Pub Date : 2019-07-03DOI: 10.33955/2307-2180(3)2019.12-18
L. Kuzmych
Nowadays the most common instruments of measuring the stress-strain state of complex structures are strain gauges. As a rule, strain gages are connected to the measuring system according to the bridge scheme, it provides elimination of systematic errors of measurement and compensation of temperature deformations. The principles of constructing, designing and mathematical modeling of deformation and stresses of complex technical constructions with the help of strain gauges taking into account destabilizing factors are developed, which allows to significantly reduce the level of errors in relation to existing methods of measurement and known analogues. The analysis of the main destabilizing factors that limit the accuracy of measurement using strain gauge is carried out, are (Fig. 1—4): the random processes (noises, obstacles, etc.); the time changes of parameters of measuring transducers due to aging and physical degradation; the influence of external climatic and mechanical factors (temperature, humidity, etc.). The temperature error values are set for the most common alloys used for the manufacture of strain gauges, namely: constantan and karma. This work is aimed at finding ways to improve the accuracy of remote measurements and impedance of measuring devices of the stress — strain state, in particular strain gauges and strain gauges, by introducing improved theoretical calculations taking into account destabilizing factors, which makes it possible to reduce the level of errors with respect to known analogs in dozens of times.
{"title":"Synthesis of Measurement Method of Stressed — Deformed Condition of Complex Structures","authors":"L. Kuzmych","doi":"10.33955/2307-2180(3)2019.12-18","DOIUrl":"https://doi.org/10.33955/2307-2180(3)2019.12-18","url":null,"abstract":"Nowadays the most common instruments of measuring the stress-strain state of complex structures are strain gauges. As a rule, strain gages are connected to the measuring system according to the bridge scheme, it provides elimination of systematic errors of measurement and compensation of temperature deformations. The principles of constructing, designing and mathematical modeling of deformation and stresses of complex technical constructions with the help of strain gauges taking into account destabilizing factors are developed, which allows to significantly reduce the level of errors in relation to existing methods of measurement and known analogues. \u0000The analysis of the main destabilizing factors that limit the accuracy of measurement using strain gauge is carried out, are (Fig. 1—4): \u0000 \u0000the random processes (noises, obstacles, etc.); \u0000the time changes of parameters of measuring transducers due to aging and physical degradation; \u0000the influence of external climatic and mechanical factors (temperature, humidity, etc.). \u0000 \u0000The temperature error values are set for the most common alloys used for the manufacture of strain gauges, namely: constantan and karma. \u0000This work is aimed at finding ways to improve the accuracy of remote measurements and impedance of measuring devices of the stress — strain state, in particular strain gauges and strain gauges, by introducing improved theoretical calculations taking into account destabilizing factors, which makes it possible to reduce the level of errors with respect to known analogs in dozens of times.","PeriodicalId":52864,"journal":{"name":"Metrologiia ta priladi","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44599592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-03DOI: 10.33955/2307-2180(3)2019.55-60
R. Kozin, L. Kuznetsova, N. Hulyanytska, I. Mossokovska
Due to the expansion of the nomenclature of steel grades in the industry and the development of new special alloys with increased strength and corrosion-resistant properties, both in the metallurgical industry and in welding, researchers are very interested in the dissolution of nitrogen in metals and slag. Gas permeability of slag is one of the reasons for the appearance of gases in both the base metal and the weld metal. It is determined by two properties: solubility and mass transfer of gases in slag. In addition, in real conditions, the process of dissolving gases in slag is influenced by the transmission of gases by convection and the initial content of gases in the slag. The transfer of gases to the metal through slag is observed mainly in electroslag processes and welding under flux when there is no direct contact of molten metal with a gas phase. To evaluate the nitrogen permeability of the slag and the mechanism of nitrogen solubility in the high alloys it is necessary to have a reliable, highly sensitive and economical method of gas analysis of nitrogen in metals and slags. A review of nitrogen determination methods in steels is presented. The method of analysis of nitrogen in slags of the CaO — АL2O3 system by the Kjeldahl method was tested. The results of the analysis of slag compositions of the CaO — АL2O3 system allowed us to conclude that it is possible to use the Kjeldahl method (determination of nitrogen content in steels) for the determination of nitrogen content in slags. This technique and installation can be recommended for use by metallurgists and welders as a reliable, simple and inexpensive method for nitrogen content analysis in metals and slags.
