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A new method for a location service in the asynchronous wireless sensor networks is outlined. This method, which is called asynchronous time difference of arrival (ATDOA), enables calculation of the position of a mobile node without knowledge of relative time differences (RTDs) between measuring sensors. The ATDOA method is based on the measurement of time difference of arrival between the node and the same sensor at the discrete time n and n + 1 , and the solution of a nonlinear system of equations. The paper concentrates on the description of the method, solving the nonlinear system of equations and simulation results.

A study is made to define a procedure of cooperative processing of goniometric and range difference measurements in multilateral system of passive radiolocation. As a result, we worked out the computational algorithms, which implement this procedure. The accuracy characteristics are estimated.

To determine movements of infrastructure objects on Earth surface, SAR interferometry is used. The method is based on obtaining a series of detailed satellite images of the same Earth surface area at different times. Each image consists of the amplitude and phase components. To determine terrain movements the change of the phase component is used. A method of persistent scatterers detection and estimation of relative shift of objects corresponding to persistent scatterers is suggested.

An angular--energy method for the combined estimation of the generalized radiolocation coefficient and range to the moving emitting target using the results of bearing and received signal amplitude measurements is developed based on a single-position passive location system. Depending on the constraints imposed on the generalized radiolocation coefficient, two cases are considered, the stationary and nonstationary ones. The working region of the method in range estimation is studied. The results of estimation of the method's efficiency are presented.

The possibilities of early detection of serious accidents at NPPs by using passive microwave radiolocation are discussed. Estimates of the brightness and antenna temperature of a partially ionized cloud created by the first emission of γ-radiation from the Chernobyl NPP are presented. It is shown that the microwave radiation can be detected by means of modern radiometers placed in low-flying satellites and airplanes as well as on stationary ground-based platforms.

In the article identified a tendency of combined platforms hardware tools radiofrequency and digital signal processing for general solution communication and radiolocation tasks. The analysis of developments in the application of mobile communication of GSM standard to solving problems for airspace radar control. An analysis of developments in the area of the use of mobile communication GSM standard for solving problems of radiolocation control of airspace were made. Investigated the use of digital technology of beam forming to detect air targets with the help of mobile communication systems. Presented the results of research upper limit radio emission cellular communication systems. Appropriate researches were made by the authors during an ordinary regular flights of passenger airliners, using smartphone IPhone 5S, which was switched on mode satellite navigation to determine the current flight altitude and location coordinates. At the same time on the display of smartphone was monitored indication of presence connection with terrestrial cellular base stations appropriate for that or another locality operator communication services. Substantiated creating air space control system for the needs of special users Ukraine based on existing GSM networks.

Introduction. This article contain short introduction to history of complicated signals and list of common sequences, used in spectrum spreading. Method of creating Kasami sequences. In this article is shown sequence creation method, based on method of creating maximum length sequence. Creating of the structural schema of Kasami sequences generator. Principles of construction of Kasami sequence generator are shown in this article. Example of generator for sequence with length 63 symbols, which are created using method, mentioned in previous article, is also shown. Spectrum of Kasami sequences. This article contain amplitude and phase spectrum of two Kasami sequences with lengths of 1023 and 255 symbols. Theoretical formulas are created using Discrete Fourier Transform operation, and graphics are plotted using Fast Fourier Transform operation. Phase spectrum data are also been changed by unwrap operation for better visibility. Conclusion. This article contain analysis of characteristics of previously shown spectrum. Several conclusions are made about correlation between sequence and spectrum characteristics. These conclusions include that made about amplitude spectrum form dependence of sequence length, type and basic impulse characteristics.

