Перегляд за Автор "Kuznietsov, Oleksandr"
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Документ Evaluation of the possibilities of providing the necessary accuracy of the radial velocity measuring of a target by coherent-pulse radars outside the line of sight(Національний технічний університет "Харківський політехнічний інститут", 2019) Kuznietsov, Oleksandr; Karlov, Vladimir; Petrushenko, Valentin; Biesova, Oksana; Lukashuk, OlenaThe purpose of the article.The article estimates the possible values of the components of the mean-square error of measuring the radial velocity of the target which appear as a result of fluctuations of thephase of the radio signal outside the radar line of sight. The expediency of using a coherent burst of radio pulses to providethe necessary detection range with specified quality indicators is substantiated. Consideration is carried out for a model of a signal with a random amplitude and an initial phase. It is assumed that phase fluctuations are distributed according to the normal law with zero mean, and their correlation decreases with an increase in the interval between the radio bursts of the packet alternating. Results. The results show that due to the phase fluctuations of the radio pulses of the received pack, the mean-square measuring error of the target radial velocity can exceed the values determined by the tactical requirements for coherent-pulse radars. Conclusions.The performed numerical analysis allows to determine the degree of reductionof the quality of the radio pulses burst time-frequency processing in coherent-pulse radars and evaluates the degree of reduction of the effectiveness of the further secondary processing of the radar information.Документ The influence of statistical characteristics of the fluctuations of the radiation signal initial phases on the accuracy of the measurement aerodynamic object radial velocity(Національний технічний університет "Харківський політехнічний інститут", 2020) Kuznietsov, Oleksandr; Karlov, Vladimir; Kolomiitsev, Oleksii; Sadovyi, Kostiantyn; Biesova, OksanaThe article deals with the estimation of radial velocity when using a coherent packet of radio pulses regarding the case of the presence of correlated fluctuations of the initial phases in the reflected from the aerodynamic object pulses. The subject of the research is the accuracy of measuring the frequency of the received packet for the case of concerted processing without taking into account the phase fluctuations of its radio pulses. The purposeis a numerical analysis of the influence of the statistical characteristics of the fluctuations of the received pack’s initial phases on the decrease in the accuracy of measuring the radial velocity of the aerodynamic object. The task: to estimate the possible values of fluctuation constituent middling quadratic error of measuring of radial speed of aerodynamic object. Consideration is given to the assumption that an additive mixture of deflected signal and uncorrelated Gaussian noise is input to the radar receiver. It is considered that the phase fluctuations of the received packet are distributed according tothe normal law with zero mean, and the correlation of phase fluctuations with the increase of the interval between the packet radio pulses decreases according to the alternating law. Methods used: methods of probability theory and mathematical statistics. The following results are obtained: the accuracy of frequency measurement of the pack had been estimated in the presence of correlated phase fluctuations of its radio pulses. Conclusions. The results indicate that for modernradars in the conditions of regular measurement the accuracy of estimating the frequency of the packet of radio pulses is much more influenced by the statistical characteristics of the phase fluctuation than the signal-to-noise ratio. Due to the phase fluctuations of the radio pulses of the received packet, the mean-square error (MSE) of radial velocity measurement of the aerodynamic objectis able to exceed the values determined by the requirements for coherent pulse radar.Документ Proposals to improve the information capabilities of coastal-based radar stations for surveillance of surface and air objects(Національний технічний університет "Харківський політехнічний інститут", 2024) Kuznietsov, Oleksandr; Kolomiitsev, Oleksii; Nos, Ivan; Biesova, Oksana; Krykhovetskyi, HeorhiiSea-based radar stations (RS) are widely used for solving the tasks of radar surveillance of surface objects (SO) and air objects (AO). The subject of the article is the mechanisms of radio wave propagation in the boundary layer of the atmosphere. The aim is to investigate the possibilities of improving the accuracy of measuring the range and radial velocity of SO and AO observed beyond the line-of-sight of coastal-based RS. Objective: to analyse the spatial and temporal parameters and properties of waveguide layers above the water surface. Methods used: maximum likelihood and frequency. The following results were obtained. The results of experimental studies of seasonal and daily changes in the parameters of the lower troposphere layer in the Black Sea coastal zone and the parameters of tropospheric radio waveguides are presented. The procedure for calculating the energy transmission losses during radio wave propagation in the boundary layer of the atmosphere is presented, and the conditions for detecting SO and AO beyond the radar line-of-sight are determined. Recommendations for increasing the range of detection of SO and AO are given, which are associated with the possibility of predicting the existence of tropospheric radio waveguides by using data on the current conditions of radio wave propagation over the sea based on the signals of the automatic ship identification system AIS. Conclusions. Proposals have been developed to improve the accuracy of measuring the range and radial velocity of SO and AO at waveguide propagation of radio waves over the sea surface. A promising area for further research may be to identify ways to optimise the measurement of angular coordinates in modern RS during waveguide propagation of radio waves over the sea surface.