An analysis is made of the known methods for calibrating and evaluating the parameters of implemented space gradiometers. There are 4 main stages: laboratory assessment of amendments, assessment of amendments during operation, assessment of amendments from independent data, calibration. A description of each step is provided. Two methods for calibrating space gradiometers are proposed: based on a complex of calibration sites and an onboard stand. The principles of building elements of a complex of calibration sites are investigated and their structure is formed. The analysis of the possibility of using the onboard mass on board the spacecraft for calibrating the space gradiometer is carried out. The main parameters of the onboard stand are highlighted. Scope: determination of metrological characteristics of space gravitational gradiometers.

The article presents the results on development of an algorithm and a program for calculation in ultra-rapid regime of ephemeris-time information for GLONASS and GPS navigation satellites, achieved by now in the Main metrological center of the state service of time and frequency and determination of earth rotation parameters of VNIIFTRI. Calculation of ephemeris-time information is carried out by data of code and phase measurements at two carrier frequencies. The measurement data are presented in the form of hourly RINEX observation files and navigation message files from tracking stations involved in the IGS (International GNSS Service) network. Results of test calculations of ephemeris and clock corrections of GLONASS and GPS navigation satellites are presented. The analysis of the accuracy of the obtained results compared to the aposteriori data of other analysis centers is given.

The basic mathematical provisions that determine the necessary and sufficient conditions for the application of the method of linearization of nonlinear functions of random arguments in the evaluation of errors of the results of indirect measurements are considered, and the need to present the assessment of the arising systematic component of the error and the degree of approximate representation of functions is noted. Within the framework of the necessary and sufficient conditions for the expansion of an arbitrary function into a Taylor series, a new analytical formula for the approximation of a nonlinear function in the form of a quotient of independent random arguments is obtained, which allows to exclude the questions of refinement of the results by adding terms to the Taylor series and estimating the degree of approximation of a nonlinear function by the values of the corresponding residual terms when evaluating the errors of indirect measurements. It is shown that the obtained new approximation for the replacement of such a function allows us to determine the practical conditions under which to estimate the errors of the corresponding results it is possible to use known, and quite simple, formulas for estimating the absolute and relative errors without preprocessing the results of direct measurements.

The main problems of metrological support of speed and throughput measurements in digital packet data networks are considered. The measures for performing data rate measurements are listed. Various ways of ensuring traceability of digital information transmission rate meters are proposed, such as modernization of the existing GET 200-2012, development of the primary reference method of speed measurements and creation of a local verification scheme for digital information transmission rate measurements. Recommendations on the implementation of the chosen method of ensuring traceability of data rate meters and throughput of communication channels are given. The proposed approaches can be applied in the Metrology of digital communication systems.

The problems requiring high-precision measurements of signal propagation delays in optical fibers are considered. Design features of a pulsed optical reflectometer with a picosecond resolution designed for measuring propagation delays of a signal are considered. It is shown that the error of such a reflectometer includes the additive and multiplicative components. A method for determining the additive component of the optical reflectometer error based on measurements of signal delays introduced by individual optical fiber coils and the total delay introduced by series-connected coils is proposed. The requirements to the measurement conditions are formulated and the results of the error estimation of the proposed method are presented. To exclude the multiplicative component of the reflectometer error, a method for determining corrections to the reflectometer readings is proposed. The method is based on measuring the propagation delays of the signal in the coils of the optical fiber, first using reference equipment (installation for measuring the propagation delay of the signal), and then using an optical reflectometer, and then calculating the differences of the obtained measurement results. The scheme of installation for measurements of a propagation delay of signal in a coil of optical fiber is presented, the principle of operation of measuring installation is described. The results of the estimation of the error in determining the corrections to the reflectometer readings by the proposed method are presented. It is shown that the exclusion of the additive and multiplicative components of the error will reduce the error of optical reflectometers to values less than ± 100 ps.

The latest changes in the algorithm for the formation of the international atomic time scale TAI are reported in terms of estimating the weights of the clocks involved in the formation of TAI. Studies of the characteristics of the long-term instability of new-generation hydrogen masers based on processing the results of the clock frequency difference with respect to TAI are performed. It has been confirmed that at present, new-generation hydrogen masers show significantly less long-term instability in comparison with quantum frequency standards of similar and other types.

