The Experts below are selected from a list of 114 Experts worldwide ranked by ideXlab platform
J. D. White - One of the best experts on this subject based on the ideXlab platform.
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GPS Application to Time Transfer and Dissemination
GPS Solutions, 1999Co-Authors: R. L. Beard, J. D. WhiteAbstract:The Global Positioning System (GPS), in addition to providing precise navigation and positioning information, produces precise Time and frequency measurements. These measurements result from the atomic clocks in the GPS satellites, which are closely coupled to Universal Coordinated Time as maintained by the U. S. Naval Observatory [UTC(USNO)]. The application of these measurements to Timekeeping and other systems requiring precise Time and frequency is distinct from the navigation/positioning mission. This article will describe the differences in application of GPS to Time and frequency uses. These uses will be described in the major areas of Timekeeping; stationary uses, such as communications networking; and mobile use for aircraft and shipboard applications. The major considerations in application and operation with precise and less-capable oscilators will be described. Examples and data will be presented to illustrate the applications. © 1999 John Wiley & Sons, Inc.
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Military Applications of Time and Frequency
1996Co-Authors: R. L. Beard, J. D. White, J A MurrayAbstract:Abstract : The introduction of the NAVSTAR Global Positioning System (GPS) to the military community is having an lesser known, but highly significant, impact on those systems requiring dissemination of precise Time and frequency. Precise Time/frequency and their uses could have a wider ranging influence on military electronic systems than the positioning/navigation aspects. The implications are not as well known or recognized. Time and Frequency (T/F) are a fundamental function needed by all military electronic equipment. From generation of frequencies for communications to remote sensing of geophysical quantities with Time-tagged data requires oscillators, T/F standards, and/or clocks. The application and requirements for these standards and their maintenance of them onto a common Timescale is a specialist's area open overlooked in the development and deployment of these systems, only to be addressed later as a operational problem area. The wide spectrum of applications and uses for timing devices within military systems can be categorized into different system types: (1) navigation, (2) communications, (3) identification, (4) remote sensing, (5) intelligence, and (6) weapons. In addition to using T/F devices and technology, military electronic systems are on diverse platforms, which operate most effectively in a highly Coordinated, interactive environment. This requires all units and elements of the operating forces to be referenced to the same Time. U.S. military systems are required to be referenced to Universal Coordinated Time (UTC) maintained by the U.S. Naval Observatory (USNO), designated UTC(USN0). From this central reference, Time is disseminated through various existing military and scientific systems. Navigation systems are the most immediate and well-known users of T/F, and from this fact are the primary systems used for T/F dissemination.
R. L. Beard - One of the best experts on this subject based on the ideXlab platform.
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GPS Application to Time Transfer and Dissemination
GPS Solutions, 1999Co-Authors: R. L. Beard, J. D. WhiteAbstract:The Global Positioning System (GPS), in addition to providing precise navigation and positioning information, produces precise Time and frequency measurements. These measurements result from the atomic clocks in the GPS satellites, which are closely coupled to Universal Coordinated Time as maintained by the U. S. Naval Observatory [UTC(USNO)]. The application of these measurements to Timekeeping and other systems requiring precise Time and frequency is distinct from the navigation/positioning mission. This article will describe the differences in application of GPS to Time and frequency uses. These uses will be described in the major areas of Timekeeping; stationary uses, such as communications networking; and mobile use for aircraft and shipboard applications. The major considerations in application and operation with precise and less-capable oscilators will be described. Examples and data will be presented to illustrate the applications. © 1999 John Wiley & Sons, Inc.
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Military Applications of Time and Frequency
1996Co-Authors: R. L. Beard, J. D. White, J A MurrayAbstract:Abstract : The introduction of the NAVSTAR Global Positioning System (GPS) to the military community is having an lesser known, but highly significant, impact on those systems requiring dissemination of precise Time and frequency. Precise Time/frequency and their uses could have a wider ranging influence on military electronic systems than the positioning/navigation aspects. The implications are not as well known or recognized. Time and Frequency (T/F) are a fundamental function needed by all military electronic equipment. From generation of frequencies for communications to remote sensing of geophysical quantities with Time-tagged data requires oscillators, T/F standards, and/or clocks. The application and requirements for these standards and their maintenance of them onto a common Timescale is a specialist's area open overlooked in the development and deployment of these systems, only to be addressed later as a operational problem area. The wide spectrum of applications and uses for timing devices within military systems can be categorized into different system types: (1) navigation, (2) communications, (3) identification, (4) remote sensing, (5) intelligence, and (6) weapons. In addition to using T/F devices and technology, military electronic systems are on diverse platforms, which operate most effectively in a highly Coordinated, interactive environment. This requires all units and elements of the operating forces to be referenced to the same Time. U.S. military systems are required to be referenced to Universal Coordinated Time (UTC) maintained by the U.S. Naval Observatory (USNO), designated UTC(USN0). From this central reference, Time is disseminated through various existing military and scientific systems. Navigation systems are the most immediate and well-known users of T/F, and from this fact are the primary systems used for T/F dissemination.
