Rubidium Atomic Clock The Workhorse Of Satellite Navigation

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.

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 (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

If you want to know where you are, you need a good clock. The surprising connection between time and place is explored in Time and Navigation: The Untold Story of Getting from Here to There, the companion book to the National Air and Space Museum exhibition of the same name. Today we use smartphones and GPS, but navigating has not always been so easy. The oldest "clock" is Earth itself, and the oldest means of keeping time came from observing changes in the sky. Early mariners like the Vikings accomplished amazing feats of navigation without using clocks at all. Pioneering seafarers in the Age of Exploration used dead reckoning and celestial navigation; later innovations such as sextants and marine chronometers honed these techniques by measuring latitude and longitude. When explorers turned their sights to the skies, they built on what had been learned at sea. For example, Charles Lindbergh used a bubble sextant on his record-breaking flights. World War II led to the development of new flight technologies, notably radio navigation, since celestial navigation was not suited for all-weather military operations. These forms of navigation were extended and enhanced when explorers began guiding spacecraft into space and across the solar system. Astronauts combined celestial navigation technology with radio transmissions. The development of the atomic clock revolutionized space flight because it could measure billionths of a second, thereby allowing mission teams to navigate more accurately. Scientists and engineers applied these technologies to navigation on earth to develop space-based time and navigation services such as GPS that is used every day by people from all walks of life. While the history of navigation is one of constant change and innovation, it is also one of remarkable continuity. Time and Navigation tells the story of navigation to help us understand where we have been and how we got there so that we can understand where we are going.