{"title":"Determination of Nitrogen Content in the Slags of CaO — Al2O3 System by Kjeldahl Method","authors":"R. Kozin, L. Kuznetsova, N. Hulyanytska, I. Mossokovska","doi":"10.33955/2307-2180(3)2019.55-60","DOIUrl":"https://doi.org/10.33955/2307-2180(3)2019.55-60","url":null,"abstract":"Due to the expansion of the nomenclature of steel grades in the industry and the development of new special alloys with increased strength and corrosion-resistant properties, both in the metallurgical industry and in welding, researchers are very interested in the dissolution of nitrogen in metals and slag. Gas permeability of slag is one of the reasons for the appearance of gases in both the base metal and the weld metal. It is determined by two properties: solubility and mass transfer of gases in slag. In addition, in real conditions, the process of dissolving gases in slag is influenced by the transmission of gases by convection and the initial content of gases in the slag. The transfer of gases to the metal through slag is observed mainly in electroslag processes and welding under flux when there is no direct contact of molten metal with a gas phase. To evaluate the nitrogen permeability of the slag and the mechanism of nitrogen solubility in the high alloys it is necessary to have a reliable, highly sensitive and economical method of gas analysis of nitrogen in metals and slags. \u0000A review of nitrogen determination methods in steels is presented. The method of analysis of nitrogen in slags of the CaO — АL2O3 system by the Kjeldahl method was tested. The results of the analysis of slag compositions of the CaO — АL2O3 system allowed us to conclude that it is possible to use the Kjeldahl method (determination of nitrogen content in steels) for the determination of nitrogen content in slags. This technique and installation can be recommended for use by metallurgists and welders as a reliable, simple and inexpensive method for nitrogen content analysis in metals and slags.","PeriodicalId":52864,"journal":{"name":"Metrologiia ta priladi","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44823751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-03DOI: 10.33955/2307-2180(3)2019.4-11
O. Kupko
The situation with the metrological assurance of brightness measurements in Ukraine is analyzed. The main regulatory documents for the characterization of lux meters are considered. It was noted, that the components of the uncertainty of brightness due to the difference in the spectral composition of radiation, during calibration and measurement, as well as uncertainties due to spatial heterogeneity of the screens, are not fully considered. The characteristic values of these uncertainties are calculated by the method of mathematical modeling, using generally accepted calculation methods. To calculate the spectral errors, the literature data on the spectra of CCFL and LED monitors were used, as well as the modeling of the spectra of blue, green and red radiation sources, using Gaussian distribution with varying widths. It is shown, that for а brightness meter calibrated by а type A source, the use of white screens for measuring the brightness will result in errors, less than 7%. It is shown, that when calibrating the brightness meter using the CCFL screen and then using the LED for the screen, the errors will be about 1%. Simple formulas are given to evaluate the effect of screen heterogeneity. For а refined assessment of the influence of spatial inhomogeneity, mathematical modeling was carried out — 3 types of brightness distribution, were used with decreasing radiation distribution density and two types of viewing area — а circle (imitation of brightness measurement, using а diaphragm) and а Gaussian distribution (imitation of brightness measurement with а lens) equal widths. It is shown, that for the field of sight in the form of а Gaussian distribution, the influence of the inhomogeneity of the distribution of screen illumination, when moving and changing the width of the field of sight is insignificant. Two approaches have been proposed for building the material base for metrological assurance of brightness measurements.
