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У статті проведено літературний огляд і досліджено існуючі методи визначення координат розташування джерела акустичного сигналу. Виокремлено переваги і недоліки наведених у статті пасивних і активних методів. Ці методи можуть знайти застосування в авіації, космонавтиці, машинобудуванні й інших галузях науки та техніки, де використовують вимірювання, і призначені для визначення координат джерела акустичного сигналу. Останнім часом спостерігається тенденція зростання інтересу до використання нейронних мереж для вирішення різних завдань і застосування їх у різних сферах. За допомогою штучних нейронних мереж можна опрацьовувати, аналізувати та узагальнювати інформацію. Авторами статті було порівняно метод визначення координат розташування джерела акустичного сигналу із застосуванням штучної нейронної мережі із вже існуючими методами. У цьому методі визначають наявність сигналу від джерела акустичного сигналу у точках прийому шляхом приймання і реєстрації сигналу у просторово рознесених точках з відомими координатами та подальшого визначення різниці часу поширення сигналів від джерела до точок прийому сигналу. Наявність сигналу визначають за серединою площі прийнятого сигналу. Кількість точок прийому сигналу встановлюють на етапі навчання штучної нейронної мережі за критерієм мінімуму похибки визначення координат джерела акустичного сигналу. Різниці часу поширення сигналів від джерела до точок прийому сигналу визначають між усіма точками прийому, які розташовані впорядковано або випадковим чином, причому ці різниці часу подають на вхід попередньо навченої штучної нейронної мережі, на виході якої отримують координати джерела акустичного сигналу. Застосування цього методу дозволяє визначати координати джерела акустичного сигналу, не маючи при цьому попередньої інформації щодо відстані до джерела акустичного сигналу або будь-яких інших характеристик об’єкта, визначати координати неперіодичних сигналів, спростити процес вимірювання часових інтервалів та обчислення координат. The article carries out a literature review and investigates the existing methods of determining the coordinates of the location of the acoustic signal source. The advantages and disadvantages of passive and active methods given in the article are highlighted. These methods can be used in aviation, cosmonautics, mechanical engineering and other fields of science and technology, where measurements are used, and are designed to determine the coordinates of the acoustic signal source. Recently, there has been a growing interest in using neural networks to solve various problems and their application in various fields. With the help of artificial neural networks, it is possible to process, analyze and summarize information. The authors of the article have compared the method of determining the coordinates of the location of the acoustic signal source using an artificial neural network with existing methods. In this method, the presence of a signal from the acoustic signal source at the reception points is determined by receiving and registering the signal at spatially separated points with known coordinates and further determining the difference in signal propagation times from the source to the signal reception points. The presence of a signal is determined by the middle of the area of the received signal. The number of signal reception points is set at the training stage of the artificial neural network according to the minimum error criterion in determining the coordinates of the acoustic signal source. The time differences of signal propagation from the source to the signal reception points are determined between all reception points, which are located in an orderly or random manner, and these time differences are fed to the input of a previously trained artificial neural network, at the output of which the coordinates of the acoustic signal source are obtained. The application of this method allows to determine the coordinates of the acoustic signal source without having prior information about the distance to the acoustic signal source or any other characteristics of the object, to determine the coordinates of non-periodic signals, to simplify the process of measuring time intervals and calculating coordinates.

El presente trabajo pretende experimentar y mejorar la metodología documental y prospectiva aplicada a la arqueológica subacuática mediante herramientas técnicas empleadas en el estudio de cuevas sumergidas. Para ello, se tiene como marco de referencia la denominada Cueva del Sistema Sa Gleda-Camp des Pou, en Mallorca. Los resultados obtenidos han demostrado que la combinación de los procedimientos prospectivos tradicionales, junto con una serie de técnicas novedosas como el sistema de mapeo por hilo MNEMO, la radiolocalización y radiogoniometría del dispositivo Pinger y el GPS subacuático ENC2 de Seacraft, junto a la topografía convencional de superficie, representan una solución precisa, segura y económicamente viable en lo que se refiere a la obtención de una georreferenciación rigurosa de estos contextos arqueológicos sumergidos, permitiendo definir estrategias prospectivas extrapolables al estudio de cavidades inundadas en condiciones similares. Además, este artículo defiende la hipótesis de que los antiguos poblados talayóticos mallorquines usaban estas cavidades como punto de abastecimiento de agua dulce para su supervivencia y uso cotidiano. Esto posibilita una reflexión sobre la evolución de los esquemas de racionalidad espacial de las comunidades prehistóricas en Mallorca y pone en valor la obtención de una documentación espacial detallada de estos puntos de aguada. The present work aims to experiment and improve the documentary and prospective methodology applied to underwater archaeology through technical tools used in the study of submerged caves. For this, the so called Cueva del Sistema Sa Gleda-Camp des Pou, in Mallorca, is used as a frame of reference. The results obtained have shown that the combination of traditional prospective procedures, together with a series of novel techniques such as the MNEMO wire mapping system, radiolocation and direction-finding of the Pinger device and Seacraft’s ENC2 underwater GPS, together with conventional topography surface, represent a precise, safe and economically viable solution in terms of obtaining a rigorous georeferencing of these submerged archaeological contexts, allowing the definition of prospective strategies that can be extrapolated to the study of flooded cavities under similar conditions. In addition, this article defends the hypothesis that the ancient Mallorcan Talayotic settlements used these cavities as a point of supply of fresh water for their survival and daily use. This makes it possible to reflect on the evolution of the spatial rationality schemes of the prehistoric communities in Mallorca and places value on obtaining detailed spatial documentation of these water supply points. Asociación Nacional de Arqueología Subacuática 0337SET2019ARQ.242-19.Alcudia Universidad de Cádiz PIN00111994

