Interferometry in Radioastronomy and Radar Techniques


Book Description

In recent years aperture synthesis and interferometry have become very powerful tools in radioastronomy. Investigation of distant galaxies, for example, have revealed structures with sizes of less than a kiloparsec. In general, the study of galaxies has benefited from the great power of these techniques. Radar applications have also dramatically increased their quality by using the interferometry principle. Tracking and airborne radar can now determine position and velocity of objects with a much higher accuracy. This book describes in the first six, short chapters the basics of interferometry and aperture synthesis. The following two, long chapters treat the aspects of radioastronomical interferometers and radar applications of interferometry in great detail. The text offers readers a very good opportunity to familiarize themselves with the mathematical background of these very complex techniques. For researchers and students in radioastronomy and electrical engineering.




Interferometry and Synthesis in Radio Astronomy


Book Description

A unified description of the theory and practice of radio interferometry and synthesis mapping techniques as they apply to astronomy and geology. Beginning with an historical review, it goes on to provide a detailed description of all aspects of radio inferometry, from basic principles through instrumental design to data reduction. Over 450 original papers and monographs are cited.




Interferometry and Synthesis in Radio Astronomy


Book Description

This book is open access under a CC BY-NC 4.0 license. The third edition of this indispensable book in radio interferometry provides extensive updates to the second edition, including results and technical advances from the past decade; discussion of arrays that now span the full range of the radio part of the electromagnetic spectrum observable from the ground, 10 MHz to 1 THz; an analysis of factors that affect array speed; and an expanded discussion of digital signal-processing techniques and of scintillation phenomena and the effects of atmospheric water vapor on image distortion, among many other topics. With its comprehensiveness and detailed exposition of all aspects of the theory and practice of radio interferometry and synthesis imaging, this book has established itself as a standard reference in the field. It begins with an overview of the basic principles of radio astronomy, a short history of the development of radio interferometry, and an elementary discussion of the operation of an interferometer. From this foundation, it delves into the underlying relationships of interferometry, sets forth the coordinate systems and parameters to describe synthesis imaging, and examines configurations of antennas for multielement synthesis arrays. Various aspects of the design and response of receiving systems are discussed, as well as the special requirements of very-long-baseline interferometry (VLBI), image reconstruction, and recent developments in image enhancement techniques and astrometric observations. Also discussed are propagation effects in the media between the source and the observer, and radio interference, factors that limit performance. Related techniques are introduced, including intensity interferometry, optical interferometry, lunar occultations, tracking of satellites in Earth orbit, interferometry for remote Earth sensing, and holographic measurements of antenna surfaces. This book will benefit anyone who is interested in radio interferometry techniques for astronomy, astrometry, geodesy, or electrical engineering.




Angle-of-Arrival Estimation Using Radar Interferometry


Book Description

Radar interferometers provide a cost-effective radar architecture to achieve enhanced angle accuracy for enhanced target tracking. The objective of this book is to quantify interferometer angle estimation accuracy by developing a general understanding of various radar interferometer architectures and presenting a comprehensive understanding of the effects of radar-based measurement errors on angle-of-arrival estimation. As such this book is primarily directed toward tracking radars but will also discuss imaging applications as well.




Interferometry and Synthesis in Radio Astronomy


Book Description

Comprehensive, authoritative coverage of interferometric techniques for radio astronomy In this Second Edition of Interferometry and Synthesis in Radio Astronomy, three leading figures in the development of large imaging arrays, including very-long-baseline interferometry (VLBI), describe and explain the technology that provides images of the universe with an angular resolution as fine as 1/20,000 of an arcsecond. This comprehensive volume begins with a historical review followed by detailed coverage of the theory of interferometry and synthesis imaging, analysis of interferometer response, geometrical relationships, polarimetry, antennas, and arrays. Discussion of the receiving system continues with analysis of the response to signals and noise, analog design requirements, and digital signal processing. The authors detail special requirements of VLBI including atomic frequency standards, broadband recording systems, and antennas in orbit. Further major topics include: * Calibration of data and synthesis of images * Image enhancement using nonlinear algorithms * Techniques for astrometry and geodesy * Propagation in the neutral atmosphere and ionized media * Radio interference * Related techniques: intensity interferometry, moon occultations, antenna holography, and optical interferometry Interferometry and Synthesis in Radio Astronomy, Second Edition is comprehensive in that it provides an excellent overview of most radio astronomical instrumentation and techniques.




