Congratulations to BNTU on its anniversary from the editor-in-chief of the magazine, O.K. Gusev.

Miniaturization and increased accuracy of orientation and navigation systems for controlling mobile objects are a pressing task for the aviation, space, transport, and oil and gas industries. A promising solution to this problem is the application of wave solid-state gyroscopes (WSG), which detect object rotations by utilizing the phenomenon of standing wave inertia, excited in ring or bulk resonators. It is shown that WSGs can have various resonator configurations (ring, cylindrical, conical, hemispherical) and be made of various structural materials. Examples of ring silicon resonators are given. It is shown that WSG resonators made of metal alloys (ring, cylindrical or conical) allow creating sensors of the middle accuracy class. Navigationclass WSG are implemented on the basis of quartz cylindrical or hemispherical resonators, the time constant of which can reach up to 1000 s or more. It is shown that on the basis of WSG it is possible to create two types of sensors: angular displacement meters and angular velocity sensors. The mathematical model of the WSG, identical to the equations of the classical Foucault pendulum, is presented. It is applicable for describing sensors of both types. The efficiency of using equations for the envelopes of oscillation amplitudes in describing the dynamic characteristics of the WSG is demonstrated. It is found that for the WSG of direct measurement, operating in the angular velocity sensor mode, an increase in the resonator quality factor increases its sensitivity to the angular velocity, but reduces the response time. Based on the vector diagram, the processes occurring in the WSG with the Coriolis acceleration compensation circuit are explained. A generalized mathematical model of the compensation-type WSG is presented, taking into account the processes of demodulation, modulation and the proportional-integral law of standing wave control. It is shown that the time constant of the compensation-type WSG is determined by the coefficient of the integral part of the controller.

Today, an expanding application of automatic systems demands research and development of novel types of sensors suitable for special conditions. Specifically, microelectromechanical pressure sensors are among of the most widely implemented devices. A pressure sensor comprises a silicon membrane that deforms under pressure of the medium and a measuring transducer that converts the deformation into electrical signal. The most promising and technologically advanced type of transducers for microelectromechanical pressure sensors are evanescent coupling-based transducers that implement light intensity passing through the gap between two optical waveguides varying under membrane deformation. Such scheme provides high sensitivity and extended dynamic range of the sensor. The paper is aimed at developing a design concept for the sensing element of a microelectromechanical pressure sensor with an evanescent coupling-based transducer. The technology for micro-optoelectromechanical sensor fabrication bases on a stepwise formation of the structures on two silicon on insulator wafers with their consequent bonding. The membrane is formed on the bottom wafer. The top wafer comprises stoppers. The waveguide structures are formed on both the wafers. We consider two methods of waveguide fabrication. First, they can be built up from silicon nitride by plasma-enhanced chemical vapor deposition. Second, they can be etched directly in the silicon wafer. The main characteristics of the pressure sensor are determined: losses, dependencies of the transmission coefficients on the length and width of the waveguides, gap, coupling length. The working range, where the optical transducer can measure membrane displacements proportional to the acting pressure reached 500 ± 80 nm for the silicon on insulator waveguide and 600 ± 80 nm for the Si3N4 waveguide. The optical transmission coefficient ranges from 0 to 0.86 for the silicon on insulator waveguide and from 0.09 to 0.53 for the Si3N4 waveguide. The main requirement to the membrane is assumed that its deformation does not exceed 80 nm.

For early detection of new operational nanosatellites and CubeSats, it is necessary to organize a network of stations for receiving signals and processing their parameters for preliminary orbit analysis. Aim of the work was to develop a ground station for receiving telemetry from nanoand picosatellites allowing measurements and rapid analysis of orbital parameters using precise timestamps. This station allows for measurements and express analysis of orbital parameters using precise time stamps. A prototype station was created based on the developed functional block diagrams for hardware and software of the telemetry receiving station. The prototype station allows for measurements of the reception time and packet duration, Doppler frequency shift, time delay, and express analysis of orbital parameters. The accumulated data were used to measure precise orbital parameters of nanoand picosatellites. A temporary binding was obtained using the GNSS module, allowing for setting of time stamps with an accuracy of no worse than 3 μs, which was sufficient for determining the inclination of a small spacecraft with an accuracy of no worse than 450 m. A method was shown for determining the orbital parameters of a small spacecraft by measuring Doppler frequency shifts tied to precise time of the GNSS receiver. The developed ground station for receiving and measuring the nanosatellites’s orbital parameters is located in Minsk and allows for receiving signals from satellites with an orbital altitude not exceeding 1000 km, with an orbital inclination of at least 40°, in the amateur radio frequency range of 430–440 MHz. Test radio engineering was conducted. Measurements and a method for conducting time synchronization were developed to improve the accuracy of determining the orbits of nanoand picosatellites.