The article deals with the possibility of using signals of the Internet coverage, cell-phone networks, radio and television signals to provide detection of air targets. The advantages, disadvantages, composition and principle of operation of a semi-active radar system are considered in this article. Issues of technical realization of antennas and receivers of a semi-active radar system are investigated. An algorithm for signal processing in a semi-active radar system is proposed. For fulfilling the tasks of air surveillance and timely alerting of the air defense system to a higher degree of readiness when detecting the air threats and airborne intelligence assets of the enemy, currently in the area of the Operation of the Joint Forces the radar air surveillance system is deployed. This system is made up of traditional active radiolocation tools. The main disadvantage of such a system is its low survivability, which is due to the radiated signals, and, consequently, the ease of reconnaissance of radar positions by the enemy. Preservation of radar air surveillance system positions undetected and, consequently, the survivability of those radar systems is possible by supplementing them with the means of semi-active radar. Also, in the context of the so-called hybrid war in the area of Operation of the Joint Forces a ramified system of radio equipment continues to operate that can provide illumination field.

Location systems and their daily use in industry and individual users have become an inseparable part of our everyday functioning. However, often they are used in the so-called intelligent buildings. Unfortunately, just like location methods operating outside buildings are precise enough to determine our location (e.g. GPS systems for drivers), the situation of locating people inside the building is different, especially when such people cannot be equipped with additional devices (e.g. a transmitter signal). Nevertheless, it is essential in communication routes, large clusters of people, such as airports, railway stations or office spaces. At the same time, determine the number of people in space and the development of services that do not require direct contact (automatic patient/client registration) in times of a possible pandemic.

The paper presents the results of studies related to the possibility of cooperation of a LOFAR radio telescope with an external reference receiver in a passive radiolocation system in which the LOFAR radio telescope serves as a receiver. In particular, the problem of synchronization of signal registrations performed by LOFAR and the external reference receivers based on a Universal Software Radio Peripheral (USRP) device is considered. The field trials, whose results are presented in the paper, were one of the first stages of our research devoted to the practical verification of the capability of space target detection using the LOFAR station as a receiver in a passive radiolocation system.

The Ultra-High Frequency (UHF) band occupies a very vital region in the spectrum and is becoming very congested because many applications use it. The capsule camera (CapCam), an ultra-low power wireless device, is a Short Range Device (SRD) application that utilizes the UHF spectrum for medical endoscopy and it is designed to operate at the 430-440MHz frequency band range. This study will focus on the interference between the CapCam and other systems operating in the frequency of 435MHz and adjacent bands. Other systems that can operate in this band include non-specific SRD and radiolocation services such as airborne radar and ground radar stations. The Minimum Coupling Loss (MCL) method is implemented in this study. The findings showed that restricted distances between the CapCam and other services must be considered when the CapCam is in use. This should be done to avoid harmful interference from the CapCam especially in the case of radiolocation services.

The problem of radio imaging small aircrafts in radio systems with inverse aperture synthesis is considered. The Abstract - In order to identify and assess the dimensions of small aircrafts, including unmanned aerial vehicles, obtaining their images is based on a specific model of target movement. Creating a one-dimensional radio image of an aircraft on a straight segment of trajectory and a two-dimensional radio image of a rotating object is possible. The problem is reduced to a system of linear equations to be solved by the regularization method. The applied method is classified as a high resolution one. The proposed technique can be used in passive radio engineering systems for aircraft identification.

Small-scale irregularities of the ionosphere have a significant impact on the operation of various technological systems. In this paper, two independent methods are used to study them: radio illumination with satellite signals (the receiver is located at the Lomonosov Moscow State University) and radar (the DPS-4 ionosonde is located at IZMIRAN). To interpret the experimental data, a special program LocalDrift was developed to calculate the direction and speed of drift in a local area with small-scale irregularities. The data were obtained in the mid-latitude zone during September - December 2011 in quiet geomagnetic conditions. Comparison of the direction of the medium-scale irregularities drift and the orientation of the transverse anisotropy of small-scale irregularities in the F-region showed good agreement between these experimental data. The difference from the results of using the standard DriftExplorer program is shown.

The article reviews selected issues associated with the preparation, organization and execution of field training targeting the practical functional verification of passive sensors installed on-board various land, sea and air platforms. The APART-GAS trials combined the training of two NATO research task groups (RTG) operating within the SET Panel: SET-242 on passive radiolocation on mobile platforms (Passive Coherent Locators on Mobile Platforms) and SET-258 on multiband active and passive radars used in various military scenarios (DMPAR - Deployable Multiband Passive Active Radar Deployment and Assessment in Military Scenarios). The specificity of passive sensors, as well as the wide range of their applications resulted in numerous complications at the stage of developing and executing test scenarios conducted with the use of different aircraft types, including vertical launch rockets, water vessels and land vehicles. The article discusses successively the activities supporting the Warsaw University of Technology implemented by the Air Force Institute of Technology (AFIT). in the field of installing the sensors on individual platform, aircraft flight planning and their coordination in the course of the trials. AFIT performed the issues regarding the recording and imaging radiolocation data from the sensors participating in the trials and coupled within an Unclassified Radar Network (URN).

