This article discusses the problem of trend detection in time series generated by technical devices. The solution   to this problem is closely related to the problem of detecting coarse measurements (outliers), which negatively impact the accuracy of estimates of various physical quantities. These are crucial in many applications in various scientific fields in which the input data are observations, such as space geodynamics, geodesy, and others. Previously, the author proposed   a trend-detecting method based on the condition of maximizing the amount of data cleared of outliers and used in further   processing. The reference values used for trend construction are determined as a result of a completely convergent iterative process, the core of which is the minimizing sets method developed earlier by the author. This paper deals with the aspects of trend construction in the class of harmonic functions with unknown frequencies, phases and amplitudes.The main problem of trend construction in such a functional class is the nonlinear dependence of harmonics on the desired parameters, which does not allow to reduce the problem of trend search to the solution of a system of linear equations. The search for harmonics approximating the measurement data is carried out by the conjugate gradients method generalized to nonlinear problems. The efficiency of the method was tested on the test problem of trend construction in the data obtained by computer simulation.

The issues of metrological support of packet data transmission networks are considered. The main problems of traceability in the transmission of measurement units of parameters of packet data transmission networks to measuring instruments are described. The results of the analysis of the fleet of measuring instruments traceable to the State primary standard of units of quantity of transmitted (received) information (data) and units of values of parameters of packet data transmission networks GET 200-2023 are presented. The cardinal differences between the methods of measuring the parameters of packet networks implemented using GET 200-2023 or measuring instruments and working standards are considered. Network parameters that determine their integrity and stability include bandwidth, packet transmission delay, packet transmission delay variation, and packet loss coefficient. It is established that when measuring the parameters of networks with operational traffic, the fractal and avalanche-like behavior of packet communication networks complicates the application of statistical mathematics and classical error theory, and measurements turn into an iterative research process. It is shown that the method of using rigid logic implemented in GET 200-2023 to obtain a synchro pulse associated with a logical event allows avoiding the problem of uncertainty of the time of a logical event, characteristic of measuring instruments based on   software logic. A number of issues of metrological support for packet networks are noted, which are currently not covered by legislative acts and do not have an adequate technical solution. Government agencies in the field of legislative metrology and all interested parties are invited to pay attention to this.

The results of two radiotechnical experiments on measuring the parameters of the Earth's gravitational field using signals from low-orbit spacecraft and global navigation satellite systems are presented. The authors' previously proposed method of measuring the acceleration of gravity using signals from a low-orbit satellite, as well as the method of measuring  the current height of the geoid based on an onboard bistatic radar system, are experimentally verified. In the first experiment, a signal from the low-orbit small spacecraft RS-44 (DOSAAF-85) with a frequency of about 2.3 GHz was used, in the second experiment primary measurement data from a bistatic radar system installed on board a foreign satellite CYGNSS. As a result of processing the measurement results obtained in the first experiment, a difference was established between the measured and model values of the gravitational acceleration of the low-orbit spacecraft with a standard deviation of 6.3 mGal. Currently, gravity acceleration measurements based on mechanical gravimeters on board a satellite are impossible due to weightlessness. In the second experiment, the measured and model values of the geoid height profile differ from each other by 13.3 cm, which meets modern requirements. The method of measuring the current geoid height based on an onboard bistatic radar system, unlike the classical method of satellite radio altimetry, allows for up to 60 reflected signals and measured heights simultaneously. The experimental results can be used to refine the model of the Earth's gravity field in remote territories and water areas, including the Arctic region.

The paper presents the results of the development of a laser-optical system for atomic interferometer based on rubidium atoms cooled to sub-Doppler temperatures. The laser-optical scheme was created to ensure the processes of cooling, pumping, and detecting atoms involved in interferometric measurements of free-fall acceleration. The system utilizes frequency doubled fiber lasers and broadband fiber electro-optical modulators. The choice of fiber lasers is driven by their high efficiency, narrow spectral line, low phase noise levels, as well as ease of operation and reliability. Laser frequency stabilization was carried out using modulation transfer spectroscopy and optical phase-locking methods. Experimental setups were described that allow the generation of multichromatic radiation and minimize spontaneous scattering by detuning from excited levels. It was noted that the design provides a full set of optical frequencies necessary for Raman spectroscopy. The amplitudes of frequency fluctuations of the cooling and pumping lasers were studied. It was shown that the implemented laser-optical system can ensure continuous operation of an atomic interferometer based on clouds of cold rubidium atoms, and an assessment of the fundamental sensitivity limit was conducted.