{"title":"Features of measuring the brightness of the screens","authors":"O. Kupko","doi":"10.33955/2307-2180(3)2019.4-11","DOIUrl":"https://doi.org/10.33955/2307-2180(3)2019.4-11","url":null,"abstract":"The situation with the metrological assurance of brightness measurements in Ukraine is analyzed. The main regulatory documents for the characterization of lux meters are considered. It was noted, that the components of the uncertainty of brightness due to the difference in the spectral composition of radiation, during calibration and measurement, as well as uncertainties due to spatial heterogeneity of the screens, are not fully considered. The characteristic values of these uncertainties are calculated by the method of mathematical modeling, using generally accepted calculation methods. To calculate the spectral errors, the literature data on the spectra of CCFL and LED monitors were used, as well as the modeling of the spectra of blue, green and red radiation sources, using Gaussian distribution with varying widths. It is shown, that for а brightness meter calibrated by а type A source, the use of white screens for measuring the brightness will result in errors, less than 7%. It is shown, that when calibrating the brightness meter using the CCFL screen and then using the LED for the screen, the errors will be about 1%. Simple formulas are given to evaluate the effect of screen heterogeneity. For а refined assessment of the influence of spatial inhomogeneity, mathematical modeling was carried out — 3 types of brightness distribution, were used with decreasing radiation distribution density and two types of viewing area — а circle (imitation of brightness measurement, using а diaphragm) and а Gaussian distribution (imitation of brightness measurement with а lens) equal widths. It is shown, that for the field of sight in the form of а Gaussian distribution, the influence of the inhomogeneity of the distribution of screen illumination, when moving and changing the width of the field of sight is insignificant. Two approaches have been proposed for building the material base for metrological assurance of brightness measurements.","PeriodicalId":52864,"journal":{"name":"Metrologiia ta priladi","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47304018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-03DOI: 10.33955/2307-2180(3)2019.27-32
E. Volodarskyi, A. Voloshko
The saturation of power supply systems with nonlinear and powerful sources both from sources and consumers of electricity has led to the fact that signals in the network become non-stationary, nonlinear, and with significant frequency fluctuations. The purpose of the work is to reduce the methodological error of determining the parameters of the mode of electricity consumption due to the frequency deviation in the electrical network. The article proposes methods based on the determination of the frequency deviation value and the introduction of correction coefficients (for example, the calculation of active power and voltage in the electric network). The proposed methods are applied to both sinusoidal and non-sinusoidal signal forms. The results show that these methods have high accuracy, even with signals containing harmonics, and for a frequency deviating from the nominal value.
{"title":"Correction for the deviation of power system frequency in the measurement of power by digital techniques","authors":"E. Volodarskyi, A. Voloshko","doi":"10.33955/2307-2180(3)2019.27-32","DOIUrl":"https://doi.org/10.33955/2307-2180(3)2019.27-32","url":null,"abstract":"The saturation of power supply systems with nonlinear and powerful sources both from sources and consumers of electricity has led to the fact that signals in the network become non-stationary, nonlinear, and with significant frequency fluctuations. The purpose of the work is to reduce the methodological error of determining the parameters of the mode of electricity consumption due to the frequency deviation in the electrical network. The article proposes methods based on the determination of the frequency deviation value and the introduction of correction coefficients (for example, the calculation of active power and voltage in the electric network). The proposed methods are applied to both sinusoidal and non-sinusoidal signal forms. The results show that these methods have high accuracy, even with signals containing harmonics, and for a frequency deviating from the nominal value.","PeriodicalId":52864,"journal":{"name":"Metrologiia ta priladi","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43124464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-03DOI: 10.33955/2307-2180(3)2019.67-71
K. Kushnir
Розглянуто стан забезпечення єдності вимірювань під час надання населенню медичних послуг новоутвореними центрами первинноїмедико-санітарноїдопомоги, описано проблеми, які на практиці виникають з метрологічним забезпеченням їх діяльності та запропоновано шляхи вирішення цих проблем.