The paper presents the results of studies devoted to a new approach for suppression of Doppler-spread clutter occurring in a drone surveillance radar. The proposed approach is based on application of the technique using polynomial trend removal. This technique is characterized by relatively effective computational complexity, allowing for implementation in real-time radiolocation signal processing. The results of field experiments with a drone surveillance radar, presented also in the paper, confirmed the efficiency of the proposed method for the Doppler-spread clutter suppression as well as its computational effectiveness.

The most important trends of the development of communication and radiolocation systems are the application of higher frequencies and the transition to the use of complex signals for the creation of new advanced radio engineering systems with improved noise immunity. The search for new methods of improving the operation speed and «spectrum purity» of formed oscillations is very important. The purpose of the work is to extend functional capabilities of direct digital synthesizers and digital frequency synthesizers, when using them in radio-electronic systems of radiolocation, navigation and communication. Research methods. While solving the set tasks, the methods of the signal theory, number theory, probability theory and mathematical statistics as well as mathematical modeling, computer simulation and experimental research were used in the work. Results. These direct digital synthesizers allow synthesizing frequency-modulated and phase- manipulated signals and they have extended functional capabilities in comparison with other types of synthesizers. The given direct digital synthesizers can be used in adaptive communication systems, telecommunications, radio-engineering systems for the remote sensing of the ionosphere, in radiolocation and navigation systems.

In the paper, a new approach to the estimation of the localization of flying objects on the basis of multiple radiolocation sources has been proposed. The basic purpose of the radiolocation is the detection and tracking of objects. The main task of a tracking system is the estimation and prediction of localization and motion of tracked objects. In the classical tracking systems, the estimation of localization and motion of tracked objects is based on the series of measurements performed by a single radar. Measurements obtained from other sources are not taken directly into account. It is possible to assess the estimate of a tracking object on the basis of the different sources of information, applying, for example, least squares method (LSM). However, such solution is seldom applied in practice, because necessary formulas are rather complicated. In this paper, a new approach is proposed. The key idea of the proposed approach is so called matrix of precision. This approach makes possible tracking not only on the basis of radar signals, but also on the basis of bearings. It makes also possible the tracking of objects on the basis of multiple information sources. Simplicity is the main attribute of proposed estimators. Their iterative form corresponds well with the prediction-correction tracking model, commonly applied in radiolocation. In the paper numerical examples presenting advantages of the proposed approach are shown. The paper consists of seven parts. Introduction is the first one. In the second part the idea of the matrix of precision is presented and it is demonstrated how it can be used to uniformly describe the dispersion of measurement. Traditionally, the measurement dispersion is described by a matrix of covariance. Formally, the matrix of precision is an inverse of the matrix of covariance. However, these two ways of description are not interchangeable. If an error distribution is described by the singular matrix of precision then the corresponding matrix of covariance does not exist, more precisely, it contains infinite values. It means in practice that some components of a measured vector are not measurable, in other words, an error of measurement can be arbitrarily large. The application of the matrix of precision makes possible an uniform description of measurements taken from various sources of information, even if measurements come from different devices and measure different components. Zero precision corresponds to components which are not measured. In the third part, the problem of estimation of stationary parameters is formulated. Using the matrix of precision, the simple solution of the problem is presented. It appears that the

This study dealt with the performance analysis of time-of-arrival (TOA) techniques for mobile positioning in CDMA wireless cellular networks. Since several base stations are typically needed for mobile radiolocation, the problem of weak signal hearability at remote base stations is a major challenge, and a detailed analysis of this issue was presented by taking into account the near-far interference usually present in CDMA cellular networks. TOA-based positioning methods are well-suited for wide deployment of radiolocation services since the synchronization circuits that can extract timing information are readily available at the base stations receiving the mobile signal. For CDMA signals, the delaylocked loop (DLL) is commonly used as a TOA estimation device, and a detailed analysis of DLL-based TOA tracking was presented taking into account the cellular network layout, cell loading and other-user interference, as well as RF channel shadowing and pathloss that affect received signal strength at the different base stations. In particular, it was shown that the TOA tracking error statistics can vary considerably depending on the mobile link conditions with respect to the base stations involved in its positioning, and soft handoff (SHO) links with two or three base stations for mobiles close to border-cell regions were found to improve the precision of mobile TOA tracking. Using TOA information, a mobile radiolocation positioning algorithm based on a computationally-efficient, near-optimum approximate maximum likelihood (AML) processing was presented, and a generalization to the case of unequal timing error variances at the different base stations was also derived. Numerical results were presented to quantify

In this review, we present the main results on the creation of new information technologies based on textures, fractals, fractional operators, scaling effects, and nonlinear dynamics methods that were obtained from 1979 to the present at the Kotelnikov Institute of Radioengineering and Electronics, Russian Academy of Sciences (IRE, RAS). It is shown that new dimensional and topological (not energy!) signs or invariants that are combined under the generalized concept of “sampling topology” ~ “fractal signature” were proposed for the first time and then applied. Texture and fractal-scaling (topological) methods for detecting super-weak signals and fields in intense noise and interferences are proposed. A new type and a new method of modern radiolocation, namely, fractal-scaling or scale-invariant radiolocation was proposed, discovered, and developed. This entails fundamental changes in the structure of theoretical radiolocation, as well as in its mathematical apparatus.