The article formulates the problems of antenna calibration used for testing for electromagnetic compatibility.It is noted that the apparatus and calibration methods of test antennas existing in the Russian Federation do not allow for an effective achievement of EMC test goals, primarily due to high uncertainties of their antenna factor. To achieve the required accuracy of measurements of antenna characteristics and, as a result, electromagnetic compatibility parameters a High-precision measurement equipment for EMC antenna calibration are presented. The application of this equipment allows not only to carry out high-precision measurements of the characteristics of radiated industrial radio interference, but also to implement three classical methods of antenna measurements over a metal ground plane in a large semi-anechoic shielded chamber, as well as a method of measurements at close distances. Based on these methods, algorithms and methods for measuring the characteristics of antennas and antenna calibration test sites have been developed. The main results of the development are presented, including the results of experimental studies of the functionality and metrological characteristics of the measurement system using the example of precision resonant dipoles. The results obtained will be used to create the technical basis for a system to ensure the uniformity of measurements of the characteristics of antennas used for electromagnetic compatibility tests. The developed large polygonal semi-anechoic chamber can be considered as a reference test site of the Russian Federation and in the CIS countries, including during interlaboratory comparison tests.

Measurements of the granulometric composition of aerosols, suspensions and powdery materials in the field of ultrahigh concentrations are in demand in the chemical, gas, and oil industries, where concentrated suspensions of solid particles are used. The existing measuring instruments for particle number concentration in liquids are characterized by an upper limit of the reproduction range of particle number concentration of 10¹² m⁻³. However, for metrological support of photometric high-precision measuring instruments for the number concentration of particles in a liquid, it is necessary to expand this range to 10⁸‒10¹⁸ m⁻³. As part of the development of measures for calculating the concentration of particles in the liquid MSK-V, a technology for producing highly concentrated suspensions of monodisperse polystyrene latex spheres has been proposed. The high concentration of the suspension was achieved as a result of an increase in the amount of styrene in the seeded emulsion and, consequently, an increase in the amount of coagulate during synthesis. An algorithm for indirect measurements of the particle number concentration in aqueous suspensions of monodisperse polystyrene latex spheres is described. During the research, equipment from the State primary standard of units of dispersed parameters of aerosols, suspensions and powdery materials GET 163-2020 was used. The particle number concentrations and metrological characteristics of the created measures are determined. The levels of confidence of the error of indirect measurement of the number concentration of particles in water are calculated. It is established that the limits of the relative error of indirect measurements of the number concentration of particles in water are ±4 %. The developed measures of number concentrations of particles in a liquid (MSK-V) will partially cover the need of the domestic market for measures and standard samples for determining the size and number concentration of particles while ensuring the uniformity of measurements of the granulometric composition of aerosols, suspensions, and powdery materials.

For the metrological assurance of inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry, the process of establishing the calibration dependence of the output signal is of great importance. In this article, the authors present the results of work on the development of a reference material of the composition of a multicomponent solution of elements: barium, cadmium, cobalt, copper, iron, lead, lithium, manganese, nickel and zinc (ICP-RM Multi 2). The reference material is a solution of metals or their compounds acidified with nitric acid and packaged in cans made high pressure polyethylene complete with a hermetically sealed screw cap for long-term storage, with additional packaging of the lid in paraffin tape and vacuum packaging to reduce evaporation of the material through a threaded connection. This article presents the results of determining the metrological characteristics of reference material: long-term stability, homogeneity and uncertainty of characterization of the certified value based on the results of measurements on the State primary Standard of units of mass fraction and mass (molar) concentration of inorganic components in aqueous solutions based on gravimetric and spectral methods GET 217-2018. Тhe extended uncertainty of the certified value of the mass fraction and mass concentration of components in ICP-RM Multi 2 does not exceed 0.8 %, which corresponds to the category of working standards according to the state verification scheme of component content and will ensure metrological traceability of measurement results in inorganic analysis by mass spectrometry and optical emission spectrometry with inductively coupled plasma methods from the State primary standard GET 217-2018, and also to apply in routine analysis one of the main advantages of these methods is the ability to quickly and simultaneously measure several elements in samples.

In preparation for the reform of the International System of Units at the 26th General Conference on Weights and Measures in 2018, the Consultative Committee for Units of the International Committee for Weights and Measures proposed, along with changing the definitions of the four base units (kilogram, ampere, kelvin and mole), also changing the definition of the term unit of quantity. This proposal caused a wide discussion in the metrology community and was not accepted by the majority of participants in the discussion. It was decided to continue the discussion of this issue after the 26th General Conference on Weights and Measures. The article analyzes the definitions of the key metrological terms quantity, unit of quantity, value of quantity presented in the SI Brochure, the standards of the International Organization for Standardization, the International Vocabulary of Metrology and the proposals of the working group on key metrological terms created by the Consultative Committee for Units in 2019. It is shown that in all of the listed publications, the definitions of these terms have both physical, mathematical and linguistic inaccuracies and inconsistencies.

