On-board Equipment Research Articles

Features of generation and propagation of the extremely low frequency waves excited in the ionosphere under the powerful HF radioemission influence

The experimental results of the extremely low frequency emission characteristics excited in the outer ionosphere under the ionospheric plasma heating by high-latitude EISCAT facility are presented. The experiments have been conducted in the period of 20062010 yr. using two main schemes of extremely low frequency generation including the impact of the heating facility amplitude modulated emission and two unmodulated pump waves with the frequency detuning. In-situ measurements of the plasma wave disturbances were performed at the outer ionosphere heights using on-board equipment of DEMETER microsatellite. In work the spatial, amplitude and spectral characteristics of the generated extremely low frequency emissions are determined. It is shown that the characteristic size of the extremely low frequency emission is about 400600 km along the trajectory of the DEMETER microsatellite. The registration area spatial position is determined by both the applied generation scheme and the background plasma density distribution. The extremely low frequency emission electric field strength at the Earths outer ionosphere heights is 50330 V/m.

Software tool for evaluation of reliability and survivability of complex technical system based on logical-probabilistic methodology

The paper presents solutions for estimation and analysis of complex system (CS) reliability and survivability indicators based on the logical-probabilistic approach. Modified logical-probabilistic method and software tool for evaluating the reliability and survivability of onboard equipment (OE) of small satellites were developed (SS). The correctness of the suggested method and software tool was shown by computational experiments on some systems of CS SS similar to Belarusian SS, and later compared with the “Arbitr” software complex results.

Анализ воздействия разряда молнии на ракетоносители космического назначения

The impact of a direct lightning discharge on a space rocket is analyzed. Mechanical, thermal, and electromagnetic impacts are considered in the entire range of possible lightning current intensities. It is noted that the lightning main characteristic that determines various physical factors of its impact on objects is the lightning discharge current intensity as a function of time. Thermal factors are caused by rapid heat release when the lightning channel comes in direct contact with the rocket external structural components. The energy released in the lightning channel is determined by the transferred charge, flash duration, and lightning current amplitude. In most cases, this energy is sufficient to ignite fuel mixtures and gases produced during refueling. It is shown that at a current of higher than 100 kA, there is a danger of melting the rocket external structural components. The mechanical impact caused by an acoustic shock wave does not pose a hazard even at a current of 200 kA. Electrodynamic impact can cause flattening of hollow metal tubes. Electrical factors are associated with the impact of lightning current and overvoltages occurring in the onboard equipment. Electromagnetic impact is always dangerous when lightning hits a rocket and requires protective measures for the onboard equipment and cable network.

ОСОБЛИВОСТІ КЛАСИФІКАЦІЇ ТА МЕТОДІВ ВИБОРУ БПЛА

Unmanned aerialvehicles (UAVs) are being actively adopted in various areas of human activity, demonstrating excellent results. Their usage allows to minimize the risks of people being in high-risk conditions, and integration with various systems expands the range of functions that previously seemed impossible.There are currently over 1,500 different official UAV designs, and the number is growing rapidly. The effectiveness of choosing a specific model and its subsequent application for the specific tasks requires a clear classification. Domestic classification is mainly inherent in the military sphere and in the sphere of civil protection with a limited extent, which creates uncertainty for other possible spheres of application. Other classifications do not have sufficient completeness and do not consider an integrated approach to modern requirements and technical characteristics of UAVs.Currently there is no single science-based systematic approach to the design of UAVs based on the use of optimization methods. It is clear that the problem of this kind is multi-criteria, and cannot do without optimization mathematical models and methods. However, the dynamics of the development of elements and solutions, the growth of information objects regarding new models and characteristics, the consideration of interrelated factors make this process impossible without decision support systems. The use of parametric synthesis allows to determine the compromise between stability and workability of systems.Criteria analyze for classification and modern methods for selecting unmanned aerial vehicles.The usage of electronic software tools, so-called electronic drone calculators, can help to solve the problem of choosing the optimal UAV design.Most of the classifications today are oriented to the needs of the military. The main criterion for choosing a scheme depends on the list of expected functions and tasks, flight range and altitude, as well as requirements for cargo capacity and possible on-board equipment. The approach of the mathematical method of multi-criteria evaluation, such as the method of analyzing hierarchies, is optimal.The article is an overview and information.

