Development of a Microwave Modulated, Dual Optical Wavelength Geodetic Distance-measuring Instrument PDF Download
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Author: J. C. Owens
Publisher:
ISBN:
Category : Geodesy
Languages : en
Pages : 200
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Book Description
The accuracy of optical distance measurements on horizontal paths is limited at present to several parts per million by uncertainty in knowledge of the average air density along the path. This report describes the development and testing of a prototype instrument capable of significant;y greater accuracy, probably as high as 0.1 ppm. The instrument makes simultaneous measurements of transit time using two superimposed beams of light which have different optical wavelengths but which are modulated at a common microwave frequency. From the difference in transit times for the two colors, plus the absolute transit for either one, the average refractive index along the path and hence the true geodetic path length can be determined. Tests over a 5.3 -km patch have given a standard error of 0.3 ppm in corrected distance, and it is believed that even better results can be obtained. The system is described in detail, including modifications that would significantly increase its accuracy and range.
Author: J. C. Owens
Publisher:
ISBN:
Category : Geodesy
Languages : en
Pages : 200
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Book Description
The accuracy of optical distance measurements on horizontal paths is limited at present to several parts per million by uncertainty in knowledge of the average air density along the path. This report describes the development and testing of a prototype instrument capable of significant;y greater accuracy, probably as high as 0.1 ppm. The instrument makes simultaneous measurements of transit time using two superimposed beams of light which have different optical wavelengths but which are modulated at a common microwave frequency. From the difference in transit times for the two colors, plus the absolute transit for either one, the average refractive index along the path and hence the true geodetic path length can be determined. Tests over a 5.3 -km patch have given a standard error of 0.3 ppm in corrected distance, and it is believed that even better results can be obtained. The system is described in detail, including modifications that would significantly increase its accuracy and range.
Author: K. B. Earnshaw
Publisher:
ISBN:
Category : Distances
Languages : en
Pages : 132
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Book Description
Author: K. B. Earnshaw
Publisher:
ISBN:
Category : Distances
Languages : en
Pages : 120
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 88
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Book Description
The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.
Author: Wolfgang Torge
Publisher: Walter de Gruyter
ISBN: 3110250004
Category : Technology & Engineering
Languages : en
Pages : 444
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Book Description
The fourth edition of this textbook has been thoroughly revised in order to reflect the central role which geodesy has achieved in the past ten years. The Global Geodetic Observing System established by the IAG utilizes a variety of techniques to determine the geometric shape of the earth and its kinematics, the variations of earth rotation, and the earth’s gravity field. Space techniques play a fundamental role, with recent space missions also including gravity field recovery. Terrestrial techniques are important for regional and local applications, and for validating the results of the space missions. Global and regional reference systems are now well established and widely used. They also serve as a basis for geo-information systems. The analysis of the time variation of the geodetic products provides the link to other geosciences and contributes to proper modelling of geodynamic processes. The book follows the principal directions of geodesy, providing the theoretical background as well as the principles of measurement and evaluation methods. Selected examples of instruments illustrate the geodetic work. An extensive reference list supports further studies. The book is intended to serve as an introductory textbook for graduate students as well as a reference for scientists and engineers in the fields of geodesy, geophysics, surveying engineering and geomatics.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1038
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Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Author:
Publisher:
ISBN:
Category : Electric industries
Languages : en
Pages : 1248
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Book Description
Author: Jean M. Rüeger
Publisher: Springer Science & Business Media
ISBN: 3642971962
Category : Science
Languages : en
Pages : 304
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Book Description
The book has evolved from the author's continuing teaching of the subject and from two editions of a text of the same title. The first edition was published in 1978 by the School of Surveying, Universi ty of New South Wales, Sydney, Australia. Like its predecessors, this totally revised third edition is designed to make the subject matter more readily available to students proceeding to degrees in Survey ing and related fields. At the same time, it is a comprehensive refer ence book for all surveyors as well as for other professionals and scientists who use electronic distance measurement as a measuring tool. Great emphasis is placed on the understanding of measure ment principles and on proper reduction and calibration pro cedures. It comprises an extensive collection of essential formulae, useful tables and numerous literature references. After a review of the history of EDM instruments in Chapter 1, some fundamental laws of physics and units relevant to EDM are revised in Chapter 2. Chapter 3 discusses the principles and applica tions of the pulse method, the phase difference method, the Doppler technique and includes an expanded section on interferometers. The basic working principles of electro-optical and microwave distance meters are presented in Chapter 4, with special emphasis on modu lation/demodulation techniques and phase measurement systems. Important properties of infrared emitting and lasing diodes are discussed.
Author: V. J. Urick
Publisher: John Wiley & Sons
ISBN: 1119029805
Category : Technology & Engineering
Languages : en
Pages : 496
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Book Description
A comprehensive resource to designing and constructing analog photonic links capable of high RF performance Fundamentals of Microwave Photonics provides a comprehensive description of analog optical links from basic principles to applications. The book is organized into four parts. The first begins with a historical perspective of microwave photonics, listing the advantages of fiber optic links and delineating analog vs. digital links. The second section covers basic principles associated with microwave photonics in both the RF and optical domains. The third focuses on analog modulation formats—starting with a concept, deriving the RF performance metrics from basic physical models, and then analyzing issues specific to each format. The final part examines applications of microwave photonics, including analog receive-mode systems, high-power photodiodes applications, radio astronomy, and arbitrary waveform generation. Covers fundamental concepts including basic treatments of noise, sources of distortion and propagation effects Provides design equations in easy-to-use forms as quick reference Examines analog photonic link architectures along with their application to RF systems A thorough treatment of microwave photonics, Fundamentals of Microwave Photonics will be an essential resource in the laboratory, field, or during design meetings. The authors have more than 55 years of combined professional experience in microwave photonics and have published more than 250 associated works.
Author: Aeronautical Chart and Information Center (U.S.)
Publisher:
ISBN:
Category : Geodesy
Languages : en
Pages : 86
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Book Description