In various areas of instrument engineering, it is necessary to register currents less than 10-12А or process signals from sensors whose internal resistance exceeds hundreds of megaohms. For these tasks, operational amplifiers with input junction field-effect transistors and an n-type channel (n-JFET) are predominantly used. However, there are a number of sensors whose output signal is a short current pulse, for the conversion of which into voltage, charge-sensitive amplifiers are used. The aim of the work was to develop a set of analog microcircuits with an input n-JFET on a master chip, ensuring the processing of signals from various high-resistance sensors. The article presents the electrical circuits of the developed operational amplifiers and charge-sensitive amplifiers, considers their design and circuit features, analyzes the results of circuit simulation, and formulates recommendations for selecting the operating mode of the charge-sensitive amplifier input n-JFET to minimize the rise time and noise level, taking into account operability in the temperature range. As a result of the work carried out, electrical circuits and layout were developed for the master chip of a set of microcircuits with an input n-JFET was created, including the NJAmp1 operational amplifier with parameters close to the AD8625, a low-power NJAmp2 operational amplifier for implementing a voltage follower similar to the AD8244, the NJAmp4 operational amplifier with an input current of less than 5·10-13 А, and a charge-sensitive amplifier allowing adjustment of the drain current of the input n-JFET. Connections of the developed devices according to a typical circuit of an instrumentation amplifier on three operational amplifiers make it possible to obtain a functional analogue of the AD8220 microcircuit.

Development of shooting electronic simulators (i.e. for hand weapons and without use ammunition) is an important task since the production of any type of small arms also requires the production of a simulator to instill aiming and shooting skills. Purpose of this work was to computationally optimize the ballistic trajectory modeling taking into account external conditions (temperature, pressure, wind) and with simplifications for various levels of the STrIzh family shooting simulators implementation. An analysis of the calculating external ballistics’ algorithms computational efficiency. This analysis was carried out in order to solve the "problem of bullet meeting" with an obstacle (local objects, targets or relief), taking into account all external factors for the developed family of publicly available shooting simulators "STrIzh" (including the initial, basic and virtual levels of implementation). When solving the "problem of meeting" a weapon ammunition of a weapon simulator with an element of a virtual target situation (relief, local object, target), a ballistic trajectory was calculated after each shot with a step of 0.5–1 m. In this case all types of ammunition, atmospheric factors (temperature, pressure, wind), angles of the target and course were taken into account. Synchronously with the evolution of the target situation, the problem of intersection of the ballistic trajectory with the surface of the shooting range, targets or local objects was solved. In addition to fixing the hit, a close miss and the time of shelling the target were recorded for subsequent assessment. To optimize the speed of the ballistic curve modeling process, its polynomial approximation was proposed in addition to the classical integration of differential equations. Studies on the error in representing the ballistic trajectory compared to the reference tables showed compliance with the requirements on the most important descending section of the trajectory within the accuracy of the above tables ± 5 cm, and on small sights ± 1.5 cm. Studies of various ballistics models’ algorithms performance revealed compliance with different levels of simulator implementation: initial, basic or virtual in terms of resource intensity. It was concluded that development of a family of electronic shooting simulators will be promising due to the improvement of computing tools and development of software libraries in order expanding the functionality of the simulators and reducing their cost and, therefore, increasing competitiveness.