Обеспечение радиационной стойкости бортовой аппаратуры командных радиолиний при длительных сроках активного существования космических аппаратов (Часть 1)

The experience of JSC “Russian Space Systems” in the development of on-board equipment for command radio links of spacecraft for various purposes with a given level of radiation resistance under conditions of long-term exposure to ionizing radiation of outer space for the period from 2003 to 2021 is summarized. The main stages of work to ensure the resistance of onboard equipment to integral dose effects and the effects of single events are considered. Methodological and software resources have been developed that allow correct prediction of local dose loads of ionizing radiation from outer space in the on-board equipment of command radio links, taking into account the effect of “dose amplification” of secondary bremsstrahlung. The methodological issues of ensuring the terms of the active existence of the onboard equipment are considered, using the cold redundancy of critical devices and components. The use of cold redundancy makes it possible to increase the duration of active existence relative to resistance to integral dose effects by about 1.5 times. The effectiveness of the developed methodological and software resources for confirming the radiation resistance of the onboard equipment of command radio links is proved by successful operation of about 100 spacecraft for various purposes in the 2005–2021 period.

An Improved On-Orbit Relative Radiometric Calibration Method for Agile High-Resolution Optical Remote-Sensing Satellites With Sensor Geometric Distortion

Noticeable striping artifacts in collected satellite imagery, caused by the inconsistency of pushbroom sensor detector responses, degrade the image quality. Relative radiometric calibration aims to calibrate inconsistencies in terms of detector responses, thereby eliminating detector-level striping artifacts. Yaw calibration has become the preferred imagery-based calibration method for satellites without on-board calibration equipment, owing to its high accuracy and convenience. However, it often relies on a large uniform field on the Earth’s surface and is a linear calibration method. This method does not consider acquisition-related geometric errors associated with the sensor, resulting in reduced calibration accuracy. In this study, we propose an improved method for yaw calibration, which accounts for the geometric distortion of sensor imaging and does not require a uniform field. A fast geometric-positioning algorithm was used to remove geometric distortion, followed by high-precision extraction of the calibration reference for each sensor’s detector. The dynamic range of the sensor calibration was extended, followed by the calibration of the sensor nonlinear response model. Our results based on Yaogan-25 images suggest the following: 1) the improved method effectively eliminates the “sawtooth” caused by the yaw calibration method without considering the geometric distortion and 2) it outperforms other imagery-based calibration methods with respect to visual destriping effects such that the root-mean-square deviations of the corrected imagery experienced a decrease of 0.65 percentage point, compared with that of the statistical method, and 0.17 percentage point for the yaw calibration. Such improvements will promote high-quality applications of remote-sensing images.

Effects of Oxidative Deterioration of Lubricating Oil on Tribological Characteristics of Aluminum Bronze Porous Materials

In recent years, there has been a demand for technology for achieving carbon neutrality. To meet this demand, technologies such as reduction of production energy, weight reduction of raw materials, and recycling have been studied for vehicle on-board electrical equipment. Aluminum bronze, which is one of the metal materials with low melting point and low density, has the properties that facilitate achievement of carbon neutrality. In this study, a porous aluminum bronze material was used for sliding parts, and a pin-on-disk friction test and a chemical analysis were conducted with the sliding material oxidized in a high temperature atmosphere. The effect of the exposure time of the sliding material on the tribological (friction) characteristics was experimentally investigated. The results showed that the viscosity of the lubricating oil impregnated in the porous aluminum bronze material was significantly changed with the exposure time, affecting the friction characteristics. Moreover, the oxidation product of this lubricating oil was adsorbed on the surface of the sliding part material, and resulted in a marked change of the friction characteristics.

Fault diagnosis for on-board equipment of train control system based on CNN and PSO-SVM hybrid model

Fault diagnosis for on-board equipment of train control system based on CNN and PSO-SVM hybrid model

Constructs of the onboard equipment ensuring heatsink and heat distribution under the space vacuum conditions

Constructs of the onboard equipment ensuring heatsink and heat distribution under the space vacuum conditions

