Rubidium Atomic Clock: The Workhorse Of Satellite Navigation


Book Description

The Rubidium atomic clock (Rb) is the workhorse of the satellite navigation systems of which GPS is now a household name. With just the tap of a few keys, drivers and navigators all over the world are able to reach their destination effortlessly with high precision. People are now curious to know what makes this possible. Hence, the need to explain in simplistic terms the Rb atomic clocks that are onboard these satellite navigation systems because no good satellite navigation system is possible without such clocks.But why only Rb atomic clocks when far better and exotic atomic clocks are available? The reasons are as simple as that they are slim, low in weight, easy to build inexpensively. They are also used in numerous military applications such as secure communications, electronic warfare, command and control, telemetry and navigation. Besides, they are used in the measurements of the variation in fine-structure constant, test of relativity, precise spectroscopy and scientific research.This book details the history of time keeping and the chronological development of the Rb atomic clocks, with special focus on the physics Package that accounts for the actual performance of the clock. Researchers and industrialists will find that producing such clocks is relatively simple and inexpensive.




Rubidium Atomic Clock


Book Description




An Assessment of Precision Time and Time Interval Science and Technology


Book Description

Knowledge of time is essential to precise knowledge of location, and for this reason the Navy, with its need to navigate on the high seas, has historically played an important role in the development and application of advanced time realization and dissemination technologies. Discoveries coming from basic research funded by the Office of Naval Research (ONR) lie at the heart of today's highest performance atomic clocks, Naval Research Laboratory (NRL) expertise played a role in developing the space-qualified atomic clocks that enable the Global Positioning System (GPS), and the U.S. Naval Observatory (USNO) maintains and disseminates the standard of time for all of the Department of Defense (DOD). The Navy has made major investments in most aspects of precision time and time interval (PTTI) science and technology, although specific PTTI-related research has also been funded by the Defense Advanced Research Projects Agency (DARPA) and non-DOD agencies such as the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the Department of Commerce. Navy funding, largely through ONR, has a history of being an early enabler of key new developments. Judicious funding decisions by the Navy-particularly by ONR program officers-have underpinned most of the major advances in PTTI science and technology (S&T) in the last 50 years. PTTI is important to modern naval needs, and indeed to all the armed Services, for use in both navigation and communications. Precise time synchronization is needed to efficiently determine the start of a code sequence in secure communications, to perform navigation, and to locate the position of signal emitters. Precise frequency control is required in communications for spectrum utilization and frequency-hopped spread-spectrum techniques. There are many examples of essential military operations that depend on PTTI and could benefit from improvements in PTTI technology. These include: -GPS clocks and autonomous operations, -Weapon system four-dimensional coordination, -GPS antijamming, -Network-centric warfare, and -Secure military communications. This report summarizes that reductions in the size, weight, and power requirements and increases in the ruggedness of PTTI devices without sacrificing performance would put more accurate and precise timekeeping in the hands of the warrior, improving capabilities in all of the above operations.




Global Navigation Satellite Systems


Book Description

Global Navigation Satellite Systems (GNSS) and their associated technologies have advanced by leaps and bounds in the nine years since the first edition of this book was published. The concept of survey has changed, especially in the disciplines of geomatics and geoinformatics. This revised and updated second edition provides a thorough understanding of the basic principles and techniques of GNSS, analyzes all four active systems, and explains clearly how each of these systems works. Because of its straightforward treatment of the subject, readers will gain an insight into the techniques, trends, and applications of GNSS and develop knowledge on selecting an appropriate GNSS instrument. Written for students and practitioners in geoinformatics, geomatics engineering, surveying, and remote sensing and GIS, this introductory and practical book includes questions and exercises in each chapter. Key Features: • Furnishes detailed information on GPS, GLONASS, Galileo, BeiDou, and other regional and augmented systems • Provides practical guidance for surveying, mapping, and navigation with GNSS • Sheds light on the latest developments and modern trends of GNSS • Includes a detailed glossary of related terms • Contains many illustrations that complement the text • Exercises for each chapter • MCQ, solution manual for mathematical problems, and PPT as online resources




Introduction to GPS


Book Description

If you're looking for an up-to-date, easy-to-understand treatment of the GPS (Global Positioning System), this one-of-a-kind resource offers you the knowledge you need for your work, without bogging you down with advanced mathematics. It addresses all aspects of the GPS, emphasizes GPS applications, examines the GPS signal structure, and covers the key types of measurement being utilized in the field today.