{"title":"Problems of Metrological Provision of Activities of Primary Medical-Sanitary Assistance Bodies","authors":"K. Kushnir","doi":"10.33955/2307-2180(3)2019.67-71","DOIUrl":"https://doi.org/10.33955/2307-2180(3)2019.67-71","url":null,"abstract":"Розглянуто стан забезпечення єдності вимірювань під час надання населенню медичних послуг новоутвореними центрами первинноїмедико-санітарноїдопомоги, описано проблеми, які на практиці виникають з метрологічним забезпеченням їх діяльності та запропоновано шляхи вирішення цих проблем.","PeriodicalId":52864,"journal":{"name":"Metrologiia ta priladi","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45437687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-05-03DOI: 10.33955/2307-2180(2)2019.57-61
E. Koretsky, S. Shevkun, M. Golovnya, O. Mesheryak, V. Bojko, A. Gavrilov, M. Svitenko, M. Trotsko
Within the limits of the functioning of the military segment of the single time service and reference frequencies, the problems and ways of solving the tasks of controlling and controlling the transmission of reference signals used by the Armed Forces of Ukraine are outlined. The experimental research on the determination of the accuracy characteristics of the time synchronization system (using the PTP protocol IEEE 1588v2) was implemented for its use in telecommunication networks. As a communication channel, an optical fiber network is specially built to create a synchronization system. Experimental studies confirmed the possibility of transmitting reference signals of time and frequency synchronization with the use of modern digital and fiber-optic technologies from the National Standard of Time and Frequency units to the source standard of the Armed Forces of Ukraine units of time and frequency (VEZSU) with an error that is not exceeds 1 цs And also from VESZU to consumers with an error of less than 10 microseconds at a distance of 600 km via fiber-optic communication channel L2. The creation of a corresponding complex of equipment for monitoring and control of the transmission of reference signals used by the Armed Forces of Ukraine remains relevant.
{"title":"Problems and Ways to take Objectives with the Control and Management by the Transmission of Ethnic Time and Frequency Signals in the Armed Forces of Ukraine","authors":"E. Koretsky, S. Shevkun, M. Golovnya, O. Mesheryak, V. Bojko, A. Gavrilov, M. Svitenko, M. Trotsko","doi":"10.33955/2307-2180(2)2019.57-61","DOIUrl":"https://doi.org/10.33955/2307-2180(2)2019.57-61","url":null,"abstract":"Within the limits of the functioning of the military segment of the single time service and reference frequencies, the problems and ways of solving the tasks of controlling and controlling the transmission of reference signals used by the Armed Forces of Ukraine are outlined. The experimental research on the determination of the accuracy characteristics of the time synchronization system (using the PTP protocol IEEE 1588v2) was implemented for its use in telecommunication networks. As a communication channel, an optical fiber network is specially built to create a synchronization system. Experimental studies confirmed the possibility of transmitting reference signals of time and frequency synchronization with the use of modern digital and fiber-optic technologies from the National Standard of Time and Frequency units to the source standard of the Armed Forces of Ukraine units of time and frequency (VEZSU) with an error that is not exceeds 1 цs And also from VESZU to consumers with an error of less than 10 microseconds at a distance of 600 km via fiber-optic communication channel L2. The creation of a corresponding complex of equipment for monitoring and control of the transmission of reference signals used by the Armed Forces of Ukraine remains relevant.","PeriodicalId":52864,"journal":{"name":"Metrologiia ta priladi","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44182923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-05-03DOI: 10.33955/2307-2180(2)2019.11-15
O. Velychko, S. Shevkun, O. Meshcheriak, M. Dobroliubova
The method of calibration of plants for verification of stopwatches with the help of the electronic-counting CNT-90 frequency meter is presented. The measurement circuits for verification (calibration) of reference plants for verification (calibration) of stopwatches are given. The device for synchronous start, which is based on the transformation of the motion signal of the moving part of the plant into an electrical signal of direct current using optical sensors, is used in the measuring circuit for calibration plants of mechanical stopwatches, and, the device for synchronous start, which is based on the transformation of the audio signal of an electronic stopwatch into an electrical signal of direct current using microphone, is used in the measuring circuit for calibration plants of electronic stopwatches. An example of the applying of the CNT-90 electronic frequency counter software is provided, which allows you to calculate the verification and calibration results (rejections the measurements of time and instability indexes) in the automatic mode. The calibration model and uncertainty budget for calibration of stopwatches are presented. The components of Type A and B, in accordance with calibration model are recorded when calculating the combined standard uncertainty in the form of standard uncertainties. The components of Type B: standard uncertainty due to the electronic counting frequency meter readings from the nominal value is taken from the calibration certificate of the frequency meter; standard uncertainty due to the drift of an electron-counting frequency meter since its last calibration; standard uncertainty due to the discreteness of indications of the plant indicator; standard uncertainty due to the effect of the device for synchronous start. The method of verification and calibration of installations for verification (calibration) of stopwatches, which are describe in the article, can be used in scientific metrological institutions, state enterprises, metrological services of state bodies, by enterprises and organizations, conformity assessment bodies of measuring instruments and in any other laboratories which have appropriate equipment and required standards.