The automatic identification system (AIS), a ship reporting system originally designed for collision avoidance, is becoming a cornerstone of maritime situational awareness. The recent increase of terrestrial networks and satellite constellations of receivers is providing global tracking data that enable a wide spectrum of applications beyond collision avoidance. Nevertheless, AIS suffers the lack of security measures that makes it prone to receiving positions that are unintentionally incorrect, jammed or deliberately falsified. In this study, the authors’ analyse a solution to the problem of AIS data verification that can be implemented within a generic networks of ground AIS base stations with no need for additional sensors or technologies. The proposed approach combines a classic radio-localisation method based on time difference of arrival with an extended Kalman filter designed to track vessels in geodetic coordinates. The approach is validated using anonymised real AIS data collected by multiple base stations that partly share coverage areas. The results show a deviation between the estimated origin of detected signals and the broadcast position data in the order of hundreds of metres, therefore demonstrating the operational potential of the methodology.

Neural network that allows to make a decision about the presence or absence of monomolecular films of medium or heavy oil on the sea surface in the radar with horizontal polarization, integrated into a single system with passive reflectors located either on the perimeter of the port basin, or on special buoys at sea is proposed.

Abroad spectrum of materials is considered, developed and used within ONPP Tekhnologiya for manufacturing radioparent domes for different types of aircraft. Theoretical and experimental development is carried out in the enterprise, and optimum structures are determined for the walls of antenna domes made from different composite materials taking account of a set of operational effects in aircraft, providing creation of broadband radiolocation systems with improved structural strength by not less than 10%; optimum production methods and a scheme for manufacturing complexly shaped domes are provided, including those based on multilayer structures of heat-resistant radioparent composite materials.

We propose a basis for the arrangement of an experimental installation for the investigation of the possibility of coherent accumulation of echo signals from objects with nonlinear electrical properties (ONEPs) in a synthetic aperture antenna or synthetic aperture radar (SAR). We established experimentally the dependence of the signal-to-noise ratio (SNR) on the accumulation time, confirming the possibility of coherent accumulation of signals.

The possibility of applying short-range radiolocation in millimeter wave range for problem of remote identification of flammable and hazardous liquids, enclosed in dielectric containers is demonstrated for the first time. Developed measurement setup allows indoor investigations; and the level of emitted power of utilized devices is insignificantly higher than background noise level, or, equivalently, thermal radiation. The described radiometric measurement setup enables discriminating liquids having different physical and chemical properties, in particular discriminate between water and gasoline containers. Applying additional illumination, which increases the contrast of the object under test, is one of one of the features of developed design. Various noise sources were investigated to be used as additional illumination. It was shown that in case of short-range radiolocation, energy-efficient fluorescent lamp is the most affordable choice of radiometric illumination. Such lamp not only ensures sufficient noise level in the operating frequency domain, but also has in-built modulation device that allows using modulation regime of the receiver and enables higher sensitivity.

Revolutionary progress in the photonic technology provides the ability to develop military systems of new properties not possible to obtain with the use of classical technologies. In recent years, this progress has resulted in developing advanced, complex, multifunctional and relatively cheap Photonic Integrated Circuits (PIC) or Hybrid Photonics Circuits (HPC) built of a collection of standardized optical, optoelectronic and photonic components. This idea is similar to the technology of Electronic Integrated Circuits, which has revolutionized the microelectronic market. The novel approach to photonic technology is now revolutionizing the photonics’ market. It simplifies the photonics technology and enables creation of technological centers for designing, development and production of advanced optical and photonic systems in the EU and other countries. This paper presents some selected photonic technologies and their impact on such defense systems like radars, radiolocation, telecommunication, and radio-communication systems.

The issue of radar visibility reducing of objects is currently very topical. Interest in this subject is due to the variety of different radars, reconnaissance drones and homing rockets and other high-precision weapons. The most popular way of radar visibility reducing of complex shape target is applying of radio absorbing cloak and optimization of the object design. However, both methods have their own drawbacks, one of which is the high cost of radio absorbing materials and difficulty in changes in design of finished object. Thus it is apparent, that one needs for some kind of method, which would allow assessing the contribution of each radar visibility reducing method. In this paper the angular dependence of the radar cross section data for the two on-ground facilities are compared. Radar data processing method with new introducing quantities is proposed. This method allows getting quickly and accurately assessing to the data about visibility of the facility, located on any of the underlying surfaces, as well as evaluating the effectiveness of visibility reducing events.

