Forecasting the radiation background in the territories of Kazakhstan located near the uranium mining industries

A significant part of the territory of Kazakhstan is characterized by a high natural background radiation of soils and rocks, the spread of natural ground and underground waters with high concentrations of radionuclides in the regions of uranium, thorium and rare metal ore provinces and regions. Therefore, conducting high-quality radio monitoring of the state of the environment using modern information systems will make it possible to predict the background radiation in a timely manner and outline measures to reduce environmental risks to the health of the nation as a whole. Key words: radioecology, monitoring, life safety, radionuclides, national health.

Ways to identify bearings in two-position goniometric airborne radiomonitoring systems.

For aeronautical goniometric systems for radio monitoring of radio emission sources (RES), one of the primary tasks is the identification of bearings. It is especially difficult to solve the problem of identifying bearings if there are several RESs in the observation area in the case when they are located in the same plane with the direction finders. In this case, the problem of identifying bearings in goniometric two-position systems is solved in the process of performing a two-stage procedure. At the first stage, the primary identification of single measurements of bearings is carried out separately at each receiving position (RP) when receiving radio signals from the RES, and at the second stage, the secondary (inter-positional) identification of bearings arriving from both RPs is carried out. In the initial identification, strobe and strobeless identification algorithms are used. In the secondary identification for selection of true and false points of intersection of bearings on the plane, it is proposed to use the kinematic parameters of the relative RES. However, this type of selection does not provide interposition identification with an arbitrary nature of the movement of the RES relative to the RP, and also assumes a constant angular position of the RP base on the plane. More practical are ways of identifying bearings with RES, in which the procedure for constructing a confidence region (CR) in the form of a circle with a certain radius is used. However, a more correct form of CR is an elliptical CR, since the errors in determining the position of the RES are characterized by an error ellipse, a particular case of which is a circle. Therefore, methods for identifying coordinate information have been developed, in which elliptical CRs are used. In this case, not only the bearings of the RES, but also other measured parameters, for example, estimates of the rectangular coordinates of the RES, calculated on the basis of the triangulation method, can be used as coordinate information. The purpose of the article is to systematize and analyze the developed methods for identifying bearings, which allow one to get a fairly general idea of how to solve the problem of identifying bearings and indirect measurements of the coordinates of radio emission sources in aviation goniometric two-position radio monitoring systems. As a result, a classification of identification methods is given. The existing possibilities and limitations of using various identification methods in solving radio monitoring problems are analyzed. The necessary information on the methods and algorithms for interpositional identification of coordinate information about the position of the RES, using ellipsoidal CRs in solving the identification problem, is given. The practical significance of the presented methods is to increase the likelihood of correct identification of coordinate information, as well as the accuracy of the positioning of RES due to the use of elliptical CRs, which more accurately reflect the regularity of the distribution of errors in determining the position of RES.

Digital demodulators for analog signals: comparative analysis and simulation

The paper examines digital demodulators for two commonly used techniques of modulating analog signals: amplitude modulation (AM) and frequency modulation (FM). The described demodulators can be used to perform the radio monitoring of narrowband signal ranges including FM broadcasting stations as well as license-free CB, LPD, PMR bands. The demodulators considered in this work are intended for programmable devices with limited memory and computing resources, for example, for STM32F407 microcontrollers and similar ones. The paper presents the analysis and simulation of demodulators for AM signals, FM signals with low modulation indices and for FM signals without restriction on the modulation indices. In addition, the authors demonstrate how to demodulate the phase-modulation signal using a quadrature demodulator. The number of operations that are available for demodulation is limited by IF multiplication and filtering. The simulation of the analyzed demodulation algorithms was carried out in the Scilab environment which is a free analogue of the Matlab environment. To explain the principle of operation of demodulators, block diagrams and graphs of signals in time and frequency domains are shown.

Prospect for Using Low-Element Adaptive Antenna Systems for Radio Monitoring Stations

This article is devoted to the analysis of prospect to apply multifunctional adaptive antenna systems for radio monitoring stations. The review of publications done demonstrates that current antennas that are developed and used in radio monitoring systems to control and measure the parameters of electromagnetic radiation should be applicable to conduct accurate measurements in wide frequency range under the condition of interferences. The analysis shows that modern adaptive antenna systems are mostly developed for radar and telecommunications applications. In this context we consider possible ways to solve the problem of adapting radio monitoring devices to a complex electromagnetic environment using antenna systems with primary processing of received signals . It was found that the developers of the antennas, which are based on adaptive interference suppression methods, focus basically on the development and implementation of adaptation processes, limiting themselves only to solving electromagnetic compatibility problems. In such approach, the functions of direction finding and measurement of radiation field parameters important exactly for radio monitoring systems are mostly ignored. Therefore, this research area opens up a wide field for identifying new possibilities for constructing multifunctional antenna systems. Focusing on this direction of research, we consider as an example the constraction of a simple two-element adaptive antenna system, which can be used to measure the parameters of the electromagnetic field in radio monitoring systems. The main relations for the error of determining the direction of arrival of the interference signal with a simple two-element antenna are investigated. The influence of the stability of the antenna array parameters and functional units of signal processing onto the errors is estimated.