The solution of the tasks assigned to the National Guard of the state implies the presence of certain forces and means with the appropriate technical equipment. A well-known place among such tasks is security of important state facilities. Various physical effects and methods, including radar, are used to create security systems. The development of radar technology and technology made it possible to increase both the quantity and quality of the received information, as well as the use of radar stations for observing living objects. The industry today produces bioradioradars for detecting people and controlling their movements. All samples are made in a single-position version and have a relatively high cost, the fact of their work is easily detected, which facilitates their suppression, including force. In order to increase the secrecy of work, it is proposed to use the methods of separated, more precisely, bistatic location to control the area in front of particularly important objects. The defining detection index is the effective reflective surface (ERS), which is about 1m2for a person. Equipment, weapons and protective equipment contributes to the increase in the ERS. Given the small reflective surface of biological objects, it is proposed to limit the area of responsibility to the sector form in which, at a certain bistatic angle, the effect of a significant increase in the signal/(interference+noise) ratio is manifested. For a specific definition of the gain, it is necessary to choose the operating frequency of the bistatic system and its geometry. For greater secrecy, it is advisable to use the transmitters of radio and television broadcasting, mobile communications, etc. The estimates found, for example, when using digital television transmitters (T2), indicate that the creation of a secretive bistatic system is quite possible – at least in a geometric interpretation.

The task of achieving the resolution in the bandwidth radar with the increased range synthesis aperture for the purpose of recognizing the targets is relevant at the present time, despite significant achievements in this topic. From the point of view of the recognition of objects to a certain type or class of distinction 0.2-0.3 meters is sufficient to solve this problem. However, the problem of obtaining ultra-distinction in a bandwidth radar station with the increased range synthesis aperture requires solving a number of issues, in particular the evaluation of filter parameters for the formation of a flat wave front in a radars with synthetic aperture. One of the solutions of this problem is the inclusion of additional algorithms for the reflected signal processing, which artificially forms a quasi-flat front of the sounding signal wave. In the current article, the question of the selection and evaluation of filter parameters for the formation of a flat wave front in a radar station with ultra-high resolution is being solved. In order to achieve this goal, the article proposes: - a step-by-step procedure for digital filters calculating; - estimation of the number of samples of digital filters with impulse characteristics of finite length in the channels and the observation band; - estimation of the number of samples of impulse characteristics of filters. For the formation of a quasi-flat wave front in a radar station with the increased range synthesis aperture it is necessary to use digital filters with impulse characteristics of finite length and linear phase characteristics in processing algorithms. From the point of view of obtaining minimal losses in the resolution of radar stations with a synthesized aperture along the traveling distance in the process of artificial formation of the flat front of the sounding signal wave, it is expedient to use Chebyshev approximation of the amplitude-frequency characteristic of optimal filters with a minimax error. The width of the transition band of such filters is much smaller than that of other optimal filters with the same values of the countdowns., Задача достижения разрешающей способности в полосовой РЛС с синтезированием апертуры повышенной дальности для распознавания целей является актуальной в настоящее время, несмотря на значительные достижения в этом вопросе. С точки зрения распознавания объектов определенного типа, вида или класса разрешение 0.2-0.3 метра достаточно для решения этой задачи. Однако проблема получения сверхвысокого разрешения в полосовой РЛС с синтезированием апертуры повышенной дальности действия требует решения ряда вопросов, в частности оценки параметров фильтров для формирования плоского фронта волны в радиолокационных станциях с синтезированной апертурой. Для формирования квазиплоского фронта волны в полосовой РЛС с синтезированием апертуры повышенной дальности в алгоритмах обработки необходимо использовать цифровые фильтры с импульсными характеристиками конеч\-ной длины и линейной фазовой характеристикой. С точки зрения получения минимальных потерь в разрешающей способности РСА по путевой дальности в процессе искусственного формирования плоского фронта волны зондирующего сигнала целесообразно использовать чебышевскую аппроксимацию АЧХ оптимальных фильтров с минимаксной ошибкой. Ширина переходной полосы таких фильтров значительно меньше, чем в других оптимальных фильтрах с такими же значениями количества отсчетов импульсных характеристик, амплитудами пульсаций в полосе пропускания и режекции., Задача досягнення розрізнювальної здатності в смуговій радіолокаційній станції із синтезуванням апертури підвищеної дальності дії для розпізнавання цілей є актуальною на теперішній час, незважаючи на значні досягнення в цьому питанні. З точки зору розпізнавання об’єктів до певного типу, виду або класу розрізнення 0.2-0.3 метра є достатнім для вирішення цієї задачі. Проте проблема отримання надвисокого розрізнення в смуговій радіолокаційній станції із синтезуванням апертури підвищеної дальності дії вимагає вирішення ряду питань, зокрема оцінки параметрів фільтрів для формування плоского фронту хвилі в радіолокаційних станція із синтезованою апертурою. Одним з шляхів вирішення цієї проблеми є введення додаткових алгоритмів обробки відбитого сигналу, які штучно формують квазіплоский фронт хвилі зондувального сигналу. В даній статті вирішується питання вибору та оцінки параметрів фільтрів для формування плоского фронту хвилі в радіолокаційній станції надвисокого розрізнення підвищеної дальності дії. Для досягнення зазначеної мети в статті запропоновано: поетапний порядок розрахунку цифрових фільтрів; оцінка кількості відліків цифрових фільтрів з імпульсними характеристиками кінцевої довжини в каналах і смузі спостереження; оцінка кількості відліків імпульсної характеристики фільтрів. Для формування квазіплоского фронту хвилі в смуговій радіолокаційній станції із синтезуванням апертури надвисокого розрізнення підвищеної дальності дій в алгоритмах обробки необхідно використати цифрові фільтри з імпульсними характеристиками кінцевої довжини і лінійною фазовою характеристикою. З точки зору отримання мінімальних втрат в розрізнювальній здатності радіолокаційних станцій із синтезованою апертурою по шляховій дальності в процесі штучного формування плоского фронту хвилі зондувального сигналу доцільно використати чебишевську апроксимацію амплітудно-частотної характеристики оптимальних фільтрів з мінімаксною помилкою. Ширина перехідної смуги таких фільтрів значно менша, ніж у інших оптимальних фільтрів з такими ж значеннями кількості відліків імпульсних характеристик, амплітудами пульсацій в смузі пропускання і режекції.