A brief description of the problems that arise in the measurement problems of assessing compliance with established requirements in the quality infrastructure is given, including in connection with the requirements of ISO/IEC 17025:2017(E) “General requirements for the competence of testing and calibration laboratories” for documenting and applying decision-making rules for determinative and control tests, taking into account possible risks. These problems are conventionally divided into two groups: problems of methods for solving measurement problems, on which discussions are still ongoing, and problems of conformity assessment procedures, for which the experience of control theory can be used. The first group includes the problems of uncertainty and precision of measurement, the inadequacy of measurement equations in the indirect measurement method, the loss of the property of freedom from distribution by the criteria of agreement in the statistical verification of complex hypotheses, the exclusion of outliers in measurement protocols and terminological contradictions. It is shown that the measurement tasks of assessing compliance with established requirements in the quality infrastructure can be formulated as typical problems of the theory of control. Therefore, the second group consists of problems that can be solved by methods for determining the completeness of control, setting tolerance limits for controlled parameters, and selecting the confidence level. Then it becomes possible to assess the risks of statistical assumptions, false positive and false negative decisions about compliance with established requirements based on mathematical models of control objects.

The wave number of the Raman shift is one of the most important parameters in Raman spectroscopy. Since the accuracy of determining the wave number of the Raman shift strongly depends on the technical characteristics of the Raman spectrometers and the measurement conditions, physically and chemically stable reference materials that would be convenient for users are required to calibrate such devices on the wave number scale. One of the promising areas of development of such reference materials that meet these requirements are solid-state reference materials developed in our country and abroad. A Raman shift wave number measure has been developed and tested for the purpose of approving the type of measuring instrument. The measure is intended for calibration and verification of measuring instruments on the scale of Raman shift wave numbers. The measure is a polymer film consisting of polystyrene and sulfur and placed in a special mandrel. The measure material is in a solid aggregate state. The metrological characteristics of the developed measure have been studied. It has been established that the measure allows storing and transmitting a unit of Raman shift wave numbers for Raman scattering excitation wavelengths of 532–785 nm in the range of 80–3000 cm^–1 with an error of no more than 1 cm^–1. Traceability is ensured to the State primary special standard of units of energy, energy density distribution, pulse duration and wavelength of laser radiation GET 187-2016 and the State working standard of the unit of wavelength for fiber-optic information transmission systems in the range of values from 0.4 to 3.4 μm (3.1.ZZA.0114.2018). The combination of polystyrene and sulfur lines in the Raman spectrum of the developed measure made it possible to expand (in comparison with the range of similar solid-state measures of foreign production) the range of wave numbers of Raman shifts, especially in the short-wave region.

Liquid crystal spatial light modulators are used in a wide range of modern problems in science and technology. These modulators are used to control the amplitude, phase, and direction of propagation of coherent optical radiation in optical information processing systems. However, the influence of the characteristics of the temporal dynamics of liquid crystal spatial light modulators on the performance of information optical systems, including diffractive neural networks, has not been sufficiently studied. The article presents the results of a study of the temporal dynamics of phase modulation of the liquid crystal spatial light modulator SLM-200 (Santec, Japan). Computer-synthesized binary phase diffractive optical elements were used in the experiments, and the characteristics of the temporal dynamics of the optical modulator were measured: 125 ms is the rise time of the diffraction efficiency when displaying diffractive optical elements on the screen; 61.9 ms is the decay time when switching frames. With these characteristics, it is possible to ensure the formation of a variable optical field at a frame display frequency of 2 Hz with an interference level of –17.1 dB. Increasing the frame display frequency leads to the appearance of unavoidable interframe interference, which in turn limits the effective performance of the information system. The results obtained can be useful in designing high-performance optical information processing systems and diffraction neural networks

The issues of metrological ensures for measurements of the spectral characteristics of radiation receivers in a wide spectral range, in particular from the ultraviolet to the terahertz range are consider. Until now, measurements of the spectral sensitivity of receivers in the wavelength range greater than 14 μm have not been metrologically supported, which their use for measuring the power of terahertz radiation when solving problems in the field of medicine, safety and climatology excluded. A reference receiver of terahertz radiation has been developed, manufactured and studied in order to solve the problem of reproducing and transmitting the unit of spectral sensitivity of radiation receivers in the wavelength range of 14–300 μm with traceability to an absolute cryogenic radiometer. The operating principle and design of the developed receiver are described, its metrological characteristics are studied and presented. The components of the uncertainty of the reproduction of the unit of spectral sensitivity of the reference receiver of terahertz radiation are calculated. The uncertainty budget for the reproduction of the unit of spectral sensitivity in the wavelength range of 14–300 μm is presented. An installation based on a monochromatic source of terahertz radiation and a standard receiver of terahertz radiation have been developed. The installation is designed to transfer a unit of spectral sensitivity to receivers of terahertz radiation. The research results are of great importance for many branches of science and technology, since spectral sensitivity measurements are widely used in astrophysics, lighting engineering, geophysics, biophysics, biology, medicine, agriculture, chemistry, metallurgy, etc.

