All-Russian Scientific Research Institute of Radio Engineering

Abstract The article presents a mathematical apparatus of radio wave tomosynthesis for obtaining a radar image using an ultra-wideband multi-channel antenna array. Also presented are the results of processing radar data and the resulting three-dimensional radio tomogram of inhomogeneities in a homogeneous layer. Using the example of restoring the shape of test objects, the possibility of isolating individual layers at the required depth is shown. By combining radio wave and video information, the possibility of implementing augmented reality is shown. This combination provides a more visual interpretation of GPR data in construction and repair tasks.

Attention focuses on the design of radio-transparent aircraft fairings, taking account of the required strength and mass-centering radioelectronic characteristics and the ambient temperature, using a specific mathematical apparatus. It is established that thermostable and thermoreactive binders are promising in the manufacture of frictional components and as high-temperature thermal insulation in critical aerospace components. Analytical formulas permit selection of the preliminary fairing design and specification of the minimal wall thickness in the early stages of design. The finite-element method may be used in ensuring the shape, stability, and strength by modeling the stress–strain state of radio-transparent composite structures.

The transmitting antenna of a medium wave radio navigation system in the presence of a reradiating object is considered. The change in the phase radiation pattern under variations of the underlying ground surface parameters is analyzed. It is shown that the phase pattern non-uniformity can reach tens of degrees. A distortion compensation method is proposed using a phase pattern calibration that takes into account the influence of surrounding objects and a small calibration antenna that allows tracking of changes in ground parameters.

The possibility of using panel antennas with slant polarization to ensure uniformity of the circular radiation pattern when placing digital radio broadcasting antennas of DRM+ standard and analogue FM radio broadcasting on towers with a large (12 meters) cross-section is considered. The calculations showed the possibility of achieving a positive effect, as well as the possibility of using smaller reflectors and forming a sectoral radiation pattern. The possibility of using the considered solutions for towers with a standard cross-section of 1.75 m x 1.75 m, 2.5 m x 2.5 m is also shown. The use of slant panels with a reduced reflector as an alternative option for obtaining a radiation pattern unevenness acceptable for radio broadcasting is advisable in the case when mixed polarization is not a significant limitation for the broadcaster.

This paper delves into an interference analysis, focusing on the forthcoming Starlink Generation 2 satellites, stated to operate within the 1990-1995 MHz frequency band. The aim is to assess the potential interference from this Starlink system to the satellite receivers of mobile satellite systems (MSSs), which are set to function within the 1980-2010 MHz range, and satellite receivers of the NTN systems, which are planned to operate in the n256 bands, defined by the 3GPP specifications. Through simulation-based evaluations, both single-entry and aggregate interference levels from Starlink to MSSs and NTN systems are comprehensively explored. To estimate the interference impact, several protection criteria were used. The study is in line with the Recommendations of International Telecommunication Union (ITU-R) and common approaches that are used when performing compatibility studies between satellite systems. The findings of this study demonstrate the feasibility of utilizing the n25 band for NTN direct-to-device services.

With regard to location and navigation tasks for single-position passive observer, a bearing-free method for identifying parameters of a polynomial model of object motion has been developed taking into account evolution of the discrepancy between the periodic radiated and received quasi-periodic signal. The passage of a signal in an arbitrary physical environment is considered, at the same time, knowledge of the period of the emitted signal and assessing the current Doppler frequency are not required. The method is based on counting the number of periods of the received signal in a given surveillance intertissue. The issues related to the analysis of the resulting discrepancy by the observability of the method and its accuracy characteristics are considered. Useful practical recommendations and an illustrative context are given.

The methods for the artificial hydraulic structures condition monitoring using trace microwave radiometers are considered, in order to timely detect places of underground leaks to ensure trouble-free operation. Several practical examples of the use of microwave radiometers on various ground-based mobile carriers are described. The characteristics of microwave radiometers used in practice for hydrological monitoring of earthen dams are given. The possibility of detecting potentially dangerous sections of dams, places of erosion of the dam cover, possible places of underground leaks is shown. The possibility of combining microwave radiometers with other means of remote sensing, such as optical video cameras, thermal infrared cameras and georadars, is being considered. The advantages of multisensory sensing to increase the reliability of detecting places of underground leaks are substantiated.

Eliminating common-mode clutter in data is one of the key aspects of road sensing with GPR. Common-mode interference can occur as a result of multipath propagation of an electromagnetic signal when the reflected signal from the same object arrives at the receiver from different directions and with different delays. Similar phenomena also occur when using antennas raised above the surface due to multiple reflections between the air–surface interface and the antenna. These interferences can significantly distort the data received by the GPR and interfere with the accurate determination of the parameters of the roadway. Therefore, the elimination of common-mode clutter is an important task to improve the quality of the obtained results. In this paper, we consider a method for filtering common-mode clutter in the radar data of the multichannel GPR “Terrazond”, which were obtained by sounding a test section of a highway. The results obtained during filtering can then be used to determine the thickness of the pavement layers using approaches that take into account the signal delay determined by the amplitude jump, for example, the common point method or if the permittivity of each layer is known. The obtained thicknesses of pavement layers are compared with the results obtained during core drilling by the Russian Road Research Institute.

The problem of scattering of a plane electromagnetic wave by a 2D periodic structure formed by absorbing spherical radially inhomogeneous dielectric elements is considered. The elements have the type of electromagnetic black holes located on a semi-infinite substrate. The numerical algorithm of the solution is developed. The algorithm is based on the hybrid projection method and takes into account the peculiarities of the black hole construction. The algorithm is generalized to the case, when black holes are situated on a perfectly conducting screen. New expressions for calculating the power absorbed by the structure elements are derived. The numerical results characterizing the efficiency of the structure absorption are presented.

Современные рыночные условия заставляют производителей и продавцов искать новые пути продвижения своей продукции.Статья посвящена новым, возникшим в последнее время концепциям маркетинга, применяемым в международном бизнесе.Это концепции ноунейм маркетинг, ноомаркетинг и многоканальный маркетинг.Несмотря на различие концепций по своей сути, они направлены на повышение эффективности продвижения компаниями своих товаров или услуг.Ноунейм маркетинг представляет собой продвижение товаров неизвестных производителей