The article grounds the necessity to develop innovation methods of finding mass of dry raw materials. Today serious problems can be faced in production in case it is needed to find the mass of materials stored in storehouses in bulk. The use of tabular values of material density and humidity can decrease the accuracy of results. Available methods of measuring volume and mass of dry materials, such as visual, theoretical calculation, mine-surveyor measurement, laser 2D-scanning, laser 3D-scanning, radiolocation and acoustic scanning were analyzed. Their advantages and disadvantages were shown. The scientific novelty of the work is connected with innovation, highly accurate, automated method of finding mass of dry hydroscopic materials having different density and humidity, which is based on using the equipment for laser 3D-scanning. The authors propose to measure density and humidity of material at different levels of clamp, which can improve the accuracy of results. The article provides calculations proving the efficiency of the method during stock-taking of material resources at the enterprise. The article pays special attention to problems of stock-taking and registration of shortages in accounting and taxation.

One of the most popular microwave bands now is the W-band. It is attractive by the atmospheric transparency window, which makes it promising for a number of scientific and technical applications including radiolocation, communication, detection of hidden objects and the creation of medical devices. The output power level in both continuous and pulsed regimes for the aforementioned applications should be in the order of several kilowatts and above. This makes the gyrotron one of the most high-potential sources of electromagnetic radiation in this range.The alternate design of an electrodynamic system based on the use of a diaphragm in a wave transition is proposed. This system has been theoretically and numerically analyzed for a W-band gyrotron at the third harmonic of the cyclotron frequency. The optimal parameters of the diaphragm and its position have been selected. With that parameters, the highest value of the starting current of the competing mode is reached while maintaining the starting current of the operating mode. It allows to increase the output radiation power by more than 7 times. An estimate of the accuracy of the manufacturing of the diaphragm has been made. It holds out a hope of scaling this selection method into higher frequency ranges. Further development of this system is primarily tied with a more complex optimization of the system particularly the variation of the length of the cylindrical part of the cavity, which will allow reducing the share of ohmic losses while maintaining high efficiency.The paper is based on the research results, which was conducted in the framework of projects of the Russian Science Foundation No. 17-79-10422. Keywords: Gyrotron, W-band, Mode selection

This paper presents a high-performance microstrip diplexer based on the coupled triangular microstrip cells. The proposed diplexer has a compact size of 0.018 λg2. It is designed to work at 1 GHz for aeronautical military systems and aeronautical navigation and 1.3 GHz for active sensors, GNSS repeaters, radiolocation, and satellite systems. The low insertion and return losses better than 0.21 dB and 25 dB respectively, are obtained at both channels. Another advantage of this diplexer is high isolation of 40 dB between its channels. Moreover, the 1st, 2nd and 3rd harmonics are suppressed with a maximum level of − 30 dB. The designing process is based on proposing an LC model of a novel microstrip cell. Then, the effective parameter on the resonance frequency is found. To verify the designing method, the introduced diplexer is simulated, fabricated and measured. The simulation results are in a good agreement with the measurements.

The problem of increasing the noise-proof feature of communication systems, along with increasing the communication channel capacity, is currently important. In many areas of wireless engineering (in radiolocation and communications for example), it becomes necessary to receive and process signals, some characteristics of which (for example, amplitude, frequency, or initial phase) are unknown. Methods of statistical radio engineering, as well as algorithms for blind signal processing, can be used to eliminate a priori uncertainty. The problem of comparative analysis of some common algorithms for blind signal processing in the tasks of separating radio signals from mixtures with interference and noise was considered. In the study, the algorithms JADE, FastICA, SOBI and AMUSE were considered. Amplitude-, frequency- and phase-shift keyed signals against the background of additive noise, impulse noise and cochannel noise were considered as useful signals. Based on the results of simulation modeling, the effectiveness of these algorithms is compared when distinguishing between several types of signals in the presence of various types of interference. The above research results can be useful when choosing a blind processing algorithm for subsequent practical application.

This paper presents the results of investigations on the beamforming of a low-frequency radio-telescope LOFAR which can be used as a receiver in passive coherent location (PCL) radars for aerial and space object detection and tracking. The use of a LOFAR radio-telescope for the passive tracking of space objects can be a highly cost-effective solution due to the fact that most of the necessary equipment needed for passive radiolocation already exists in the form of LOFAR stations. The capability of the radiolocation of planes by a single LOFAR station in Borowiec is considered to be ‘proof of concept’ for future research focused on the localization of space objects. Beam patterns of single sets of LOFAR antennas (known as tiles), as well as for the entire LOFAR station, are presented and thoroughly discussed in the paper. Issues related to grating lobes in LOFAR beam patterns are also highlighted. A beamforming algorithm used for passive radiolocation purposes, exploiting data collected by a LOFAR station, is also discussed. The results of preliminary experiments carried out with real signals collected by the LOFAR station in Borowiec, Poland confirm that the appropriate beamforming can significantly increase the radar’s detection range, as well as the detection’s certainty.

