Results of works on improvement of the state primary special measurement standard of ultrasound power unit in water GET 169-2005 are given. As a result of the inclusion of two new reference ultrasound power meters in the standard, the frequency and dynamic ranges of reproduction and transmission of the power unit to lower-level measuring instruments were expanded using absorbing targets for measuring the radiation effect of the ultrasonic wave and the absorbed ultrasonic energy. That is very important for metrological support of modern high-tech medical ultrasound equipment, including focused high-intensity ultrasound beams for the treatment of cancer. The automation of the measurement process used in the updated standard has reduced significantly the complexity of verification procedures increasing the accuracy of measurements.

Algorithms of exact restoration in an analytical form of dynamic characteristics of non-stationary dynamic systems are constructed. Non-stationary continuous dynamical systems modeled by Volterra integral equations of the first kind and nonstationary discrete dynamical systems modeled by discrete analogues of Volterra integral equations of the first kind are considered. The article consists of an introduction and three sections: 1) The exact restoration of the dynamic characteristics of continuous systems, 2) The restoration of the transition characteristics of discrete systems, 3) Conclusions. The introduction provides a statement of the problem and provides an overview of dynamical systems for which algorithms for exact reconstruction in an analytical form of the impulse response (in the case of continuous systems) and the transition characteristic (in the case of discrete systems) are constructed. In the first section, the algorithm is constructed for the exact reconstruction of the impulse response of an non-stationary continuous dynamic system from three interconnected input signals. The first signal may be arbitrary, the second and third signals are associated with the first signal by integral operator. The exact formula for the Laplace transform of the impulse response, represented by an algebraic expression from the Laplace transform of the system output signals, is given. A model example illustrating the effectiveness of the algorithm is given. The practical application of the presented algorithm is discussed. In the second section, an algorithm is constructed for the exact reconstruction of the transition response of a nonstationary discrete dynamical system from three input signals that are interconnected. The first signal may be arbitrary, the second and third signals are associated with the first summing operator. The exact formula of the Z-transform of the transition characteristic is presented, which is represented by an algebraic expression from the Z-transform of the system output signals. A model example is given. The “Conclusions” section provides a summary of the results presented in the article and describes the dynamic systems to which the proposed algorithms can be extended.

When constructing inertial/GNSS navigation systems, it is necessary to determine coordinates of a GNSS antenna relative to an inertial measurement unit. It is proposed to solve this problem by integrating of the inertial unit and GNSS antenna’s element into a common structure called an integrated antenna. This approach allows to determine the required coordinates in factory conditions, during a manufacturing of the integrated antenna. Operation principles of design modules of the integrated antenna and ways to use this antenna in the inertial/GNSS navigation systems have been described. Design features of a half-duplex digital data exchange between the antenna and a data processor have been indicated. Approaches to use this exchange to solve some service tasks of the navigation system have been proposed. It is noted that the integrated antenna has its own measuring basis. Methods of accounting of the attitude of this basis in practical applications of the integrated antennas in the single- and multi-antenna inertial/GNSS navigation systems have been described.

One of the most important tasks in the metrological support of time and frequency measurements is a development of an extremely stable narrow-bandwidth laser sources and oscillators of the sets of the equidistant narrow optical spectral lines (the socalled “optical combs”). These devices are necessary for the transmission of the reference frequency signals and for use as part of mobile sources of time and frequency reference signals in optical and microwave spectral ranges. They are also required for precision ultra-high resolution spectroscopy. A promising direction for the creation of highly stable narrow-band lasers and optical combs is the use of miniature optical whispering gallery modes resonators. Recently, research has been actively performed on the properties and manufacturing techniques of such resonators, as well as devices using them. The article provides a review of current research into applications of optical whispering gallery mode resonators in time and frequency metrology. Main advantages and disadvantages of such devices and prospects for their further use are discussed. The authors review in detail some examples of existing laboratory setups of Russian and foreign scientific c groups.

Work is devoted to studying of a linear mode thermodynamic – a mode which is actively investigated now. One of the main concepts of a linear mode – local entropy rate of production. The purpose of given article consists in expansion of a circle of problems for which it is possible to calculate a local entropy rate of production, namely its definition, using the experimental “time-temperature” curves of heating/cooling. “Time-temperature” curves heating or cooling are widely used in non-stationary thermophysical experiments at studying properties of substances and materials: phase transitions of the first and second sort, a thermal capacity, thermal diffusivity. The quantitative substantiation of the formula for calculation of the local entropy rate of production in which it is used thermogram (change of temperature from time) which is received by a method of pulse electric heating is resulted. Initial time dependences of electric capacity and temperature are measured on the sample of niobium in a microsecond range simultaneously. Conformity of two dependences of the local entropy rate of production from time is shown: one is calculated under the known formula in which the brought electric capacity is used; another is calculated, using the thermogram.