{"title":"Calibration of the Plants for Verification of Stopwatchs","authors":"O. Velychko, S. Shevkun, O. Meshcheriak, M. Dobroliubova","doi":"10.33955/2307-2180(2)2019.11-15","DOIUrl":"https://doi.org/10.33955/2307-2180(2)2019.11-15","url":null,"abstract":"The method of calibration of plants for verification of stopwatches with the help of the electronic-counting CNT-90 frequency meter is presented. The measurement circuits for verification (calibration) of reference plants for verification (calibration) of stopwatches are given. The device for synchronous start, which is based on the transformation of the motion signal of the moving part of the plant into an electrical signal of direct current using optical sensors, is used in the measuring circuit for calibration plants of mechanical stopwatches, and, the device for synchronous start, which is based on the transformation of the audio signal of an electronic stopwatch into an electrical signal of direct current using microphone, is used in the measuring circuit for calibration plants of electronic stopwatches. \u0000An example of the applying of the CNT-90 electronic frequency counter software is provided, which allows you to calculate the verification and calibration results (rejections the measurements of time and instability indexes) in the automatic mode. The calibration model and uncertainty budget for calibration of stopwatches are presented. The components of Type A and B, in accordance with calibration model are recorded when calculating the combined standard uncertainty in the form of standard uncertainties. \u0000The components of Type B: \u0000 \u0000standard uncertainty due to the electronic counting frequency meter readings from the nominal value is taken from the calibration certificate of the frequency meter; \u0000standard uncertainty due to the drift of an electron-counting frequency meter since its last calibration; \u0000standard uncertainty due to the discreteness of indications of the plant indicator; \u0000standard uncertainty due to the effect of the device for synchronous start. \u0000 \u0000The method of verification and calibration of installations for verification (calibration) of stopwatches, which are describe in the article, can be used in scientific metrological institutions, state enterprises, metrological services of state bodies, by enterprises and organizations, conformity assessment bodies of measuring instruments and in any other laboratories which have appropriate equipment and required standards.","PeriodicalId":52864,"journal":{"name":"Metrologiia ta priladi","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46429429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-05-03DOI: 10.33955/2307-2180(2)2019.62-66
G. Baranov, R. Gabruk, I. Gorishna
In this paper, we analyzed the features of Doppler processing in radars. In ground based radars, the amount of clutter in the radar receiver depends heavily on the radar-to-target geometry. The amount clutter is considerably higher when the radar beam has to face toward the ground. Furthermore, radars employing high PRFs have to deal with an increased amount of clutter due to folding in range. Clutter introduces additional difficulties for airborne radars when detecting ground targets and other targets flying at low altitudes. This is illustrated in Fig. 10.5. Returns from ground clutter emanate from ranges equal to the radar altitude to those which exceed the slant range along the main-beam, with considerable clutter returns in the side-lobes and main-beam. The presence of such large amounts of clutter interferes with radar detection capabilities and makes it extremely difficult to detect targets in the look-down mode. This difficulty in detecting ground or low altitude targets has led to the development of pulse Doppler radars where other targets, kinematics such as Doppler effects are exploited to enhance detection. Pulse Doppler radars utilize high PRFs to increases the average transmitted power and rely on target's Doppler frequency for detection. The increase in the average transmitted power leads to an improved SNR which helps the detection process. However, using high PRFs compromise the radar's ability to detect long range target because of range ambiguities associated with high PRF applications. Techniques such as using specialized Doppler filters to reject clutter are very effective and are often employed by pulse Doppler radars. Pulse Doppler radars can measure target Doppler frequency (or its range rate) fairly accurately and use the fact that ground clutter typically possesses limited Doppler shift when compared with moving targets to separate the two returns. Clutter filtering is used to remove both main-beam and altitude clutter returns, and fast moving target detection is done effectively by exploiting its Doppler frequency. In many modern pulse Doppler radars the limiting factor in detecting slow moving targets is not clutter but rather another source of noise referred to as phase noise generated from the receiver local oscillator instabilities.