As the need to satisfy the global demand for wireless services continues, the pressure for valuable spectrum adjacent to radiolocation services is a topic of contention between incumbent spectrum users and national spectrum policy makers and regulators. The study of the coexistence of radar systems and modern LTE communications systems tend to focus on the measurements of the spectrum impacts of the radar transmission and the interference assessment of the LTE base station receiver. The study and measure of impact on the radar receiver has been studied mainly in theory. In this paper, the methodology and technique for benchmarking the radar receiver performance of cooperative radar systems in the presence of wireless systems is proposed.

The major trends of the development of radiolocation, navigation and communication 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 high resolution and noise immunity. Direct digital synthesizers (DDS), developed on the basis of the direct digital synthesis method, have unique technical characteristics and allow improving the parameters of radio engineering systems considerably.

This article discusses the possibilities of the location of aircraft via active and passive radiolocation systems. The next part is dedicated to location recording of the aircraft, which uses the general type of Radiolocation Warning Receiver by triangulation method and PG method. Then we examine the analysis of the measured data with the purpose of determination of the location of source radiotechnical signal, using the general calculation algorithm and map image. Finally, we check the relevance of the results via graphical analysis, which was based on line of sight and special software computing.

Ultra-Wideband (UWB) technology completes available technologies of fast data links on short distances and brings new possibilities, e. g. clear identification and possibility to locate each active element in space precisely. Usual applications include various types of precise positioning systems or radiolocation display systems, however, transferring images in very high definition is also expected. One of the leaders in UWB technology production is DecaWave which provides an integrated solution (e. g. DW1000 integrated circuit) and many ready-made implementation solutions. This article was created to help to verify measuring methods and UWB signal analysis using available technology and testing AKRS (Radiosignals Analysis and Classification) system features to use these signals. The result consists of graphs of actually measured curves of analysed quantities which have not been published to this extent yet. They include spectral and time analyses; modulation type, framing and data conversion to bit content are explored. When procedures to measure and analyse UWB DecaWave TREK1000 system radio signals were tested, specific characteristics emerged out of usage of these systems. Catalogue values specified by the manufacturer were verified during the analysis and many other facts that could not be looked up otherwise were determined.

Detection and localization of vessels can be carried out by exploiting the radiolocation approach. Nevertheless, the employment of radiolocalization far from the shore can be limited by the lack of enough receivers to perform a correct multi-lateration of the RF source. In order to solve this gap, mobile assets or base stations from different networks need to be exploited. In particular, within a given search area, a ship could deploy low-cost receivers on drifting buoys, balloons or RPAs, creating a network with several nodes.

In the paper we consider the radiolocation equation for Incoherent Scatter Radar (ISR) method, which accounts for refraction effect and Faraday rotation in VHF frequency domain. Investigation shows that refraction cannot be ignored in incoherent scatter data processing when lag product is used for obtaining of ionospheric characteristics. Effect of refraction is responsible for specific distortions of incoherent scatter spectrum and shows that together with “ion line” of incoherent scatter spectrum a relatively small “electron line” also plays a significant role in forming of ionosphere response as an additional wide band “radar induced” radiolocation signal that depends on ionospheric temperature and ion composition. The presence of the wide band “electron line” plays significant role in three dimensional forming of the ionosphere response inside the ISR antenna diagram pattern. During the testing experiment we found that ISR “electron line” can be measured at much higher altitudes comparing to the “ion line”, so that the results of the present study can be implemented for improvement of incoherent scatter technique. • Radiolocation equation with account for refraction is developed for Incoherent Scatter technique. • First result of electron scattering measurements on Irkutsk ISR is presented.