Capacitance control of capacitive type micromechanical switches occurs at a high frequency due to a change of the distance between the flexible membrane and the reference electrode. Membrane oscillation will affect the electrical signals and operational characteristics of such switches. The aim of the work was to determine the values of vibrations of thin membranes under high-frequency exposure and compare them with the values of static bending under a similar constant force. The finite element analysis method was used with the recalculation of grid positions using the Euler–Lagrange method, with further modal and harmonic analysis of membrane vibrations under the action of a periodically varying ponderomotor force calculated for the selected voltage range. Gold and tungsten were considered as membrane materials. For considered membrane geometry the oscillation amplitude of the gold membrane in the studied preresonance frequency range is 16–21 % higher than the static bending value, whereas for the tungsten membrane it is only 2.2–3.2 %, which is explained by the significantly higher modulus of elasticity of tungsten. A more rigid membrane is also characterized by high values of natural frequencies. An increasing in the amplitude of the ponderomotor force leads to a multiple increasing of membrane vibration amplitudes, but does not change the shape of the amplitude-frequency response. The relevance of studying membrane vibrations in the preresonance values is shown. Constructive ways of increasing the rigidity of membranes and optimizing the design of MEMS systems with oscillation elements are given.

Automobile bridge and overpasses are essential elements of transport infrastructure in every country. Rapid diagnostics and subsequent monitoring of critical bridge and overpass components’ performance increases their service life. The aim of this study was to design a method and laser system for remote diagnostics of beam vibrations caused by dynamic loading and to apply them to a laboratory bridge model. The paper discusses a diagnostic method for bridge span vibrations based on laser-speckle correlation together with high-speed video recording. Using a laboratory model of a bridge, bearing structures under shock loading were studied by means of the proposed method. Relative surface displacements induced by different loading conditions were determined herein. The program for calculating correlation functions was optimized taking into account characteristics of the bridge span. In particular, surface displacements were analyzed with regard to the frame frequency and size of laser speckle patterns. Research technique was tested on the laboratory bridge model with beams made of different materials (steel, concrete, wood). For these beams, various shapes and amplitudes of displacements caused by shock loads are shown. Experiments demonstrate remote monitoring of bridge vibration under real shock loads caused by vehicle movement. This will be useful for further development of the proposed technique for bridge vibrations monitoring in real conditions.

Remote sensing data processing based on deep learning methods has been widely used in several cross-domain tasks. Current approaches predominantly focus on developing deep learning methods dedicated to object detection in densely populated urban environments, which are not well suited for sparsely distributed objects, especially fine-grained ones. A representative example is maritime vessel detection on open water surfaces. The challenges in this domain include heterogeneous noise backgrounds caused by varying lighting conditions, external artifacts, wave-induced blurs, top-view perspectives that yield poor feature maps of the objects, and the need to scan large areas for object searching. To address these challenges, this paper proposes a novel hybrid deep learning approach for sparse distributed fine-grained object detection. The proposed method includes an ensemble of classifiers based on DenseNet_l and ResNet_l, combined with a YOLOv11+ detector and a semi-supervised learning strategy. Furthermore, for fine-grained object detection, an improved version of the YOLOv11+fg model is proposed, featuring adapted C3K2, UpSample, and SPFF modules. The approach was developed, pretrained, and validated using the Airbus SPOT Satellite Imagery dataset, and further trained with a subset of ShipRSImageNet for fine-grained detection. Results demonstrate the effectiveness of large-scale scanning in remote sensing and recognize sparsely distributed objects, outperforming the fine-grained detection score compared to the original model.

When studying the process of moving a shot cloud in space, various devices can be used, for example, light screens. For such studies, it is advisable to have a simulation model of the set of optical sensor signals at the intersection of light screens with a shot cloud. Taking into account previous studies, in order to obtain such a model, it is necessary to know the time points of the beginning of the intersection of the shot cloud of light screens (in fact, the moments of the intersection of light screens with the fastest pellet). A technique is proposed that allows for given initial conditions (fraction size, initial velocity, etc.) to determine such moments for a set of light screens installed at specified ranges from the muzzle of the weapon. The essence of the proposed technique is that on the basis of solving a system of differential equations of external ballistics, a set of points is calculated corresponding to the dependence of the time when a fraction reaches a given range on the magnitude of this range. Next, the obtained dependencies are approximated by polynomials of the first, second and third degrees using the least squares method. The estimation of the approximation error by various polynomials for different types of cartridges is performed. An example of using the proposed technique to obtain the time points of the beginning of the intersection with a shot cloud for cartridges loaded with three different types of shot is given. In addition, the estimation of the error of the obtained dependencies in relation to the results of real experiments was performed. It is shown that at ranges up to 24 m, the relative error does not exceed 4 % for all types of cartridges. Based on the results obtained, specific recommendations for the practical use of the developed methodology are proposed. In the future, using the proposed technique, it is possible to create a simulation model of a set of optical sensor signals when a shot cloud crosses a set of light screens located at specified ranges from the muzzle of the weapon.