The main optical characteristic of pyrometers is the dependence of the diameter of the circle of the pyrometer’s field of view on the distance between the pyrometer and the object being measured. This dependence is not possible to be calculated strictly currently, so it has to be measured experimentally. The diameter of the field of view circle can be determined using circular (iris) and slit diaphragm methods. In the first method, the results of measurements of the diameter of a variable iris diaphragm, fitted near the emitter outlet, are used, and in the second method the results of measurements of the width of a slit diaphragm, also fitted near the emitter outlet and moved in a plane which is perpendicular to the optical axis of the pyrometer, are used. The results obtained using these two methods somewhat differ from each other because of difference of areas of the iris diaphragm and in the surface cut by the slit diaphragm, the width of the slit being equal to the diameter of the iris diaphragm. The relationship has been established linking the results obtained by the mentioned methods of a circular diaphragm and a slit diaphragm. This enables to correctly measure the diameter of the field of view circle using the slit diaphragm method, which is faster and less labor-intensive than the iris diaphragm method. The obtained results are relevant for contactless temperature measurements performed in technological processes as well as in research and development work.

Changes in the structural parameters and physical and mechanical properties of a ferromagnetic material are reliably monitored using its intrinsic demagnetization coefficient, which arises due to mechanical stresses, inhomogeneities in the structure and anisotropy of the material. However, the determination of the internal demagnetization coefficient of a material requires a cycle of anhysteretic magnetization of thermally demagnetized material with precision measurements of its magnetization and subsequent statistical processing of the measurement results, which reduces the reliability and complicates the use of this coefficient in magnetic structuroscopy. When analyzing the relationship between the internal demagnetization coefficient of a ferromagnetic material and the parameters of the limiting loop of its magnetic hysteresis, the formula for indirect determination of the internal demagnetization coefficient of a ferromagnetic material by its coercivity, residual magnetization and technical saturation magnetization, derived earlier by the author, was used. The influence of heat treatment modes, chemical composition of steels and the ratio between their magnetic parameters on the structural heterogeneity of the studied materials is analyzed. The influence of heat treatment modes, chemical composition of steels and the ratio between their magnetic parameters on the structural heterogeneity of the studied materials is analyzed. An example of analysis of functional dependences and the range of possible changes in the internal demagnetization coefficient of a material at changes in its magnetic parameters in practically important ranges is given. The influence of carbon content in carbon steels on their internal demagnetization coefficient is studied. For the heat-resistant medium-carbon alloyed steel of 34CrMo4 grade, widely used in machine-building in the manufacture of forgings and fasteners, the range of quenching temperature variation, which provides the maximum structural heterogeneity of the quenched steel, has been established. It is shown that in the whole range of changes in tempering temperature of 34CrMo4 steel after quenching, the dependence of the internal demagnetization coefficient on these changes is monotonic. As a result of this study, the indirect determination of the internal demagnetization coefficient according to the proposed formula can be recommended for non-destructive control of tempering temperature of 34CrMo4 steel.

In connection with the planned comparisons of AC and DC voltage standards based on the quantum Josephson effect by the International Bureau of Weights and Measures in accordance with the Technical Protocol of Comparisons BIPM.EM-K10, the possibility of a programmable Josephson voltage array from the State Primary Standard of the Unit of Electric Voltage GET 13-2023 for measuring sinusoidal voltages of 0.75 V and 7 V in the frequency range of 62.5–1000.0 Hz was investigated. When measuring voltages in the frequency range of 62.5–200.0 Hz, a digital voltmeter with specially developed software for measuring AC voltage was used together with the quantum voltage standard. The obtained results differ from the measurement results presented in the Technical Protocol of Comparisons. However, the results of the conducted study confirmed the possibility of using a quantum voltage standard based on a programmable Josephson array from GET 13-2023 for comparisons based on the specified Technical Protocol. The interaction of the quantum voltage standard and the AC voltage source was analyzed, and a conclusion was made on the need to control the reproduced AC voltage with a digital voltmeter with the software recommended in the Technical Protocol for comparisons.