The design of high antennas for wireless communication is very essential. The main drawback of the microstrip patch antenna is the low gain. The Metamaterial superstrate layer along with antenna structure improves the antenna performance parameters like gain and bandwidth. Due to Ultra refraction phenomenon, radiation is concentrated normal to the patch so that unwanted sidelobes can be avoided. This review paper shows different techniques to increase the gain of the antennas such as use of metamaterial substrate or super-strate. Also substrate materials and feeding techniques of the antenna are varied to reduce the return loss. By changing the thickness of the substrate, bandwidth of the antenna is increased. Slots of the antenna are adjusted to enhance the gain and bandwidth. The main applications of the microstrip antennas are WiMax, medical imaging and radiolocation applications.

The design of a dual band microstrip Caution Patch antenna useful for private land mobile and aviation applications has been proposed in this paper. Under these applications, the design may encompass fixed satellite services, mobile except aeronautical mobile, radiolocation and aeronautical radio navigation. The FR4 epoxy substrate having a relative permittivity of 4.4 and a thickness of 1.6 mm is used. The utilized probe feeding technique is simple to fabricate and match, provides low spurious radiations and is simple to match by controlling the position. The antenna resonates with a peak gain of 6.3 dBi at 3.52 GHz offering a bandwidth of 111.9 MHz and yet another at 4.39 GHz with a gain of 20.4 dBi and a bandwidth of 8.02MHz.

In this paper the investigation on the special aspects of usage of broadband chaotic signals in the systems of precise positioning and radiolocation is done. The results of the numerical experiment on the investigation of the influence of the productivity of the analog-digital converter (ADC) and additive white noise in the radio channel on the performance and working efficiency of the system are presented. As the probing signal the real chaotic microwave broadband signal is used, generated as the result of the experimentation with a microwave generator of chaotic oscillations based on IMPATT diode. The results of comparison of resistance to destabilizing factors of the two main methods of processing of chaotic probing signals are discussed. These are the correlation method and the method of double spectral processing.

Рассмотрен метод дистанционного контроля систем вторичной радиолокации (ВРЛ) на основе использования удаленного пункта контроля (УПК), на котором осуществляется анализ запросных и ответных сигналов с целью определения местоположения воздушных судов (ВС) и сравнения результатов с работой контролируемых систем. Выявлены источники ошибок, влияющих на точность работы системы дистанционного контроля (СДК), и найден допустимый уровень данных ошибок для обеспечения требуемой точности. Определена степень влияния каждого из рассмотренных видов ошибок на результат работы СДК. Проанализирована статистика случайной ошибки в определении местоположения ВС в СДК. Проведено сравнение точности работы СДК и контролируемых моностатической и бистатической систем ВРЛ для различных расположений ВС относительно УПК и радиолокационного запросчика. Предложены рекомендации по расположению УПК для обеспечения максимально возможной точности работы системы., The paper considers a method of remote control for Secondary Surveillance Radar (SSR) systems based on using a Remote Analysis Station (RAS), which analyzes the request and response signals for the purpose of locating aircraft and comparing the results with the performance of the controlled systems. We have identified the sources of the errors that affect the accuracy of the Remote Analysis Station (RAS) and established the level of these errors acceptable for ensuring the required accuracy. The degree of influence that each of the considered types of errors has on the performance of the RAS is determined. The statistics of aircraft position errors by the RAS is explored. The accuracy of the RAS and the controlled monostatic and bisatic SSR for different aircraft position depending on the SSR and receiver positions is compared. The comparison provides recommendations about the RAS location to provide maximum remote control system (RCS) accuracy.

Gyro-devices provide the highest CW or average power of microwaves in centimeter, millimeter and submillimeter wavelength ranges and therefore they are very attractive as microwave sources for many of applications such as plasma fusion, radiolocation, ion sources, telecommunication, technology, spectroscopy and some other. In last years an essential progress in the device development was demonstrated. The paper presents State-of the Art in the device development, new demands in the parameters enhancement and possible ways to achieve the goals.