МИКРОПРОЦЕССОРНАЯ СИСТЕМА АВТОМАТИЧЕСКОГО УПРАВЛЕНИЯ СРЕДСТВАМИ ПРОТИВОПОЖАРНОЙ ЗАЩИТЫ САМОЛЕТА

Relevance The ever-increasing requirements for the safety of the use of aviation technology are inextricably linked with the problem of providing fire protection for aircraft, both military and civilian. The complexity of the problem of ensuring the fire safety of flights is associated with an increase in the intensity of the use of aviation equipment and the expansion of the range of functional tasks performed by it. The resulting complication of on-board equipment and an increase in the number of energy-intensive devices creates the prerequisites for the occurrence of fires on board the aircraft. At the same time, the remoteness of places where fires are possible, the variety of causes leading to fires, as well as the ambiguity of the conditions for the onset and spread, increase the likelihood of equipment failures, but also complicate the crew's activities. The purpose of the study is to implement a prospective aircraft fire protection system that will increase the effectiveness of existing fire extinguishing equipment. The relevance of this research project lies in the creation of an aircraft fire-fighting system that will provide timely detection of overheating/fire in the nacelles of the main power unit, in the compartments of the auxiliary power unit, baggage and cargo compartments and aircraft toilets; reliability of information from fire detection and elimination systems; increase the effectiveness of existing firefighting equipment. Aim of research The aim of the study is to develop a future aircraft fire protection system that will increase the effectiveness of existing fire extinguishing equipment. The objectives of the research project are: 1. Choosing a hardware complex for electronic indication and signaling of the aircraft fire-fighting system; 2. Integration of the fire protection complex into the general aircraft equipment control system. Research methods Analysis of modern high-performance aircraft fire protection systems and creation of a promising fire protection system based on the data obtained Results In the course of this research project, a hardware complex for electronic indication and signaling of the aircraft fire system was selected, and the integration of the fire protection complex into the control system of general aircraft equipment was carried out.

Using naturalistic driving data to identify driving style based on longitudinal driving operation conditions

Purpose An individual’s driving style significantly affects overall traffic safety. However, driving style is difficult to identify due to temporal and spatial differences and scene heterogeneity of driving behavior data. As such, the study of real-time driving-style identification methods is of great significance for formulating personalized driving strategies, improving traffic safety and reducing fuel consumption. This study aims to establish a driving style recognition framework based on longitudinal driving operation conditions (DOCs) using a machine learning model and natural driving data collected by a vehicle equipped with an advanced driving assistance system (ADAS). Design/methodology/approach Specifically, a driving style recognition framework based on longitudinal DOCs was established. To train the model, a real-world driving experiment was conducted. First, the driving styles of 44 drivers were preliminarily identified through natural driving data and video data; drivers were categorized through a subjective evaluation as conservative, moderate or aggressive. Then, based on the ADAS driving data, a criterion for extracting longitudinal DOCs was developed. Third, taking the ADAS data from 47 Kms of the two test expressways as the research object, six DOCs were calibrated and the characteristic data sets of the different DOCs were extracted and constructed. Finally, four machine learning classification (MLC) models were used to classify and predict driving style based on the natural driving data. Findings The results showed that six longitudinal DOCs were calibrated according to the proposed calibration criterion. Cautious drivers undertook the largest proportion of the free cruise condition (FCC), while aggressive drivers primarily undertook the FCC, following steady condition and relative approximation condition. Compared with cautious and moderate drivers, aggressive drivers adopted a smaller time headway (THW) and distance headway (DHW). THW, time-to-collision (TTC) and DHW showed highly significant differences in driving style identification, while longitudinal acceleration (LA) showed no significant difference in driving style identification. Speed and TTC showed no significant difference between moderate and aggressive drivers. In consideration of the cross-validation results and model prediction results, the overall hierarchical prediction performance ranking of the four studied machine learning models under the current sample data set was extreme gradient boosting > multi-layer perceptron > logistic regression > support vector machine. Originality/value The contribution of this research is to propose a criterion and solution for using longitudinal driving behavior data to label longitudinal DOCs and rapidly identify driving styles based on those DOCs and MLC models. This study provides a reference for real-time online driving style identification in vehicles equipped with onboard data acquisition equipment, such as ADAS.

Калибровка бортовой аппаратуры измерения псевдодальности между космическими аппаратами для повышения точности определения расхождения их шкал времени

Technologies for range-finding measurements between spacecraft are increasingly used in achieving the targets of modern spacecraft. The stability of the systematic error is one of the main factors affecting the accuracy of achieving a target. This determines the requirement to ensure the stability of the systematic error at the level of several centimeters in the presence of destabilizing factors and a tendency to increase the spacecrafts active life in orbit. Apart from searching for methods implemented directly in the onboard equipment, it is advisable to consider mathematical methods that are applicable at the stage of processing measurements when achieving the spacecraft targets. The paper describes the technology for determining and accounting for calibration corrections for spacecraft onboard radio-technical equipment intended for range-finding measurements and exchanging information between spacecraft. This technology is based on statistical processing of residuals of linear combinations of measured parameters relative to their high-precision calculated analogs, obtained using a posteriori ephemeris-time information. The use of this technology makes it possible to compensate for the change in the constant component of the systematic measurement error at the stage of spacecraft operation in orbit.