Agriculture is becoming increasingly reliant upon accurate data from sensor arrays, with localization an emerging application in the livestock industry. Ground-based time difference of arrival (TDoA) radio location methods have the advantage of being lightweight and exhibit higher energy efficiency than methods reliant upon Global Navigation Satellite Systems (GNSS). Such methods can employ small primary battery cells, rather than rechargeable cells, and still deliver a multi-year deployment. In this paper, we present a novel deep learning algorithm adapted from a one-dimensional implementing a convolutional neural network (CNN) model, originally developed for the task of semantic segmentation. The presented model () both converts TDoA sequences directly to positions and reduces positional errors introduced by sources such as multipathing. We have evaluated the model using simulated animal movements in the form of TDoA position sequences in combination with real-world distributions of TDoA error. These animal tracks were simulated at various step intervals to mimic potential TDoA transmission intervals. We compare to a Kalman filter to evaluate the performance of our algorithm to a more traditional noise reduction approach. On average, for simulated tracks having added noise with a standard deviation of 50 m, the described approach was able to reduce localization error by between 66.3% and 73.6%. The Kalman filter only achieved a reduction of between 8.0% and 22.5%. For a scenario with larger added noise having a standard deviation of 100 m, the described approach was able to reduce average localization error by between 76.2% and 81.9%. The Kalman filter only achieved a reduction of between 31.0% and 39.1%. Results indicate that this novel 1D CNN like encoder/decoder for TDoA location error correction outperforms the Kalman filter. It is able to reduce average localization errors to between 16 and 34 m across all simulated experimental treatments while the uncorrected average TDoA error ranged from 55 to 188 m.

There is a need for analog-to-digital converters with high signal-to-noise ratio and large signal bandwidth to solve a number of radiolocation problems. Developing such ADC is a challenge in analog core, digital core and verification. The design flow of the digital core must take into account possibility of changing the analog core specification at any design stage, provide ability to quickly obtain synthesizable RTL code of the device and conduct its functional verification. Automation tools were used to reduce the time spent on development and verification. This article describes the developed software package that generates synthesizable RTL code and verification environment configurations for each stage of development of the analog core of the multi-stage sigma-delta ADC. Results after functional verification are presented.

The chapter is dedicated to the complex of the interrelated issues of design development, fabrication and application of the various antennas and antenna devices for the systems of radiolocation and communications. Here are listed the basic parameters and types of the produced in the world and in Russia systems, examples are cited of the most effective design solutions (including antennas for the potable wireless systems of the standard WIMAX/WLAN), wide band micro strip antennas – with the enhanced gain ratio, wide band microwave antennas of the running wave, clipped directly to garments and even borne on the human body, multiband PAT – antennas, micro strip antennas on the thin substrate, flat reflecting printed antennas for the cellular communications systems, triple range antennas for the systems of uninterrupted communications, original wide band antennas on the ceramic substrate, wide band multi-spiral antennas with polarization and etc., with the detail consideration of the computing methods of these antennas by means of the contemporary means of the automated design development.

The chapter is dedicated to the specific problems and peculiarities of arrangement of the process of designing the radiolocation integrated circuits.

This introductory chapter is dedicated to concise presentation of the theoretical basics of radiolocation. Here in synopsis are represented the theoretical basics of functioning of the radiolocation devices, starting with the chronology of the historical events, related to creation of the first radiolocation stations, description of the basic functional principles of radars, typical algorithms of signal processing (from measurement of the distance to the target, determination of the angle of the target elevation and of the radar definition as per the target), characteristics of aerials (signal amplification, aperture of the aerial, radar’ cross-section, noises and echo-signals), as well as the general information about the radiolocation stations: classification, frequency ranges of work, performance parameters, comparison of the activity zones of the passive range-difference detection systems of the various radio irradiation sources, differences between the military and civil radars.

Обсуждаются некоторые достижения отечественных ученых в области радиолокации, которые широко используются в авиационной технике и космических исследованиях. Рассмотрен вклад научных школ (радиолокационных групп) Д.А. Рожанского и Ю.Б. Кобзарева в формирование и развитие импульсной радиолокации в нашей стране. Под руководством Д.А. Рожанского были начаты первые опыты по использованию импульсного метода радиолокации. Его ученик Ю.Б. Кобзарев с сотрудниками разработал первую радиолокационную станцию (РЛС) дальнего обнаружения самолетов «Редут». Впоследствии Ю.Б. Кобзарев и его ученики создали ряд других РЛС, предложили принципы построения когерентной радиолокационной техники, теорию оптимальной обработки радиолокационных сигналов, заложили основы дистанционного зондирования. Описаны достижения научно-исследовательской группы В.А. Котельникова, стоявшей у истоков планетной радиолокации., Some achievements of Russian scientists in the fi eld of radar, which are widely used in aviation technology and space research, are discussed. The contribution of scientific schools (radiolocation groups) of D.A. Rozhansky and Yu.B. Kobzarev into forming and development of impulse radiolocation in our country is considered. The prime experiments on the usage of the impulse method of radiolocation were started under the direction of D.A. Rozhansky. His follower Yu.B. Kobzarev with colleagues worked out the first radar station «Redut» for the far detection of airplanes. Subsequently Yu.B. Kobzarev and his disciples created other locators, offered the principles of coherent radiolocation technics, the theory of optimal processing of radiolocation signals, laid the foundation of distant sounding. The achievements of research group of V.A. Kotel’nikov which was at the outset of planetary radiolocation are described., Авиакосмическое приборостроение, Выпуск 2 2021

The chapter is dedicated to consideration of such specific independent trend of the radiolocation devices as ground penetrating radars.