Narrowband signal model, which approximates Doppler effect as a frequency shift, is inappropriate for some problems of radiolocation, hydroacoustics or passive location. In this case it is necessary to use Doppler stretch (time-scaling) as a signal parameter. In this paper Cramer-Rao lower bound of joint Doppler stretch and delay estimation for wideband signal model is derived. Maximum likelihood estimations in presence of nuisance parameters can be obtained by two ways. First method implies estimation of all unknown signal parameters and subsequent rejecting of nuisance. Second method involves averaging of conditional probability density function by nuisance parameters with considering it's priori probability density. Although Fisher information matrices of signal parameters are different for specified methods, estimation variances of Doppler stretch and delay are equal. In wideband signal model, the variance of time delay estimation depends on choice of reference axis. Varying the reference time leads to modifying of measurement moment with respect to signal. Since time delay is various parameter, its estimation variance is also variant. Appropriate choice of reference time results minimization of estimation variance and diagonalization of FIM. In the narrowband limit proposed consideration results in well-known CRLB of Doppler shift and delay estimation.

Space communication systems are the integral part of modern informational systems, in-cluding low rate (telephone and paging) as well as high rate (internet, high resolution TV) services. As a result of omni-increasing needs in quality, rates and capacity of transmitted information, space systems draw a large part of SHF range. These systems consist of shuttle group near the Earth orbit and surface stations. One of the tasks being solved at development is the analysis of stability of last-named to electromagnetic influences of different kinds. For solving this task the collaborators of “Nanophotonics and optoelectronics” laboratory of Southern federal university have developed and examined the prototype of surface station of space communication system using “radio over fiber” technology. Designed prototype consists of two blocks – base station and transmitting device, connected to each other with singlemode fiber optic cable. Between them occurs the SHF signals transmission in the range of 1500-2500 MHz. The use of fiberoptic link for modules connection is caused with its high noise immunity. The information is transmitted in the form of two level phase code manipulation, preliminarily differentially coded. Transmitting device contains terminal cascades of amplification and element of power interferences protection. Working modes control and system parameters settings are implemented with means of personal computer, linked to base station. Given are the results of prototype sensitivity experimental examination, which have shown the device compatibility for holding full-sized testing.

Considering that the frequency band 77.5-78 GHz is allocated to the radio astronomy service on a secondary basis, and the World Radio communication Conference 2015 has allocated the frequency band 77.5-78 GHz to the radiolocation service for automotive radar applications on a primary basis. In this paper, the coexistence studies for the automotive radar with the radio astronomy service, is presented. The protection of the RAS may require additional measures in some countries, such as the definition of specific exclusion zones around RAS sites.

Types of ballistic configuration of the satellite formation for Earth remote sensing for interferometric imaging using a synthetic aperture radar antenna are considered. Possible configurations for multiposition satellite formations are provided.

This paper presents the results of the research considering the in uence of the initial frequency on linear frequency modulation signal compression. The signal compression has been performed using the digital matched ltration in the time domain. The ratio of peak to side lobe ratio with the width of the main lobe equaling one sampling period is the measure of the quality of compression. In general, a lower value of peak to side lobe ratio is obtained for linear frequency modulation signals with a non-zero initial frequency than with a zero initial frequency. The peak to side lobe ratio is systematically decreasing with the increase of the initial frequency f1. The existing methods of band signals sampling, where the spectrum of the signals is transferred by means of the carrier signal f0 of a signi cantly higher frequency than the band B (f0 B) may be e ectively used for sampling signals considered in this study, which do not have a carrier. As a result, for the linear frequency modulation signals with a non-zero initial frequency f1 = nB and a nal frequency f2 = (n + 1)B, n = 1, 2, . . ., the same peak to side lobe ratio values will be obtained as for linear frequency modulation signals with a zero initial frequency and the identical band and time duration. The results of this research could be implemented in sonar and radiolocation techniques and medicine.