The results of improvement of programs and methods of Earth’s orientation parameters (EOP) combination of vary long baseline interferometry (VLBI), global navigation satellite systems (GNSS) and satillite laser ranging (SLR) in Main Metrological Center of State Service for Time, Frequency and Earth’s orientation parameters evaluation are considered. Nowdays, the combination of different geodetic thecnics measurements in Main Metrological Center of State Service for time, frequency and Earth’s orientation parameters evaluation is provided both at the time raws level, and on the observations level. The increasing accuracy of Universal time UT1 was caused by using in combination observational data from new thirteen-meter antennas of the two-element very long base interferometer which was created in Institute of Applayed Astronomy of Russian Academy of Science. In general, increase in accuracy of combination values of the Earth’s orientation parameters was caused both by the increase in accuracy of the separate time raws, and by the improving of the combination algorithms.

Relative acoustic gas thermometry setup is described. Described setup was developed and tested in VNIIFTRI. The setup is designed for the measurement of thermodynamic temperature in low temperature range down to 4,2 K. Main part of the setup is resonator with reduced cavity diameter. Reduction of resonator dimension lead to several times reduction of cooled parts of the setup with respect to the setup previously developed in VNIIFTRI. This decreases liquid nitrogen and liquid helium consumption required for cooling of resonator. Moreover, reduction of the mass of cooling parts reduces time required for temperature stabilization and thus measurement time. In the work the tests’ results of operation of main parts of the setup are presented.

The possibility of using bolometric converters of microwave power from the State primary standard of the unit of power of electromagnetic waves in waveguide and coaxial paths GET 167-2017, which has a frequency range from 37,5 to 78,33 GHz, in an extended frequency range up to 220 GHz, is shown. Studies of semiconductor bolometric converters of microwave power in an extended frequency range have confirmed good agreement and smooth frequency characteristics of the effective efficiency factor of the converters. Based on the research results, the State working standard of the unit of power of electromagnetic waves of 0,1–10 mW in the frequency range from 37,5 to 220 GHz 3.1.ZZT.0288.2018 was approved. The technical characteristics of the working standard of the unit of power of electromagnetic oscillations in an extended frequency range from 37,5 to 220 GHz are given.

The analysis of the current state of the reflection coefficient measurements in waveguides at millimeter waves is carried out. An approach for solving the  problem of reproducing the reflection coefficient measurement scale is proposed. Mathematical equations, which are the basis of the reflection coefficient measurement equation are obtained. The method of determining the metrological performance of reflection coefficient unit’s reference standards is developed. The results of electrodynamic modeling and analytical calculations by the developed method are compared. It is shown that this method can be used for reproducing the reflection coefficient unit in the development of the State primary standard.

A measuring facility for reproducing a unit of sound pressure at frequencies of 1–500 Hz in the temperature range of 0.5–35 °С with excessive static pressures up to 60 MPa is described. The measuring facility was created in order to expand the functionality of the State primary standard GET 55-2017. The expediency of simulated ocean conditions in GET 55-2017 under hydrophone calibration, the principles of operation and the metrological characteristics of the measuring facility are discussed. Features of the measuring procedure for calibrating the hydrophone are given

The approach to creating standard means for reproducing units of volumetric activity of radon and thoron and flux density of radon from the soil surface is described based on the physical principles of reproducing these units of quantities and using as technical means for reproducing bubblers with a radioactive solution of radium salt, reference capacities of known volume, emanation chambers for generation of a toron, a gamma spectrometer with a semiconductor detector from highly pure germanium and radon radiometers. Reproduction consists in the physical realization of units in accordance with their definition as applied to the formation of radon and thoron in the radioactive rows of radium and thorium. The proposed approach will allow to determine the structural, structural and other technical solutions of standard measuring instruments, as well as specific techniques and methods of working with them. The creation of standard tools and technologies for reproducing units of volumetric activity of radon and thoron and the density of radon flux from the soil surface will ensure the unity and reliability of measurements in the field of ionizing radiation, traceability of units and bringing the characteristics of national standards in line with world achievements