The relevance of research on the reproduction and transmission of the acceleration unit in gravimetry is determined by the development of measuring instruments for the absolute value of the acceleration of free fall and its changes. Qualitative and quantitative changes in the instrument base are due to the requirements of applied tasks solved using gravimetric data in such fields as geodesy, navigation, geodynamics, as well as the expansion of the field of practical application of absolute gravimeters. At the same time, in order to solve applied problems, along with accuracy requirements at a level close to the maximum achievable at the current level of technology development, maximum territorial coverage of measurement sites within the entire territory of the Russian Federation is often necessary. The accuracy of the results obtained with the help of measuring instruments is determined by the level of their metrological support, the main stages of which are the reproduction of the corresponding unit by the standard and its transfer to the measuring instrument. An analysis of possible sources of errors in gravimetric equipment has shown that when reproducing and transmitting the acceleration unit in gravimetry, it is necessary to take into account the influence of geophysical factors that manifest themselves as additional accelerations of a gravitational or inertial nature. The distribution of the gravitational field within a gravimetric point can manifest itself as an additional constant acceleration. Seismic processes and lunar and solar tides manifest themselves as variable accelerations. For various stages of metrological support of gravimetric devices, the mechanisms of the effects of such accelerations have been studied, as well as methods for accounting and reducing their influence using additional equipment have been developed. An additional gravimetric point with a cryogenic relative gravimeter and a broadband seismometer, as well as transported absolute ballistic and relative quartz gravimeters, were introduced into the State primary special standard of acceleration units in the field of gravimetry GET 190-2023.

The metrological support of optical-electronic means of measuring spatial coordinates is described. To meet modern consumer requirements for the accuracy of measurements of spatial coordinates with electronic tacheometers and their analogues (laser scanners, absolute trackers), the State primary special standard of the unit of length GET 199-2024 includes technical means for reproducing, storing and transmitting the unit of length in three-dimensional measurement mode. A reference complex of three-dimensional measurements (coordinate measurements, coordinate increments) has been developed and studied. The means and methods for transmitting a unit of length are presented, as well as the metrological characteristics of the GET 199-2024 in the mode of measuring coordinate increments (length). The sources of non-excluded systematic error and the standard deviation of the measurement result are determined.  As a result of the research performed, it became possible to reproduce a unit of length in the mode of measuring coordinate increments in the range of 0–60 m with a standard deviation of no more than 25 μm for 10 independent measurements and a non-excluded systematic error (with a confidence probability of 0.99) of 19 μm. The functionality of the GET 199-2024 will allow solving current problems of metrological support for high-precision electronic total stations and their analogues in three-dimensional measurement mode.

The problems of metrological support for high-precision torque measuring instruments, which have a measurement range that includes torque values of less than 1.0 N·m, are considered. The areas of activity in which torque measurements are important are shown. The history of the development of the highest level reference base as an important link in the metrological support of torque measurements in the Russian Federation is described. Brief information is provided on the level of development of the reference base in this field of measurements abroad. As a result of the increase in the number of torque measuring instruments, the upper measurement limit of which is less than 1.0 N·m, there was a need to expand the measuring and calibration capabilities of the Russian Federation in this area, in particular, in the range of 0.1–1.0 N·m. The composition of the State primary standard for the unit of torque GET 149-2023 is given. The operating principles of the four reference installations included in GET 149-2023 and the structure of the reference are described. GET 149-2023 includes the created modern reference installation EU-250-2 for reproducing, storing and transmitting a unit of torque in the range of 0.1–200 N∙m. The results of studies of the reference installation EU-250-2 and the metrological characteristics of GET 149-2023 are presented.

Two-syllabic terms of metrology are considered, which have become so firmly embedded in the mentality and practice of metrologists that the inadequacy of these terms manifests itself only when it is not possible to solve any important problem. Such a problem within the framework of the moment approach to estimating accuracy turned out to be the calculation of definitive uncertainty, and the term-phrase direct measurements causes a number of paradigmatic associations – indirect, cumulative, joint and other pseudomorphic measurements, similar in form of names and different in definition. But the errors of the results of these measurements can no longer be estimated in the same way as the errors of measuring instruments are estimated. The semantics of such two-syllabic terms is analyzed. The role of the direct and figurative meaning of the word measurement in the problem of the inadequacy of models is shown, the solution of which, within the framework of the compositional approach to assessing accuracy, is indicated by the word method before the two-syllabic names listed above. Bringing the term measuring problem into line with the semantics of the word problem has become the simplest correction of this terminological misunderstanding. At the same time, the inconsistency of the subordinate terms measurement method and method of solving the measurement problem has been eliminated.