In this article the author makes an attempt to characterize the factors which are to be taken into consideration while designing the ground radar component of Air Defense systems, in order to enable them to operate on the modern battlefield. He presents the latest theoretical views on the relationship between the usage of anti-radar weapons and the organizational and technical defense mechanisms which can be deployed against such weapons. In particular the author emphasizes the protection of radars against anti-radiation missiles (ARMs) which present the biggest threat for effective Air Defense systems. He also stresses the need to combine radars into one system which enables the streamlining of their work parameters and thus ensuring their complex usage. The gaining of those capabilities will guarantee that the parameters of the air surveillance radar zone can be defined effectively.

Bioradiolocation was used to test respiratory disorders in sleeping humans. Specifications of a bioradiolocator for non-contact monitoring of motion in sleeping humans during long-term isolation are described. An algorithm for isolation of motion activity from the signal detected by the bioradiolocator is suggested. The results of the processing of bioradiolocation data obtained by the international research program MARS-500 (simulation of international space flight to Mars) are discussed.

The manifestations of mesoscale and submesoscale eddy elements in surface currents of the Baltic Sea in satellite images differing in physical nature and spatial resolution are considered. The investigation is based on the Envisat ASAR and ERS-2 SAR high-resolution radiolocation images (RLIs) obtained in 2008–2009 for different sites of the Baltic Sea water area and the use of the Envisat MERIS and Landsat ETM+ radiometric images of the visible spectrum. Possible mechanisms of the appearance of eddy structures in RLIs of the Baltic Sea water area are considered. Joint analysis of the mentioned data revealed specific features of the appearance of eddy structures in satellite images, taking into account the variability of optical characteristics of Baltic Sea surface waters during the summer blooming of cyanobacteria and the spring blooming of diatomic algae.

Drastic propagation conditions in wireless environments, specifically the presence of non-line-of-sight (non-LOS) propagation in urban areas, pose a major challenge to the acquisition of location information. Count-of-Beacon (COB) is a new radiolocation technique where the absence of a LOS path does not degrade the precision of the estimated position. In this technique, the distance between a mobile terminal and a base station can be derived by means of the geometry of overhearing. The geometry of overhearing models the correlation between the position and the proportion of overheard power-controlled beacon packets. However, the deviation of the attenuation that signals experience, mainly due to shadow fading, has not been considered in this model. This paper reformulates the geometry of overhearing by focusing on the effects of shadow fading. Simulation results are used to verify the validity of the new derived model at different levels of shadowing. The closed-form expression of the Cramer-Rao lower bound (CRLB) is also derived to benchmark the accuracy of the COB technique. In addition, the major source of error affecting the precision of the COB technique is identified and its statistical description is provided.

Described is Fourier algorithm of recurrent conversion providing increased resolution, absence of false petals, possibility of spectral analysis of signals of very large duration. The algorithms can have a broad band of applications in radiolocation, hydrolocation, synthesis of speech and music, image and seismogramme processing and many other areas

International audience; In the specific context of wearable wireless networks, this work aims at improving the accuracy and the robustness of radiolocation solutions based on standard narrow-band radio technologies for user-centric mobile applications. The proposed solution takes benefits from off-body or body-to-body radio links, with respect to fixed elements of infrastructure or to other mobile equipped subjects, respectively. The main idea is to infer relative angular information between the carrying body's heading and the median direction of arrival of received signals. For this sake, we rely on differential received power measurements issued at judiciously placed on-body nodes. Light calibration procedures (e.g., based on the full-scale dynamics of observed measurements) and joint absolute position/orientation estimation algorithms then enable to cover both individual/non-cooperative and collective/cooperative navigation needs. The performance is assessed by means of field experiments with IEEE 802.15.4-compliant integrated devices operating at 2.4 GHz and an optical motion capture system delivering the ground truth reference. On this occasion, our proposal is shown to be resilient against mobile Non-line of Sight (NLoS) situations (e.g., in crowded environments).