Screening studies play an important role in the prevention of chronic diseases of the cardiovascular system. One of the methods of screening vascular diagnostics is the method of photoplethysmography, which is widely used to assess the state of the cardiovascular system. To increase the efficiency of screening studies, it is proposed to use an algorithm for automated processing of photoplethysmograms, which is based on a relative description of the shape of the pulse curve, represented as a lattice function of the digital signal of the photoplethysmogram. The advantages of the relative description of the digital representation of a photoplethysmogram is its invariance to linear transformations of the signal amplitude and its time shift. This is important when analyzing pulse curves due to the possibility of changing the amplitude parameters of the curve, as well as their time shift during their registration. In this case, the analysis of changes in the shape of the photoplethysmogram is carried out after it is presented as a matrix of the ratio of the order of the components of the lattice function, representing the digital representation of the photoplethysmogram after the analog-to-digital conversion of the analog representation of the photoplethysmogram. During screening studies, changes in the shape of the photoplethysmogram are detected by comparing it with the standard of the ratio matrix. The ratio matrix is derived from the grid function of the digital representation of a typical photoplethysmogram of a patient. Such a photoplethysmogram characterizes a certain disease of the cardiovascular system. As a result of comparing the ratio matrices, the proximity of the features of the typical form of the photoplethysmogram to the photoplethysmogram standards is determined, after which the diagnosis of the disease is established. To implement the proposed research algorithm, a block diagram of an automated system for screening the cardiovascular system is provided. In this scheme, a homomorphic relative description is used to represent the photoplethysmogram digitally. This makes it possible to identify individual changes in the shape of the photoplethysmogram associated with abnormalities in the state of the cardiovascular system. This approach expands the arsenal of technical tools used in screening the cardiovascular system.

The increasing volume of measurement information makes manual processing impractical, while existing algorithms demonstrate limited effectiveness (up to 93 %). The aim of this work was to develop a combined algorithm based on a synthesis of existing methods to improve the accuracy and reliability of automated anomaly detection in data from industrial measurement systems, with a particular focus on processing images obtained by technical instruments. To enhance the accuracy and reliability of anomaly detection, a combined algorithm is proposed. It integrates statistical outlier detection methods based on a multivariate normal distribution for filtering noise anomalies, image binarization and morphological processing techniques for highlighting geometric contours, as well as a connected component analysis algorithm for localizing the region of interest. Special attention is paid to the processing of visualized data (images), where the key challenge is separating useful anomalies from noise. The developed method allows for the automatic extraction of regions of interest and compresses the source data by more than half without loss of informativeness. An approach for localizing several disparate regions with anomalous intensity based on connected component analysis has also been developed. The algorithm automatically assigns unique labels to each connected object and extracts their characteristics (area, perimeter, centroid) for subsequent analysis. Implementation and testing were carried out in the Wolfram Mathematica environment using the example of surface electrostatic potential distribution maps of composite materials. The proposed approaches simplify the subsequent analysis of measurement data and can be used in conjunction with machine learning algorithms.

Single-crystal silicon carbide is a promising third-generation semiconductor material. Thanks to its large band gap, electronics based on it can withstand extreme operating temperatures of up to 500 °C and above and are resistant to radiation. High-precision polishing of silicon carbide wafers improves the reliability of electronic components manufactured with it. This paper presents the results of magnetorheological finishing polishing of 4H and 6H polytype single-crystal silicon carbide, as well as reaction-sintered two-phase Si-SiC (6H and 15R) ceramics. An angstrom-level surface roughness was achieved (Ra = 1.6 Å for 4H-SiC and 2.2 Å for 6H-SiC single crystals), which is comparable to the Si–C bond length (≈ 1.9 Å) and is on par with the best results obtained by other state-of-the-art polishing techniques. After one hour of polishing, SiC single crystals with initial roughness values of 50 Å and 1030 Å reached the same final, and likely ultimate, Ra value of ≈ 2 Å. For the reaction-sintered ceramics, the Ra values were on the order of 10 Å, which is attributed to the height differential at the Si/SiC phase boundaries due to differences in their hardness and material removal rates during polishing.