Research on the Minimum Size of Received Signal Strength Difference Localization Network

The received signal strength difference (RSSD) localization is a kind of method to locate emission sources by measuring the differences of received signal strength level between the monitoring stations and is essentially the truth value ratios of measured signal strength. In the existing literatures, only the rule of RSSD localization circle of two monitoring stations and the geometric relation of RSSD localization circle of five monitoring stations were analyzed, but the number and the station layout of the minimum RSSD localization network have not been investigated. In the present work, first, based on the existing RSSD localization equation, the constants of the commonly used wave propagation models are provided. Then, the minimum RSSD localization network is proved through algebraic analysis, which is that four monitoring stations not distributed on a straight line can locate the signal source at one point. The relationship between the localization accuracy and the signal strength error of the RSSD location network with different scales is studied further and formulated as a nonlinear programming optimization problem. It is found that the localization stability of the network with four stations is poor, and there is a serious localization deviation outlier phenomenon. Therefore, the network with four stations is not available for radio monitoring networks with a signal strength error of ± 5 to ± 10 dB. The RSSD network with five stations is basically the minimum available size, and the RSSD network with nine stations can approach the localization accuracy of the angle of arrival (AOA) network with three stations.

Generalizing the sampling theorem for a frequency-time domain to sample signals under the conditions of a priori uncertainty

The radio monitoring of radiation and interference with electronic means is characterized by the issue related to the structural-parametric a priori uncertainty about the type and parameters of the ensemble of signals by radio-emitting sources. Given this, it is a relevant task to devise a technique for the mathematical notation of signals in order to implement their processing, overcoming their a priori uncertainty in terms of form and parameters. A given problem has been solved by the method of generalization and proof for the finite signals of the Whittaker-Kotelnikov-Shannon sampling theorem (WKS) in the frequency-time domain. The result of proving it is a new discrete frequency-temporal description of an arbitrary finite signal in the form of expansion into a double series on the orthogonal functions such as sinx/x, or rectangular Woodward strobe functions, with an explicit form of the phase-frequency-temporal modulation function. The properties of the sampling theorem in the frequency-time domain have been substantiated. These properties establish that the basis of the frequency-time representation is orthogonal, the accuracy of approximation by the basic functions sinx/x and rectangular Woodward strobe functions are the same, and correspond to the accuracy of the UCS theorem approximation, while the number of reference points of an arbitrary, limited in the width of the spectrum and duration, signal, now taken by frequency and time, is determined by the signal base. The devised description of signals in the frequency-time domain has been experimentally investigated using the detection-recovery of continuous, simple pulse, and linear-frequency-modulated (LFM) radio signals. The constructive nature of the resulting description has been confirmed, which is important and useful when devising methods, procedures, and algorithms for processing signals under the conditions of structural-parametric a priori uncertainty.

Methods of Determination of Optimal Points of Radio Monitoring Means Placement

The effectiveness of the radio monitoring system depends on the correctness of determining the coordinates of the location of radio monitoring tools at the stage of planning their application. The decision on the choice of position for radio monitoring should consider the heterogeneity of the terrain in the area of tasks, the presence of natural and electronic interference, which can lead to deterioration of conditions for receiving signals from radio sources. The use of the known methods, techniques, and algorithms for the placement of radio monitoring tools does not fully consider the requirements mentioned above. This leads to a decrease in the effectiveness of radio monitoring in a particular area of performance. Therefore, the purpose of this article is to develop a methodology for spatial placement of radio monitoring to ensure the effectiveness of radio monitoring in a particular area of tasks, taking into account the heterogeneity of the terrain, as well as natural and artificial electronic interference. Determining the coordinates of radio monitoring facilities included in the radio monitoring system involves determining the allowable options for their placement in a particular area of tasks using the mathematical apparatus of the dense placement function and its hodograph and further thinning of the matrix of acceptable solutions based on restrictions. A distinctive feature of the proposed approach is the optimization problem of geometric design for radio monitoring of complex spatial forms. At the same time, the peculiarities of completing the radio monitoring system using different types are also taken into account. It is expedient to use the developed technique for the planning of application of the system of radio monitoring; formation of working decisions on the construction of the radio monitoring system; assessing the quality of decisions and the formation of alternatives; ensuring the adaptation of the structure of the radio monitoring system to changes in the situation under the influence of the enemy and the formation of new zones of electronic interference.

Cellular Network Radio Monitoring and Management through Virtual UE Probes: A Study Case Based on Crowded Events

Although log processing of network equipment is a common technique in cellular network management, several factors make said task challenging, especially during mass attendance events. The present paper assesses classic methods for cellular network measurement and acquisition, showing how the use of on-the-field user probes can provide relevant capabilities to the analysis of cellular network performance. Therefore, a framework for the deployment of this kind of system is proposed here based on the development of a new hardware virtualization platform with radio frequency capabilities. Accordingly, an analysis of the characteristics and requirements for the use of virtual probes was performed. Moreover, the impact that social events (e.g., sports matches) may have on the service provision was evaluated through a real cellular scenario. For this purpose, a long-term measurement study during crowded events (i.e., football matches) in a stadium has been conducted, and the performances of different services and operators under realistic settings has been evaluated. As a result, several considerations are presented that can be used for better management of future networks.