The research presented in the article is aimed at reducing losses in the magnetic circuits of electrical machines. These losses amount to up to 5 % of the generated electricity, do not depend on the load and can increase over the life of the equipment. To effectively design and construct transformers with low no-load losses, total losses in steel are minimized by optimizing the crystal grain size and thickness of core sheets, improving the steel texture and magnetic circuit design, etc. However, the hysteresis, classical eddy current and anomalous eddy current components of losses in steel react in different directions to these measures, which does not effectively minimize total losses. To determine the three components of losses, a modernized method of three frequencies is proposed, which takes into account the dependence of the hysteresis loss coefficient on frequency. A formula for correcting this coefficient is derived. It is shown that the indicator of the degree of magnetic induction given in most modern scientific sources in the expression for eddy current anomalous losses has become irrelevant. A method for calculating this indicator for the core of a specific transformer is presented, which uses the loss components and total losses in steel found by the method of three frequencies and the total losses in steel at a reduced primary voltage. For the transformer under study, the degree of magnetic induction in anomalous losses was 1.88. The results obtained can be used in the design of dry and oil transformers of different powers operating with a sinusoidal magnetic flux.

Measurements of carrier frequency phase differences of global navigation satellite system signals between multiple antennas are used in many coordinate and navigation applications. Global navigation satellite systems signal simulators are used for controlling global navigation satellite systems receiver’s instrumental errors. Therefore, it is necessary to determine the systematic error of the carrier frequency phase of generated signals for signal simulators. For this purpose a new calibration method of global navigation satellite systems simulators was developed. Method is based on refined errors model of generated phase differences of two radio frequency channels of the simulator. The proposed method was implemented using a wideband oscilloscope as an analog-to-digital converter. Approbation of the calibration method was carried out by comparison with the measurement results obtained using the State secondary standard of units of complex transmission coefficients in the range of 0...–60 dB and complex reflection coefficients in the range of 0.002–1 in the frequency range of 0.05–65 GHz (registration No. 2.1.ZZT.0210.2015). The calibration method allows one to determine carrier frequencies phase offsets of navigation signals for global navigation satellite systems simulators with expanded uncertainty (with a coverage factor of 3) of 1°. The proposed method provides the required accuracy of generating phase differences of the carrier frequencies of global navigation satellite systems signals is ensured for modern types of global navigation satellite systems simulators.

The synchronization methods used in the pulse generators of the G5 measuring group in the external trigger mode are analyzed. The factors determining the error in the formation of time intervals in this mode have been studied. It is shown that the main source of errors in the formation of time intervals during external triggering of measuring pulse generators is the variation in the position of the clock generator reference pulses relative to the external trigger pulses. An analytical review of synchronization methods based on the sampling of time intervals by a multi-tap delay line as a pulse signal propagates along it is carried out. The method of instantaneous synchronization of output pulses is proposed, using sampling of the period of the reference pulses of the clock generator with a multi-tap delay line and fixing the position of the edge of the external trigger pulse within the period of the reference frequency by triggers that control the multiplexer, which connects the output of the multi-tap delay line to the output of the device, at which the edge of the next reference clock pulse generator lags by a minimum time from the front of the external trigger pulse. A device is presented that makes it possible to implement the proposed solution. The simulation of the device was carried out, illustrating the details of its functioning. Jitter was assessed on a prototype device using an integrated 5-tap delay line with a total delay of 20 ns. The method can be applied in measuring pulse generators and belongs to the field of pulse technology.