The chapter is dedicated to investigation of the peculiarities of construction of the systems for the radiolocation signals digital processing (SDP) on the basis of the microelectronic element base – special purpose microprocessor complexes of the very large scale integrated circuits (VLSIs).

Machine learning (ML) is an important tool for enabling automation in radio access networks. Multiple ML-based applications utilize the device radio-fingerprint, for example to improve network functions such as paging and inter-frequency mobility. The measurements on the plurality of beams in NR can enable the network to get an improved radio-fingerprint in comparison to previous technologies (e.g. LTE), but with the cost of increased overhead in device measurements and signaling. In this paper, the device radio-fingerprint is denoted radiolocation. The increasing use of ML-based applications with detailed radiolocation not only increases the device signaling but also increases the input dimensionality and complexity of the ML model. Hence, it is essential to propose method(s) for reducing the dimensionality by compressing the radiolocation and reducing the overall signaling by downloading such compression method(s) to the device. In this paper, one such solution is proposed, and the challenges in downloading a compression model to the device is further highlighted. Moreover, the performances for two ML applications, namely secondary carrier prediction and beam prediction, with and without compressed radiolocation are compared. The results indicate that a compressed version of radiolocation can achieve prediction performance close to the uncompressed one.

The paper presents the results of studies on analysis, implementation and testing of beamforming methods which can be used for enhancement of radiolocation capabilities of radioastronomical LOFAR station in the context of its use for passive radiolocation. Using the LOFAR system for passive radiolocation might be an highly cost-effective solution for location of objects due to the fact that most of the necessary equipment already exists. In this paper the location of planes by a single LOFAR station in Borowiec was considered as the proof of concept for a more complex system for localizing space objects in the future. The beamforming Phase-Shift algorithm used for passive radiolocation by means of LOFAR station was presented and thoroughly discussed. Beam patterns of steered antenna array of a LOFAR station and its single subapertures, known as tiles, were shown. Occurrence of grating lobes in presented beam patterns is also discussed. The results of preliminary experiments performed with real signals registered by the LOFAR station in Borowiec confirm the efficiency regarding enhancement of radiolocation capabilities, increasing radar’s range and certainty of detection by means of beamforming.

The capability of passive radar employing radio telescope as a receiver and digital radio broadcasting (DAB+) as an illuminator of opportunity is analyzed in the paper. The principle of LOFAR radio telescope is presented with deep analyses of using such radio telescope as passive radar for detection of aerial (airplanes) and space (satellite) targets. The theoretical considerations are illustrated by the description of signal processing schema and presentation of measurement results.

This paper provides a brief description of an alternative method for the direct electrodynamics problems solving. The method is being developed for its application in subsurface radiolocation and flaw detection, primarily. One of the main features of the approach is it possible application to solving the direct problem of several bodies, boundary irregularities accounting and complex-dielectric media consideration. The basis of our approach is the principle of electrodynamic equivalence of a radiating and scattering body. This method may be used, as when considering heterogeneity, as well for the buried source detection.

In the report questions of assessment of efficiency of recognition of radio-emitting objects with use of set of signal signs both the systems of radiolocation, and communication systems and controls are considered. Results of experimental studies on the basis of these objects taking into account parameters of onboard radars and communication systems are provided.

The six-port reflectometers are used for measuring the parameter of microwave signals and tracts in microwave drying and heating plant, telecommunication, radiolocation, medicine. One of the six-port reflectometers type is multiprobe microwave multimeter which microwave block is tract section with sensors. The problem considered in the report is sensors re-reflection in the microwave block of multiprobe multimeter. Earlier research using a signal flow graphs model not satisfy because ambiguity of the result. So we try another mathematical model. The proposed model of sensor re-reflection uses method of induced emfs and dyadic Green functions. The novelty of proposed approach is to determine the parameters of the scattering matrix of multiprobe microwave multimeter through the impedance matrix, and find the impedance matrix by the method of induced emfs

Humans have always wanted to determine positions in an unknown environment. At the beginning, methods were simple. They were based on the observation of characteristic points&mdash, in the case of shipping, additional observations of the coastline. Then came navigation based on astronomical methods (astronavigation). At the beginning of the XX-th century, a new way of determining the current location was developed. It used radio wave signals. First came radio beacons, then ground-based systems. Currently, satellite systems are being used. At present, the most popular one is the Global Positioning System (GPS). This system is fully controlled by the Department of Defense, and only the U.S. forces and their closest allies have been guaranteed the accuracy offered by the system. Armies of other countries can only use the civilian version. This situation has engendered the need for an independent radiolocation system. This article describes the construction and operation of such a technology demonstrator that was developed at Gdansk University of Technology. The main advantage of the system is the ability to manage it without the chain organization of the reference stations, which currently work with each other asynchronously. This article demonstrates the functionality of such a system. It also presents results and analysis of its effectiveness.