Essential Radio Astronomy


Book Description

The ideal text for a one-semester course in radio astronomy Essential Radio Astronomy is the only textbook on the subject specifically designed for a one-semester introductory course for advanced undergraduates or graduate students in astronomy and astrophysics. It starts from first principles in order to fill gaps in students' backgrounds, make teaching easier for professors who are not expert radio astronomers, and provide a useful reference to the essential equations used by practitioners. This unique textbook reflects the fact that students of multiwavelength astronomy typically can afford to spend only one semester studying the observational techniques particular to each wavelength band. Essential Radio Astronomy presents only the most crucial concepts—succinctly and accessibly. It covers the general principles behind radio telescopes, receivers, and digital backends without getting bogged down in engineering details. Emphasizing the physical processes in radio sources, the book's approach is shaped by the view that radio astrophysics owes more to thermodynamics than electromagnetism. Proven in the classroom and generously illustrated throughout, Essential Radio Astronomy is an invaluable resource for students and researchers alike. The only textbook specifically designed for a one-semester course in radio astronomy Starts from first principles Makes teaching easier for astronomy professors who are not expert radio astronomers Emphasizes the physical processes in radio sources Covers the principles behind radio telescopes and receivers Provides the essential equations and fundamental constants used by practitioners Supplementary website includes lecture notes, problem sets, exams, and links to interactive demonstrations An online illustration package is available to professors




Working Papers


Book Description

This volume contains working papers on astronomy and astrophysics prepared by 15 non-National Research Council panels in areas ranging from radio astronomy to the status of the profession.




A Strategy for Active Remote Sensing Amid Increased Demand for Radio Spectrum


Book Description

Active remote sensing is the principal tool used to study and to predict short- and long-term changes in the environment of Earth - the atmosphere, the oceans and the land surfaces - as well as the near space environment of Earth. All of these measurements are essential to understanding terrestrial weather, climate change, space weather hazards, and threats from asteroids. Active remote sensing measurements are of inestimable benefit to society, as we pursue the development of a technological civilization that is economically viable, and seek to maintain the quality of our life. A Strategy for Active Remote Sensing Amid Increased Demand for Spectrum describes the threats, both current and future, to the effective use of the electromagnetic spectrum required for active remote sensing. This report offers specific recommendations for protecting and making effective use of the spectrum required for active remote sensing.




Handbook of Frequency Allocations and Spectrum Protection for Scientific Uses


Book Description

The electromagnetic spectrum is a vital part of our environment. Measures of radio frequency emissions from natural phenomena enable both practical applications, such as weather predictions and studies of the changing of Earth's climate here at home, and reveal the physical properties of cosmic sources. The spectrum is therefore a resource to be used wisely now and to be protected for future generations. Handbook of Frequency Allocations and Spectrum Protection for Scientific Uses: Second Edition sets forth the principles for the allocation and protection of spectral bands for services using the radio spectrum for scientific research. This report describes the radio frequency bands used by scientific services and includes relevant regulatory information and discussion of scientific use of frequency bands. This reference will guide spectrum managers and spectrum regulatory bodies on science issues and serve as a resource to scientists and other spectrum users.




Open Skies


Book Description

This open access book on the history of the National Radio Astronomy Observatory covers the scientific discoveries and technical innovations of late 20th century radio astronomy with particular attention to the people and institutions involved. The authors have made extensive use of the NRAO Archives, which contain an unparalleled collection of documents pertaining to the history of radio astronomy, including the institutional records of NRAO as well as the personal papers of many of the pioneers of U.S. radio astronomy. Technical details and extensive citations to original sources are given in notes for the more technical readers, but are not required for an understanding of the body of the book. This book is intended for an audience ranging from interested lay readers to professional researchers studying the scientific, technical, political, and cultural development of a new science, and how it changed the course of 20th century astronomy.