Анализ технологичности деталей гибких волноводных секций космического аппарата

Satellite onboard equipment includes waveguide transmission lines. One of the tasks to be solved is the temperature decoupling of the waveguide path and onboard equipment devices. In order to prevent waveguide path deformation during expansion/contraction due to thermal effects, the waveguide is equipped with a flexible waveguide section capable of changing the length without deteriorating radio technical characteristics. The paper considers the issues of fabrication of flexible waveguide parts, concerning the requirements for structure, properties, heat treatment of raw materials, dimensions of workpieces, equipment, and tooling. Within the study, we optimized and tested in practice operations of the technological process of extracting parts from sheet material, rolling, profiling, and shaping, which make it possible to manufacture parts of waveguide paths of the required quality.

Investigation of the Two-Mode Regime of Two-Gap Photonic-Crystal Resonance Systems Produced on a Printed Circuit Board with Fractal Elements "Minkowski Island

Introduction. The development of new amplifiers and generators of the Ku- and K-bands (12…27 GHz) for use in onboard equipment is increasingly attracting research interest. Low-voltage multi-beam klystrons (LMBK) can be a promising element base for such devices. Serious problems are associated with the need to suppress parasitic modes of oscillations in NMLK operating in the centimeter and millimeter range. A possible solution is to use double-gap photonic-crystal resonators (DPCR) in LMBK. Another promising direction for improving the characteristics of such resonators is to use resonant segments of strip lines with fractal elements. In this case, the strip lines are placed on a dielectric substrate in the interaction space. Such resonators exhibit new properties that are useful for klystrons (an increase in characteristic impedance, suppression of the spectrum of unwanted frequencies, a reduction in mass and dimensions).Aim. Determination of an optimal set of electrodynamic and electronic parameters of double-gap photonic-crystal resonance systems with fractal elements "Minkowski Island" when operated as part of the LMBK resonator system, excited on π- and 2π-modes of oscillation.Materials and methods. To calculate the electrodynamic parameters of resonators, the method of finite differences in the time domain was used. The well-known Wessel-Berg method was used to calculate electronic parameters, such as the Ge / G0 electronic conductivity and the coupling coefficient M.Results. The main electrodynamic parameters of the resonator – Q-factor, resonant frequency and characteristic impedance – were investigated. The electronic parameters of the resonator, the coefficient of coupling with the electron beam, and the relative electronic conductivity for π- and 2π-modes of oscillations were calculated. In this case, three variants of the resonator with zero, first and second iterations of the fractal element were investigated. The amplitude-frequency characteristics of the resonator were investigated with a change in the pitch of the photonic crystal lattice. An estimation of the inhomogeneity of the high-frequency field in the interaction spaces of the resonator was carried out. Operational conditions were determined simultaneously for two types of oscillations without self-excitation.Conclusion. The results can find application in the development of resonator systems for klystron-type devices in the centimeter and millimeter ranges.

НАВЧАЛЬНО-ТРЕНУВАЛЬНА СИСТЕМА ДЛЯ ПІДГОТОВКИ ОПЕРАТОРІВ БЕЗПІЛОТНИХ АВІАЦІЙНИХ КОМПЛЕКСІВ

In order to meet the needs of the Armed Forces of Ukraine (AFU) for specialists in the operation of unmanned aerial systems, the Zhitomir Military Institute named by S. P. Korolev deployed training for operators - military pilots. While creating the material and technical base, the issue of developing and introducing into the training process of simulators that would meet the requirements of higher military education training. Development of the scientific training system was carried out on the basis of the list of basic training issues, profound mastery of which is mandatory for the UAV operator’s. The training system was developed, manufactured and implemented in the training process, which is built as a schematic-abstracted one to ensure the conditions of effective learning material assimilation. The content basis of the scientific training system is a flat schematic outline of the aircraft, which contains typical onboard equipment of unmanned aerial vehicles and a reconstructed connection scheme of the elements. The power of the onboard equipment is provided from the classroom power supply via a stabilized power supply unit. Operation of the onboard equipment can be controlled from the manual control panel and from the ground control station via the Mission Planner program. The Mission Planner can also be controlled from the X - Plane flight simulator. In flight simulation mode, the Mission Planner screen displays a map of the flight route, the X-Plane screen displays the view and spatial orientation as well as the corresponding servo drives of the aircraft's steering surfaces and the main engine operation modes. The software of the scientific training system allows planning and adjusting the route and flight program, practicing UAV piloting skills in the flight simulator mode, simulating flight in different weather conditions. The scientific training system includes a two-channel hardware-software oscilloscope which allows to research electric processes in different electric lines of airborne equipment of the aircraft and pair interconnections between them. Functional properties of scientific training system allow to study theoretically and practice practically a wide range of training issues required in training of UAV operators. Up to this circle includes both the issues necessary for mastering drone piloting and the issues necessary for mastering the maintenance and repairs of UAV.

