scholarly journals Information technologies for creating spatiotemporal modems multiposition active-passive radar systems

2021 ◽  
Vol 2094 (2) ◽  
pp. 022005
Author(s):  
A O Zhukov ◽  
E G Zhilyakov ◽  
I I Oleynik ◽  
S G Orishchuk ◽  
P A Fedorov ◽  
...  
Keyword(s):  
Antenna Arrays ◽  
Information Technologies ◽  
Spatial Uncertainty ◽  
Technological Problem ◽  
Coherent Signals ◽  
Spectral Correlation ◽  
Directional Diagram ◽  
Uncertainty Function ◽  
Spatio Temporal ◽  
Transmitting Antenna

Abstract The methods of synthesis of the directional diagram of active transmitting antenna arrays when receiving signals reflected from radar targets are considered. It is shown that when using multifrequency orthogonal coherent signals in the elements and addressable access at their reception it is possible to provide a small level of the side lobes of the spatial uncertainty function in a given sector of observation by selecting the type of intrapulse modulation of partial signals. Orthogonalization of antenna basis of transmitting and receiving antennas allows digital spectral-correlation processing of samples of aggregate signal from each target to solve the technological problem of multidimensional observation space in multiposition systems of coherent radiolocation when detecting, resolving, estimating coordinates and motion parameters of targets. The results of simulation modeling of spatio-temporal radar modems implemented according to the stated principles are given.

scholarly journals АЛГОРИТМЫ ПЕРВИЧНОЙ И ВТОРИЧНОЙ ОБРАБОТКИ СИГНАЛОВ В СИСТЕМАХ АКТИВНОГО АПЕРТУРНОГО СИНТЕЗА

2019 ◽  
pp. 54-67
Author(s):  
Владимир Владимирович Павликов ◽  
Валерий Константинович Волосюк ◽  
Ван Хиу Нгуен ◽  
Алексей Владимирович Одокиенко
Keyword(s):  
Image Quality ◽  
Imaging System ◽  
Block Diagram ◽  
Ambiguity Function ◽  
Physical Sense ◽  
Ideal Image ◽  
Uncertainty Function ◽  
Spatio Temporal ◽  
The Ideal

A method for processing spatio-temporal radio signals, which allows the formation of high spatial resolution images from aerospace carriers, has been synthesized. In this case, a swath is ±15° from the nadir relative to the flight line is considered. Traditionally this swath is not visible from aerospace carriers. A block diagram of an active-passive type radar is proposed. Initially the image obtained at the output of such a radar has a low quality of visual perception. Such image is called primary, since it was obtained at the stage of primary signal processing. The physical sense of such image is investigated. It approximately represents the operation of convolution of the ambiguity function with a spatial function proportional to the ideal image. The physical sense of the ideal image depends on the characteristics of the imaging system. In the problem under consideration, this is the specific radar cross section. In order to improve the quality of the image it is proposed additional processing (filtering). The paper substantiates the method of filtering (secondary processing) of images based on the solution of the inverse integral equation. It is shown that the exact solution to this equation is difficult to obtain because the form of the ambiguity function is not known exactly and can be estimated only approximately and, in addition, not for each ambiguity function it is possible to obtain a non-singular solution of the inversion equation. Therefore, an approximate solution to the problem is given. It solution is sufficient to solve practical problems of improving image quality. Using numerical simulation methods, the influence of the error in determining the shape of the uncertainty function on the task of improving image quality is studied. Examples of primary and secondary images obtained at the output of wideband active aperture synthesis systems with various geometries of spatially distributed antenna systems are given.

USE OF SPATIAL ANALYSIS TOOLS AND CAPABILITY OF GEOINFORMATION SYSTEMS FOR ASSESSMENT OF THE STATE OF UNDERGROUND WATERS

2020 ◽  
pp. 100-105
Author(s):  
О. Ostroukh ◽  
D. Chomko ◽  
V. Ostroukh ◽  
I. Pidlisetska
Keyword(s):  
Spatial Analysis ◽  
Chemical Composition ◽  
Information Technologies ◽  
Groundwater Resources ◽  
Integrated Approach ◽  
Temporal Changes ◽  
Geoinformation Systems ◽  
Underground Waters ◽  
Geographic Information Technologies ◽  
Spatio Temporal

The results of the study of the ecological-hydrogeochemical state of the underground waters of the Chop-Mukachevo basin and the identification of its spatio-temporal changes in the chemical composition using GIS facilities are presented. The methodology for processing the initial hydrogeological data on the basis of geographic information technologies has been improved and tested on the example of spatio-temporal changes in the indicators of chemical composition. A specialized geoinformation database of the chemical composition of groundwater has been created. The evaluation of spatio-temporal patterns of changes in the chemical composition using statistical analysis, cartographic modeling, and spatial analysis in GIS, identified areas with increased salinity and hardness of groundwater. Based on an integrated approach, zoning was performed and the current hydrogeochemical state of the groundwater resources of the study area was evaluated.

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