inverse problem the determination of the parameters of the radiation source using the measured magnetic field generated by this source at two points. The results of the EMC tests for the CS developed under the SEAM project, the values and locations of the equivalent magnetic dipoles of the radiation of the separate subsystems, which are the sources of radiation in the CS, are given.

The copters are the recent challenge and many instruments are attempted to be used with them, including magnetometers. The last is a pending problem, especially for component magnetometers, because of the complexity of reducing the data obtained in permanently rotating frame system to the data in geomagnetic frame system. Next problem is high interference level due to copterelectrical circuits and its moving metal parts during magnetometer operation. A possible approach to the first problem solution is presented.

Small weight and dimensions of the micro- and nanosatellites constrain researchers to place electromagnetic sensors on short booms or on the satellite body. Therefore the electromagnetic cleanliness of such satellites becomes a central question. This paper describes the theoretical base and practical techniques for determining the parameters of DC and very low frequency magnetic interference sources. One of such sources is satellite magnetization, the reduction of which improves the accuracy and stability of the attitude control system. We present design solutions for magnetically clean spacecraft, testing equipment, and technology for magnetic moment measurements, which are more convenient, efficient, and accurate than the conventional ones.

The profession of a miner is one of the most dangerous in the world. Among the main causes of fatalities in underground coal mines are the delayed alert of the accident and the lack of information regarding the actual location of the miners after the accident. In an emergency situation (failure or destruction of underground infrastructure), personnel search behind and beneath blockage needs to be performed urgently. However, none of the standard technologies – radio-frequency identification (RFID), Digital Enhanced Cordless Telecommunications (DECT), Wi-Fi, emitting cables, which use the stationary technical devices in mines – provide information about the miners location with the necessary precision. The only technology that is able to provide guaranteed delivery of messages to mine personnel, regardless of their location and under any destruction in the mine, is low-frequency radio technology, which is able to operate through the thickness of rocks even if they are wet. The proposed new system for miner localization is based on solving the inverse problem of determining the magnetic field source coordinates using the data of magnetic field measurements. This approach is based on the measurement of the magnetic field radiated by the miner's responder beacon using two fixed and spaced three-component magnetic field receivers and the inverse problem solution. As a result, a working model of the system for miner's beacon search and localization (MILES – MIner's Location Emergency System) was developed and successfully tested. This paper presents the most important aspects of this development and the results of experimental tests.

The electromagnetic cleanliness becomes first priority problem for small satellites with very compact design, especially for CubeSats, what greatly impedes their application for scientific research, especially for electromagnetic ones. The analysis of electromagnetic interferences sources is given and the ways how to decrease their influence at satellite design are recommended. The instrument for electromagnetic cleanliness measurement and its operation algorithm are proposed.

The ways of decreasing the flux-gate magnetometer temperature zero drift are studied. A new method to decrease the drift by creating a special configuration of measured magnetic field compensation field is proposed. The principle of the functional diagram of the system for scientific information processing and collection (SSIC) building for nano-satellites is designed. High-speed interface for data transfer from SSIC to radio line is developed. A large amount of data from microsatellite "Chibis M" and experiment "Variant" on board the satellite "Sich-1M", which were registered by onboard instruments manufactured in LC ISR, are processed. An emission from power lines at the frequency of 50 (60) Hz and Schumann resonances modes which are penetrating to the ionosphere above the F2 layer were observed in these experiments.

The possible effects of technogenic impacts on the ionosphere, with the continuing trend towards its sustainable growth, are unknown today. It is therefore very important and urgent task to conduct statistically valid research related to the study of variations of ionospheric parameters due to the influence of powerful technogenic factors, primarily due to a significant increase of the electromagnetic energy production. In this paper, we discuss new results of observations of electromagnetic fields in the ionosphere at the power lines main frequency of 50 (60) Hz and its harmonics onboard SICH-1M (2004) and CHIBIS-M (2012–2014) satellites. The spatial distribution of the observed phenomena and their connection with possible ground-based sources–powerful transmission lines is presented. It is concluded that organization of regular monitoring of technogenic fields may allow continuous control of energy consumption in both the local (within a country or even a powerful consumer) and global scales.

The power line emission (PLE) 50/60Hz and the Schumann resonance (SR) harmonics were detected by the use of a compact electrical field sensor of length 0.42m during microsatellite Chibis-M mission in years 2012-2014. The initial orbit of Chibis-M has altitude 500km and inclination 52 degrees. We present the space distribution of PLE and its connections with the possible overhead power lines. PLE has been recorded both in the shade and sunlit parts of the orbits as opposed to SR which have been recorded only in the nightside of the Earth. The cases of an extra long distance of PLE propagation in the Earth's ionosphere and increased value of SR Q factor have been also observed. These results should stimulate the ionosphere model refinement for ultralow frequency and extremely low frequency electromagnetic wave propagation as well as a study on new possibility of the ionosphere diagnostics.

The reduction of financial support of space scientific research forces the scientists to develop new small spacecrafts for the experiments realization. The most popular recently are cubesats which are available as commercial construction kit with the size 10×10×10 cm, by this several cubes (nU) may be connected together. But with such kits mostly technological and demonstration experiments may be realized. To create scientific grade structure able to provide high resolution measurements within so small volume it is necessary to solve several important problems, between which the most complicated one is providing electromagnetic compatibility of all units composing the nU cubesat and electromagnetic cleanliness (EMC) of all structure. The goal of this report is to outline the problems connected with the EMC procurement within so small and densely packed volume. Also a dedicated system development which will be able to determine the electromagnetic interference sources location and their radiated power is described. The results of experimental works realized with such a system during the development of 3U cubesat for electromagnetic study in space plasma are discussed.

Lithospheric ultra low frequency (ULF) magnetic activity is recently considered as very promising candidate for application to short-time earthquake (EQ) forecasting. However the intensity of the ULF lithospheric magnetic field is very weak and often masked by much stronger ionospheric and magnetospheric signals. The study of pre-EQ magnetic activity before the occurrence of strong EQ is a very hard problem which consists of the identification and localization of weak signal sources in EQ-hazardous areas of the Earth's crust. A new approach is developed to find a source of pre-EQ ULF electromagnetic activity of lithospheric origin. For separation and localization of such sources a new polarization ellipse technique has been used to process data acquired from 3-component magnetometers. The polarization ellipse is formed by the magnetic field components at the measurement station. Calculations based on polarization ellipse parameters from two distant points allow discrimination of seismo-EM signals from natural background ULF signals. The results of experimental verification of this method in Kanto region (Japan), known as one of the most seismoactive, are given which partially confirm its efficiency and give hope, with its further improvement, to the progress in the EQ precursors reliable detection in other regions of the Globe, particularly, in Iceland known by the active seismic activity.

A new approach is developed to find a source of pre-EQ ULF electromagnetic activity of lithospheric origin. For separation and localization of EQ magnetic precursors a new polarization ellipse technique has been developed to process the measurements data acquired from 3-component magnetometers.