Physics in a New Era


Book Description

Physics at the beginning of the twenty-first century has reached new levels of accomplishment and impact in a society and nation that are changing rapidly. Accomplishments have led us into the information age and fueled broad technological and economic development. The pace of discovery is quickening and stronger links with other fields such as the biological sciences are being developed. The intellectual reach has never been greater, and the questions being asked are more ambitious than ever before. Physics in a New Era is the final report of the NRC's six-volume decadal physics survey. The book reviews the frontiers of physics research, examines the role of physics in our society, and makes recommendations designed to strengthen physics and its ability to serve important needs such as national security, the economy, information technology, and education.




Apollo's Warriors


Book Description

Presenting a fascinating insider's view of U.S.A.F. special operations, this volume brings to life the critical contributions these forces have made to the exercise of air & space power. Focusing in particular on the period between the Korean War & the Indochina wars of 1950-1979, the accounts of numerous missions are profusely illustrated with photos & maps. Includes a discussion of AF operations in Europe during WWII, as well as profiles of Air Commandos who performed above & beyond the call of duty. Reflects on the need for financial & political support for restoration of the forces. Bibliography. Extensive photos & maps. Charts & tables.




Yearbook on Space Policy 2007/2008


Book Description

At the time of ?nalising this second volume of the ?Yearbook on Space Policy? which covers the period mid-2007 to mid-2008, Europe is as visible and strong in the area of space activities as never before. Its space probes are present on the Moon, around Mars, and on Saturn?s Moon Titan, and are chasing asteroids and comets; Ariane V is the most successful commercial launch vehicle; and more and more European space applications satellites are in operation. Finally, with the successful launch of the Columbus Orbital Facility (COF) – the most prominent highlight of this period which is also depicted on the cover of this Yearbook – and the ?rst Automated Transfer Vehicle (ATV), Europe has become a decisive player in human space?ight. This is accompanied by new policy initiatives on the ministerial level which have been bringing the European Space Agency and the European Union steadily closer. Europe?s outstanding development and positioning in the space ?eld is based not only on Europe?s successful engineering and scienti?c capabilities and capacities, but also on the forceful political determination of all European actors to maintain and even further their engagement in the use of outer space. And it is this political determination which provides the focus for this ?Yearbook on Space Policy?. The Yearbook describes and analyses the contexts and contents of space policy. Its primary ?eld of investigation is Europe, but it also covers the whole range of global space activities and their in?uence on European endeavours.




Beyond Horizons


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Global Geodetic Observing System


Book Description

The Global Geodetic Observing System (GGOS) has been established by the Int- national Association of Geodesy (IAG) in order to integrate the three fundamental areas of geodesy, so as to monitor geodetic parameters and their temporal varia- ?9 tions, in a global reference frame with a target relative accuracy of 10 or b- ter. These areas, often called ‘pillars’, deal with the determination and evolution of (a) the Earth’s geometry (topography, bathymetry, ice surface, sea level), (b) the Earth’s rotation and orientation (polar motion, rotation rate, nutation, etc. ), and (c) the Earth’s gravity eld (gravity, geoid). Therefore, Earth Observation on a global scale is at the heart of GGOS’s activities, which contributes to Global Change - search through the monitoring, as well as the modeling, of dynamic Earth processes such as, for example, mass and angular momentum exchanges, mass transport and ocean circulation, and changes in sea, land and ice surfaces. To achieve such an - bitious goal, GGOS relies on an integrated network of current and future terrestrial, airborne and satellite systems and technologies. These include: various positioning, navigation, remote sensing and dedicated gravity and altimetry satellite missions; global ground networks of VLBI, SLR, DORIS, GNSS and absolute and relative gravity stations; and airborne gravity, mapping and remote sensing systems.