Andriy Dyukov - One of the best experts on this subject based on the ideXlab platform.
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Development of an Electronic Speed Measurement System for Evaluating the Accuracy of GNSS Receivers and Statistical Analysis of Their Performance in Speed Measurements
Universal Journal of Electrical and Electronic Engineering, 2016Co-Authors: Andriy DyukovAbstract:Global Navigation Satellite System (GNSS) receivers are now widely used for navigation and speed measurements. The majority of manufacturers of chipsets and receivers claim that their products are accurate to about 0.1 km/h in measuring speed. Therefore, it is a metrological challenge to test GNSS receivers in real world environments as test vehicles are generally not capable to provide such accuracy. The datasheets for GNSS receivers, however, provide no information about specific conditions when the claimed speed accuracy might be achieved. Limited practical research activities with traceable to national standards test vehicles were conducted to reveal the practical speed accuracy parameters of GNSS receivers in different conditions. This research firstly aims to design and implement an electronic system for a test vehicle which would generate speed records with high accuracy and traceability to national standards. High accuracy of the test vehicle and synchronization of its speed records with Universal Coordinated Time allowed conducting subsequent testing of GNSS receivers of different complexities for speed. Test results demonstrate that different GNSS receivers have different speed accuracy parameters both statistically and in regards to generation of outliers. GNSS environmental factors should be taken into consideration when relying on individual speed measurements.
S. M. Lichten - One of the best experts on this subject based on the ideXlab platform.
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Use of global positioning system measurements to determine geocentric coordinates and variations in Earth orientation
1993Co-Authors: R. P. Malla, S. M. LichtenAbstract:Geocentric tracking station coordinates and short-period Earth-orientation variations can be measured with Global Positioning System (GPS) measurements. Unless calibrated, geocentric coordinate errors and changes in Earth orientation can lead to significant deep-space tracking errors. Ground-based GPS estimates of daily and subdaily changes in Earth orientation presently show cenTimeter-level precision. Comparison between GPS-estimated Earth-rotation variations, which are the differences between Universal Time 1 and Universal Coordinated Time (UT1-UTC), and those calculated from ocean tide models suggests that observed subdaily variations in Earth rotation are dominated by oceanic tidal effects. Preliminary GPS estimates for the geocenter location (from a 3-week experiment) agree with independent satellite laser-ranging estimates to better than 10 cm. Covariance analysis predicts that temporal resolution of GPS estimates for Earth orientation and geocenter improves significantly when data collected from low Earth-orbiting satellites as well as from ground sites are combined. The low Earth GPS tracking data enhance the accuracy and resolution for measuring high-frequency global geodynamical signals over Time scales of less than 1 day.
Vijender Kumar Agrawal - One of the best experts on this subject based on the ideXlab platform.
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Energy savings from advancing the Indian Standard Time by half an hour
Current Science, 2007Co-Authors: Dilip R. Ahuja, Dp Sen Gupta, Vijender Kumar AgrawalAbstract:Since mechanical clocks were invented, three separate sequential adjustments have been made to Timekeeping - the adoption of mean Time, of Time zones incorporating standard Times, finally that of daylight saving Time (DST). India has accepted mean Times and a standard Time, but has resisted adopting Time zones or DST for several reasons. We propose advancing of the Indian Standard Time by half an hour to being six hours ahead of the Universal Coordinated Time. The primary benefit estimated from regional seasonal load curves is a saving in peak load electricity of nearly 16%. This is substantial given the difficulty most regions have in fulfilling the additional evening demand. There would be several other benefits that cannot be quantified easily.