{"title":"Features of Usіng Pulse-Doppler Radars for Determіnatіon Low-Altіtude Targets","authors":"G. Baranov, R. Gabruk, I. Gorishna","doi":"10.33955/2307-2180(2)2019.62-66","DOIUrl":"https://doi.org/10.33955/2307-2180(2)2019.62-66","url":null,"abstract":"In this paper, we analyzed the features of Doppler processing in radars. In ground based radars, the amount of clutter in the radar receiver depends heavily on the radar-to-target geometry. The amount clutter is considerably higher when the radar beam has to face toward the ground. Furthermore, radars employing high PRFs have to deal with an increased amount of clutter due to folding in range. Clutter introduces additional difficulties for airborne radars when detecting ground targets and other targets flying at low altitudes. This is illustrated in Fig. 10.5. Returns from ground clutter emanate from ranges equal to the radar altitude to those which exceed the slant range along the main-beam, with considerable clutter returns in the side-lobes and main-beam. The presence of such large amounts of clutter interferes with radar detection capabilities and makes it extremely difficult to detect targets in the look-down mode. This difficulty in detecting ground or low altitude targets has led to the development of pulse Doppler radars where other targets, kinematics such as Doppler effects are exploited to enhance detection. Pulse Doppler radars utilize high PRFs to increases the average transmitted power and rely on target's Doppler frequency for detection. The increase in the average transmitted power leads to an improved SNR which helps the detection process. However, using high PRFs compromise the radar's ability to detect long range target because of range ambiguities associated with high PRF applications. \u0000Techniques such as using specialized Doppler filters to reject clutter are very effective and are often employed by pulse Doppler radars. Pulse Doppler radars can measure target Doppler frequency (or its range rate) fairly accurately and use the fact that ground clutter typically possesses limited Doppler shift when compared with moving targets to separate the two returns. Clutter filtering is used to remove both main-beam and altitude clutter returns, and fast moving target detection is done effectively by exploiting its Doppler frequency. In many modern pulse Doppler radars the limiting factor in detecting slow moving targets is not clutter but rather another source of noise referred to as phase noise generated from the receiver local oscillator instabilities. \u0000 ","PeriodicalId":52864,"journal":{"name":"Metrologiia ta priladi","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45958990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-05-03DOI: 10.33955/2307-2180(2)2019.36-42
V. Ignatkin
The article discusses metrological reliability of measuring equipment (ME), argues that ME imprecision must be considered not in statics, 'out in dynamics, taking into account the change of its characteristics over time. Measurement imprecision and its components are considered as random processes that are fully characterized by multidimensional distribution. It is advisable to determine the probability of metrological measurements directly from the experiment due to the difficulties of analytical solution to the problem. The characteristics of dynamic imprecision depend on both the values of the measured object and the ME properties. The physical cause of dynamic imprecision taking place is inertia of ME, its exhaustive description relies on the use of Duamel integral, which determines the response of inertial link to the input influence. As a criterion for signal differences one can use quite different functionals, taking into account further use of measurement results, the convenience of computing, the properties or input influences, and so on. It is most expedient to use the dispersion of signal differences. To calculate the parameters of dynamic imprecision it is necessary to know the energy spectrum of the input signal. The given ratios can be used for both stationary and non-stationary processes. The paper provides examples of using these ratios, recommendations for reducing measurement errors in each particular case.