The problem of taking into account the influence of air on the properties of distilled water is considered, namely the lack of a single generally accepted method for calculating such an influence. The sensitivity of the structure of water to the influence of external factors is described and the possibility of recording and studying such factors by changes in the temperature coefficient of electrical conductivity of water is shown. The dependences of the temperature coefficient of electrical conductivity of distilled water on the rate of change in water temperature, the degree of filling of conductometric cells, as well as on the intensity of the exchange of carbon dioxide between water and air across their interface have been studied. It is noted that these metabolic processes are currently insufficiently studied. A hardware-software measuring complex has been developed and manufactured to study the temperature coefficient of electrical conductivity of water when its temperature changes within the range of 20–55 °C. The temperature coefficient of electrical conductivity of water in sealed conductometric cells was measured at different degrees of filling the cells with distilled water and the rate of heating and cooling of water. The degree of filling of the cells varied within the range of 10–100 %, the rate of change in water temperature varied within the range of 0.04–2.00 °C/min. With a constant heating and cooling time of 15 minutes in all experiments, the change in speed was achieved by changing the temperature of the heating element. The integral temperature coefficient of electrical conductivity is calculated based on the initial and final values of electrical conductivity and water temperature in each measurement cycle. The dependences of the temperature coefficient of electrical conductivity on the rate of change in water temperature at several constant degrees of cell filling were obtained. It has been shown that with a constant ratio of the volumes of water and air in the cell and an increase in the rate of heating of water, the temperature coefficient of electrical conductivity of water decreases by 19–22 %. It has been established that at a constant rate of water heating, with a decrease in the volume of water in the cell, the temperature coefficient of electrical conductivity of water decreases by 40–42 %. The results obtained can be used to quantify the dissociation coefficient of carbonic acid, the mobility of hydrogen ions, as well as the intensity of the gas exchange process under various external influences on water. Refinement of data on the electrical conductive properties of water and processes at the water/air interface is necessary for the development of models of atmospheric phenomena and climate change, as well as for the creation of sensors for weak changes in environmental parameters for the purposes of both environmental monitoring and medical diagnostics.

The modern concept of metrological assurance for gas analytical measuring instruments with the use of reference materials of gas mixtures composition in cylinders under pressure is presented. The reference materials of gas mixtures composition of approved type in cylinders under pressure, which are the most often means of mole fraction and mass concentration units transfer in gas analytical measurements, are considered. The certified value in these reference materials is the content of the target component (or components) in the gas medium (analytical matrix). All the produced reference materials of gas mixtures composition, which are used for ensuring the uniformity of measurements are traceable to the State primary standard of units of mole fraction, mass fraction and mass concentration of components in gas and gas condensate media GET 154-2019, which characteristics are confirmed on the international level by the results of about 90 international comparisons. The paper presents a methodology for ensuring metrological traceability of reference materials of gas mixtures composition using GET 154-2019, taking into account the constantly increasing park of gas analytical instruments and the emergence of new measuring tasks in various fields of industry and environmental control. Currently, a park of secondary and working standards has been created at enterprises producing reference materials of gas mixtures composition, and their traceability to GET 154-2019 has been implemented according to the state verification scheme. The paper presents the results of international comparisons with participation of GET 154-2019, confirming the comparability of the obtained and reference value of the target component content in reference gas mixtures at the international level. The variety and large number of relevant gas analytical measurement tasks in various industries and the social sphere determines the need to choose priority areas for improving the existing reference base, including the structure of the GET 154 Standard and the nomenclature of reference gas mixtures. The strategic program of the Gas Analysis working group of the Consultative Committee of the Amount of Substance of the International Bureau of Weights and Measures developed for the period up to 2030 has been analysed and a review of the long-term tasks of gas analytical measurements is given. The currently existing GET 154-2019 Standard of the latest generation provides reproduction, storage and transfer of the components’ mole fraction units in gas and gas condensate media in the range from 1.5·10 –8 to 99.99999 %, and mass concentration units in the range from 1.0·10–6 to 2.0·105 mg/m3, what is confirmed by the results of participation in international comparisons and published CMC positions in the International database of calibration and measurement capabilities (about 400 CMCs positions).

The results of key comparison are the most convincing and objective indicator of confirmation of the correctness and accuracy of the newly developed measurement method. The results of comparison and measurement methods applied at the second key comparison of national standards of the unit of sound pressure in water CCAUV.W-K2, organized by the Consultative Committee for Acoustics, Ultrasound and Vibration of the International Committee for Weights and Measures, are described. A feature of the comparison is that the calibration range has been expanded into the low frequency region by two octaves compared to the first key comparison CCAUV.W-K1. The results of the CCAUV.W-K2 comparison were considered successful. Important scientific results of participation in the comparison were confirmation of: the correctness of the hydrophone free-field calibration methods developed at VNIIFTRI (at ultra-low frequencies for a sound-reflecting water tank and in the noise reverberant sound field of the water tank), the equivalence of the calibration results when radiating signals of various types: chirp, noise and ton-burst. In the process of performing control calibrations, the pilot laboratory discovered violations of the stability of the reference hydrophone of comparison. When comparing the results obtained by participants, there was an increase in the discrepancy between the results in the frequency range 60–100 kHz, which is considered the least problematic.