This paper is devoted to studying the applicability of impulse radiolocation method in microwave range (1700 MHz) with the use of transmit and receive GPR antennas in order to measure contact wire position of electrified railways. Results showed that basing on triangulation principle of object distance measurement GPR method can be applied to identify contact wire geometric parameters: height, stagger, mast distance, line events (signals, crossings, points etc.).

The features of the functioning of coastal radar information support, monitoring and control of the movement of marine vessels in the cramped conditions of navigation are examined and analyzed. The general issues and features of the optimization of digital processing of coordinate information in the near-radar sensing of extended marine objects under the influence of passive interference caused by the presence of the underlying sea surface and hydrometeorological formation in the form of rainfall are formulated and analyzed. Simple and effective digital algorithms have been developed for determining the azimuthal range-finding coordinates of extended objects from selected single and dispersed binary signal groups belonging to an extended radar object. The coordinates of the conditional geometric center, determined in accordance with the developed method, do not contain errors associated with the presence of a jib-trace. The results obtained by estimating the amount of mixing of the object when it moves along the channel are within the range of the real-expected values ΔD ≈ 15 meters. The developed method and its practical implementation are quite simple and effective in providing information support to the skipper in the process of escorting the vessel along the channel. Results fulfilled research in future will use in solving problem of determining the coordinates of the location of extended maritime object, as well as in the solution of similar problems when designing digital radar technics., Рассмотрены и проанализированы особенности функционирования береговых радиолокационных средств информационной поддержки, контроля и управления движением морских судов в стесненных условиях мореплавания. Сформулированы и проанализированы общие вопросы и особенности оптимизации цифровой обработки координатной информации при радиолокационном зондировании протяженных морских объектов в условиях влияния пассивных помех, обусловленных наличием подстилающей морской поверхности и гидрометеообразований в виде дождевых осадков. Разработаны простые и эффективные цифровые алгоритмы определения азимутально-дальномерных координат протяженных объектов по выделенным одиночным и рассредоточенным бинарным сигнальным группам, принадлежащим протяженному радиолокационному объекту. Определяемые в соответствии с разработанным методом координаты условного геометрического центра не содержат погрешностей, связанных с наличием кливерного следа. Результаты оценки величины смещения объекта при его движении по каналу находятся в пределах реально ожидаемых значений ΔD ≈ 15 м. Разработанный метод и его реализация достаточно просты и эффективны при информационной поддержке судоводителя в процессе проводки судна по каналу. Результаты выполненных исследований будут использованы при решении задачи определения координат местоположения протяженных морских объектов, а также при решении аналогичных задач при разработке цифровой радиолокационной техники., Розглянуто та проаналізовано особливості функціонування берегових радіолокаційних засобів інформаційної підтримки, контролю та керування рухом морських суден в умовах обмеженого простору мореплавання. Сформульовано та проаналізовано загальні питання та особливості оптимізації цифрової обробки координатної інформації при радіолокаційному зондуванні протяжних морських об’єктів в умовах впливу пасивних завад, обумовлених наявністю підстилаючої морської поверхні та гідрометеоутворень у вигляді дощових опадів. Розроблено прості та ефективні цифрові алгоритми визначення азимутально-дальномірних координат протяжних об’єктів за виділеними одиночними та розосередженими бінарними сигнальними групами, що належать протяжному радіолокаційному об’єкту. Координати умовного геометричного центру, що визначаються у відповідності з розробленим методом, не містять погрішностей, пов’язаних з наявністю кліверного сліду. Отримані результати за оцінкою величини зміщення об’єкту при його русі по каналу визначаються у межах реально очікуваних значень ΔD ≈ 15 м. Розроблений метод та його практична реалізація досить прості та ефективні при інформаційній підтримці судноводія в процесі проведення судна по каналу. Результати виконаних досліджень можуть бути використані при розв’язанні задач визначення координат місцеположення протяжних морських об’єктів, а також при розробці цифрової радіолокаційної техніки.

This paper presents the possibility of using a pseudo-distance method (PDM) for determining the radio radiation source (RRS) of coordinates in multi-position passive systems. The main advantages of multi-position passive systems are reached by processing of information, received in the separated points of space. Advantage of proposed method in comparison with the range-difference method (RD) is an estimation of time of emission of RRS signal in a scale of receiving stations. Features of transition from PRM to distance-measurement method (DM) under condition of an estimation of the period of emission of radio signals are resulted. Results of modeling of various methods are shown and the advantage of modified in accuracy determination of coordinates of RRS in comparison with RD is shown. Advantages of PDM usage in areas with a large value of horizontal delusion of precision (HDOP) are presented. Expediency of the period of emission filtration for greater accuracy is presented.

Application of multi-frequency radiolocation allows to expand essentially received signals spectrum that increases amount of a target (object) classification identifiers including thermal portraits for radiometric measurements. In this paper it is represented a prototype of measuring radiometric unit allowing to carry out simultaneously contactless radiometric research of liquids in two wavelength ranges: 8-mm and 3-mm. It is developed the method of definition of parameters of capacity (container) where liquids are placed. It is estimated an influence of caustics appearing in case of waves reflections from internal wall of container and also on quality factor, attenuation coefficient and relative factor of container which are distantly measured. In two frequency ranges there are carried out researches of two water solutions and oil processing products (gasoline, dissolvents, diesel fuel). It is shown the liquids with close thermal portraits in identical frequency band due to close physical-chemical parameters, can have different thermal portraits obtained in different frequency bands reflecting dispersion properties of the liquids and they can be used for liquids identification visually or in case of received data processing.