{"title":"Features of Dynamic Error Analysis in the Process of Evaluation of Metrological Reliability of Measuring Equipment","authors":"V. Ignatkin","doi":"10.33955/2307-2180(2)2019.36-42","DOIUrl":"https://doi.org/10.33955/2307-2180(2)2019.36-42","url":null,"abstract":"The article discusses metrological reliability of measuring equipment (ME), argues that ME imprecision must be considered not in statics, 'out in dynamics, taking into account the change of its characteristics over time. Measurement imprecision and its components are considered as random processes that are fully characterized by multidimensional distribution. It is advisable to determine the probability of metrological measurements directly from the experiment due to the difficulties of analytical solution to the problem. The characteristics of dynamic imprecision depend on both the values of the measured object and the ME properties. The physical cause of dynamic imprecision taking place is inertia of ME, its exhaustive description relies on the use of Duamel integral, which determines the response of inertial link to the input influence. As a criterion for signal differences one can use quite different functionals, taking into account further use of measurement results, the convenience of computing, the properties or input influences, and so on. It is most expedient to use the dispersion of signal differences. To calculate the parameters of dynamic imprecision it is necessary to know the energy spectrum of the input signal. The given ratios can be used for both stationary and non-stationary processes. \u0000The paper provides examples of using these ratios, recommendations for reducing measurement errors in each particular case.","PeriodicalId":52864,"journal":{"name":"Metrologiia ta priladi","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44336054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-05-03DOI: 10.33955/2307-2180(2)2019.43-51
Y. Stentsel, O. Porkuian, K. Litvinov, T. Sotnikova
Studies have shown that under industrial conditions there is rarely a correction of the current measurement result when the influencing parameter deviates from the normalized value. The existing method of determining the additional measurement error is that in order to obtain the real value of the measurement result, the correction is calculated, which leads to the current value of indexes of control means. The correction value is determined by dividing the degree of the influencing parameter deviation by the normalized value of the additional error. This method of determining the correction is not accurate enough, since it does not take into account the nonlinear dependence of the additional measurement error on the change in the influencing parameter, as well as on the current value of the output signal of control means. To determine the real value of the measured parameter and the additional error, the method of integral-type functional is proposed. The essence of the method is in determining the difference of planes under the nominal and current parts of the static characteristic, limited by the measurement range. It is shown that the planes difference depends on the current and real values of the output signal of control means, as well as on the influencing parameter deviation. The method allows calculating the real values of the measured parameter only by the output signal of control means and the current values of the influencing parameter. The dependencies between the real value of the measured parameter, the current value of the output signal of control means and the influencing parameter deviation are established.
{"title":"Mathematical Models of Additional Measurement Errors of Control Means","authors":"Y. Stentsel, O. Porkuian, K. Litvinov, T. Sotnikova","doi":"10.33955/2307-2180(2)2019.43-51","DOIUrl":"https://doi.org/10.33955/2307-2180(2)2019.43-51","url":null,"abstract":"Studies have shown that under industrial conditions there is rarely a correction of the current measurement result when the influencing parameter deviates from the normalized value. The existing method of determining the additional measurement error is that in order to obtain the real value of the measurement result, the correction is calculated, which leads to the current value of indexes of control means. The correction value is determined by dividing the degree of the influencing parameter deviation by the normalized value of the additional error. This method of determining the correction is not accurate enough, since it does not take into account the nonlinear dependence of the additional measurement error on the change in the influencing parameter, as well as on the current value of the output signal of control means. To determine the real value of the measured parameter and the additional error, the method of integral-type functional is proposed. The essence of the method is in determining the difference of planes under the nominal and current parts of the static characteristic, limited by the measurement range. It is shown that the planes difference depends on the current and real values of the output signal of control means, as well as on the influencing parameter deviation. The method allows calculating the real values of the measured parameter only by the output signal of control means and the current values of the influencing parameter. The dependencies between the real value of the measured parameter, the current value of the output signal of control means and the influencing parameter deviation are established.","PeriodicalId":52864,"journal":{"name":"Metrologiia ta priladi","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46497627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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