Wireless communication technologies use the radio waves to transfer information between two or more devices that communicate. Propagation of electromagnetic waves through free space can be used for communication or for positioning and navigation. One of the basic principles of the device for positioning, which works on the basis of receiving and transmitting radio waves, is the measurement of time of propagation of electromagnetic waves. Device transmits electromagnetic pulse of certain strength and duration in the free space, on the basis of the reflected echo of the same pulse (e.g. time delay, signal strength) the parameters of the target are determined. Parameters of target may be its distance, azimuth, elevation, and information on the movement of the target (speed, direction of movement). In some cases it is possible to determine the type of target, for example, what kind of flying objects is moving. In general, it can be said that the problem of radiolocation can be reduced to measurement of the distance between multiple wireless terminals participating in the position measurement. The need for the location of wireless terminals is growing due to the large number of applications that benefit from such information (military purposes, industry, medicine, commercial services).

The correlation methods for signal receiving are widely used due to wideband electronics systems development. This technique gives high improvements for device features. Correlation methods are nowadays used in microwave metrology, radiolocation, medicine and in military applications in particular. In this place it should be mentioned: FMCW radars, noise radars, direction finding systems for electromagnetic radiation sources. In medicine it is measurement possibility for human living features, that as breath or heartbeat. In radiolocation this one is used for special applications, that as through the cover observation (the building wall for example) or ground penetration. The detector circuit consist of four 3dB, 180° hybrid couplers, phase shifter and four microwave detectors. Wide band of signal correlation about fg/fd = 3, it is obtained due to working in microwave band and using Shottky diodes as multiplying elements. Proposed phase detector can be used as the wideband correlator for microwave signals.

Most of PCL algorithms require clear, non channel-distorted reference signals. However radar systems operate under various environmental circumstances, including dense, multi-path urbanized areas. GSM transmission has built-in mechanism to estimate and overcome multi-path effect. It is good enough for demodulation however not sufficient for PCL applications. The paper presents SVD (Singular Value Decomposition) based method for channel estimation. The method is evaluated and compared to Least Squares (LS) approach and structured channel estimation on simulated GSM transmission.

An electrically small circular loop antenna with an isotropic radiation pattern to within ± 1.9 dBi is described. The scalable design operated at the 1575.42 Megahertz Global Positioning System L1 frequency. Means are provided to separately adjust driving resistance and reactance. Common mode currents radiate beneficially as part of loop structure. As the radiation pattern is sufficiently spherical, the design permits wireless systems to operate without aiming or orientation. Applications may include radio frequency identification (RFID) tags, radiolocation receivers, tumbling satellites or personal communications.

The radio systems transition to a discrete messages transmission applying broadband technology led to significant progress toward improving both energy and frequency efficiency in radio resources use. Thus, the use of matched windowing of non-stationary signals in the implementation of coherent processing algorithms is shown in this report. The obtained research results show the efficacy of windowing in the optimal processing algorithms construction for narrowband signals

Полный текст доступен на сайте издания по подписке: http://radio.kpi.ua/article/view/S0021347016080021 Работа выполнена при поддержке гранта РШ-7116.2016.8 This study was carried out with support of grant No. RSh-7116.2016.8 Estimation algorithms of coordinates of the Earth surface elements in 3D radio-wave imaging system based on the airborne Doppler radar during the low-altitude flight were proposed. In addition, the applicability of the algorithms was demonstrated by using the computer simulation method Предложены алгоритмы оценивания координат элементов земной поверхности в системе 3D-радиовидения на базе бортовой доплеровской РЛС маловысотного полета. Показана применимость алгоритмов методом компьютерного моделирования.

This study examines the impact of an input band-pass filter on the reception of phase-shift keyed signals (PSKS) with gradual phase change against the background of noises. In the case under investigation PSKS are received by a correlation receiver during the radar detection of targets. Analytical expressions of the target detection characteristics were obtained for PSKS with random initial phase and the amplitude containing regular and fluctuating components. This study also examines the relationships of the detection characteristics as a function of the input filter band-pass and the interval duration of gradual phase change.