An Approach for Modeling and Performance Analysis of Three-Leg Landing Gear Mechanisms Based on the Virtual Equivalent Parallel Mechanism

In order to realize the safe taking-off and landing of aircrafts on unstructured terrains, the landing gear on the aircraft is required to have a terrain-adaptive function. As a kind of aircraft onboard equipment, adaptive landing gear puts forward higher requirements for its design. This article proposes a virtual equivalent parallel mechanism (VEPM) modeling and performance analysis approach for the landing gear mechanism with three kinematic branch chains. In this approach, the unstructured terrain data were mapped to a moving platform. The moving platform, virtual restrained chains and the original mechanism of the landing gear mechanism combines the VEPM. In this way, the performance analysis object of the landing gear can be converted from a single kinematic branch to the entire system. The new approach can more effectively evaluate the overall motion performance and stability performance of the landing gear, and can help improve the structural design and control algorithm design of the spacecraft landing gear.

Dynamical Effect Investigations of Component’s Internal Interface by Using Techniques of Rigid-Flex Coupling Simulation

As a component of servicing car body, the internal interfaces of aluminum alloy carbody include all connections of equipments hanged under floor and mounted on roof, which are expected to form the weak coupling relationship. For an imported prototype with primary hunting phenomenon, a dynamical design methodology of speeding-up bogies was proposed. The analysis graph of full-vehicle stability properties and variation patterns is used to clarify a self-adaptive improvement direction, i.e., λeN ≥ λemin, and λemin = (0.03–0.05). Therefore, the central hollow tread wear can be self-cleaned in time or regularly by crossing over the dedicated lines of different speed-grades. The modified strategy with strong/weak internal interface transaction of servicing car body was furthermore formulated based on the dynamical condensation method of component interface displacements. The causal relationship between bogie vibration alarm and car body fluttering phenomenon was then demonstrated by using techniques of rigid-flex coupling simulation. The self-excited vibration of traction converter intersects with the unstable hunting oscillation, ca. 9.2/9.3 Hz, which is consistent with the conclusions of tracking-test investigations on two car body fluttering formations. The technical space to promote the construction speed is thereby lost completely because of ride comfort decline, unsafe vibration of onboard electrical equipments, and weld fatigue damage of aluminum alloy car body. However, the rigid-flex coupling simulation analyses of trailer TC02/07 confirm that the safety threshold of bogie vibration warning can be appropriately increased as long as the lateral modal frequency of traction converters is greater than 12 Hz, preferably close to 14 Hz.

VIBRATION PROTECTION OF ON-BOARD ELECTRONIC EQUIPMENT FROM EXTERNAL INFLUENCES

The article is devoted to the problems of protection of on-board electronic equipment (BEA) from vibration effects. To ensure BEA protection, it is necessary to know the characteristics and conditions of external influences and, in accordance with this, choose a method to reduce their influence on the BEA performance. The article discusses the most common ways to reduce the impact of mechanical external influences, and also provides analytical calculations of the printed circuit board and their correlation with the results of mathematical modeling. The developed technique for modeling vibration effects on the printed circuit assembly allows you to more effectively evaluate the physical characteristics of the product, thereby avoiding design errors and inaccuracies.

Mathematical Modeling and Optimization Heat Pipe Systems

The results of optimization of the supporting structure of a block of onboard electronic equipment with a built-in single flat heat pipe in the supporting structure with an integrated heat pipe system are presented, using the example of solving a model problem with a single heat source. The comparison was carried out at an equal temperature, occupied volume and for a certain maximum temperature of electrical radio products. The results of computational modeling are presented, demonstrating a comparison of the characteristics of a single flat heat pipe with a system of sequentially located flat heat pipes. Ultimately, the studies carried out have determined the limiting values of the removed thermal power of a single heat pipe, two-level and three-level heat pipe systems with different heat carriers. The versatility of the mathematical model, supplemented by the optimization method, has been confirmed

Synthesis method of orthogonal encoding and decoding matrices based on integers, providing the implementation of code division of channels

The method of code division of binary channels based on the arithmetic analogue of convolutional codes is investigated. The synthesis method of encoding and decoding matrices is proposed for implementing a code division of channels regardless of the number of users. The synthesis and implementation of theses pairs of matrices will significantly simplify the schemes for constructing encoding and decoding devices. Research results can be used in various communication technologies: in real-time systems, in distributed systems in on-board equipment complexes, to ensure reliable information transfer.