The analysis of a new class of measuring instrument for heat quantities based on the use of multi-valued measures of heat conductivity of solids. For example, measuring thermal conductivity of solids shown the fallacy of the proposed approach and the illegality of the use of the principle of ambiguity to intensive thermal quantities. As a proof of the error of the approach, the relations for the thermal conductivities of the component elements of a heat pump that implements a multi-valued measure of thermal conductivity are given, and the limiting cases are considered. In two ways, it is established that the thermal conductivity of the specified measure does not depend on the value of the supplied heat flow. It is shown that the declared accuracy of the thermal conductivity measurement method does not correspond to the actual achievable accuracy values and the standard for the unit of surface heat flux density GET 172-2016. The estimation of the currently achievable accuracy of measuring the thermal conductivity of solids is given. The directions of further research and possible solutions to the problem are given.

The problem of interfrequency signal delays estimation of GLONASS system navigation satellite is considered Such delays in the radio-frequency massage of navigation satellites are the source of the instrumental error of pseudorange measurements. The estimation method of interfrequency signal delays is proposed, based on the calculation of first differences of pseudorange measurements on navigation satellites, the relative position of which diff ers by no more than 1°. The experiment on estimation of inter-frequency delays signal on the basis of the developed method was conducted. The experiment is based on the use of calibrated navigation receiver to separate errors caused by signal delays in the receiver and navigation satellite. Also, to minimize the effects of the Earth's ionosphere layer navigation signal delay, only those measurements taken at a low Total Electronic Concentration TEC are included in the processing. Pseudorange measurements using GLONASS and GPS navigation satellites signals were used as the main source data. The results of the estimation for all GLONASS orbital group satellites were compared with the form values provided in the navigation massage. The results of experimental research have been analyzed and the values of standard deviation of GLONASS orbital group delays have been obtained. To confirm the adequacy of the results was checked for internal convergence of the results and determined the error of the developed method for assessing the interfrequency delays of navigation spacecraft.

One of the conditions for ensuring the safety of air transport operation is the quality of aviation fuel refueled in aircraft. Fuel quality control is a multi-parameter task that includes monitoring the free moisture content. Regulatory documents establish the content of free water no more than 0.0015% by weight. It is developed a direct electrometric microwave resonance method for controlling free moisture in aviation fuels, which consists in changing the shape of the water drops by pressing them on a solid surface inside a cylindrical cavity resonator. This can dramatically increase dielectric losses. Analytical and experimental analysis of the proposed method is carried out. The control range from 0,5 to 30 μl of absolute volume of moisture in aviation fuels with a maximum error of not morethan 25 % is justified The sensitivity of the proposed method for monitoring microwave losses in free moisture drops transformed into a thin layer by pressing is an order of magnitude greater than the sensitivity of the method for monitoring microwave losses in moisture drops on a solid surface in a resonator. The proposed method can be used as a basis for the development of devices for monitoring the free moisture of aviation fuels in the conditions of the airfield and laboratory. The direction of development of the method is shown.

The article presents the results of checking mathematical model of the created decreasing pressure effusion computer gas density analyzer. Operating principle of a decreasing pressure effusion gas density analyzers is based on measuring the outflow time of the analyzed gas certain volume through a microdiaphragm. A generalized scheme of such analyzers and their operation are described in article. Initial equations of the mathematical model, the assumptions and the results of the development of the mathematical model are presented. The created experimental setup for testing the developed mathematical model and its operation also are described. The mathematical model was tested in the course of numerous experiments on this facility for a number of gases. Studies have also been performed to assess the effect of temperature on the measurement result. The results of the mathematical model test are presented in the article. The results of experimental studies were compared with the calculated data obtained on the basis of a mathematical model. As a result, the error of the mathematical model of the decreasing pressure effusion gas density analyzers was determined and conclusions were made about its adequacy and possible further use for designing and calculating decreasing pressure effusion gas density analyzers.

The article raises the problem of ensuring metrological traceability of the measurement results of indicators of quality and nutritional value for food products and food raw materials: water (moisture), nitrogen (protein, crude protein), fat, ash and carbohydrates. The problem under consideration can be solved by applying reference materials of food composition, traceable to state primary measurement standards GET 173-2017 and GET 176-2019 and primary reference measurement procedures (PRMP), for attestation of measurement procedures and accuracy checking of measurement results. The article discusses the results of the PRMP development of mass fraction of fat, ash and carbohydrates in food products and food raw materials, as well as mass fraction of crude fat (oil content) in oil crops seeds and products based on them. The paper also presents metrological characteristics of reference materials of composition of dry dairy products, grain-milk dry porridges for nutrition of babies, grain dry porridges for nutrition of babies, egg powder, freeze-dried meat products, animal feed. The results of the work allow for building a chain of metrological traceability from GET 173-2017, GET 176-2019 and PRMP to routine measurement procedures, thereby ensuring the uniformity of measurements of nutritional value of food products.