Download or read book Rubidium Atomic Clock The Workhorse Of Satellite Navigation written by G M Saxena and published by World Scientific. This book was released on 2020-03-05 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Rubidium Atomic Clock written by BIKASH. SAXENA GHOSAL (G M.) and published by . This book was released on 2019 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rubidium Atomic Clock for Galileo written by and published by . This book was released on 1999 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall performance of navigation payloads is dependent on the performance of the on-board clocks. Better stability leads directly to improved space segment autonomy and simplified ground segment operation. The European Space Agency supports the development of advanced atomic clocks in the frame of its Technology Demonstration Program and more recently under the GNSS-2 program. Two major activities are currently running with the aim fully space-qualifying a Rubidium Atomic Frequency Standard (RAFS) and a Space Hydrogen Maser (SHM). The development activity for the Rubidium clocks is driven by the following major design goals: * Mass
Download or read book GPS Block IIR Rubidium Atomic Frequency Standard Life Test written by and published by . This book was released on 1998 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rubidium clocks in the GPS Block IIR spacecraft have no previous flight experience, and will be the only atomic clocks used on the Block IIR satellites. The U.S. Naval Research Laboratory (NRL),) in cooperation with the Global Positioning System Joint Program Office (GPS-JPO), the GPS control Segment, Lockheed Martin, ITT, and EC & G, is conducting a three year life-test of two flight qualfied EG & G Rubidium Atomic Frequency Standards (RAFS) selected from the operational spacecraft inventory. The two RAFS, serial numbers 28 and 30, were selected as representative of the flight configuration build for Block IIR by ITT and provided by the JPO to NRL for this test. The test is intended to build confidence in these units as operational spacecraft clocks and establish a database of fundamental performance characteristics. The two units are being operated in independent thermal vacuum chambers with high resolution monitoring of the clock's frequency compared to the NRL hydrogen maser references. The units' internal monitors that would normally be sent as telemehy and environmental test conditions are monitored and recorded with high resolution. Output from one of the two units has been used as input to the NRL Time Keeping System Simulator (TKSS). The TKSS was originally built to evaluate the implementation and algorithms used in the Block IIR on-board Time Keeping System (TKS), which determines the satellite's clock signal to the transmitter. Data from the TKSS have been used to evaluate TKS on-orbit performance and serve as an analysis reference. RAFS data from the beginning of the test on 31 March 1997 to August 1998 and representative TKSS data will be presented. Frequency stability results of the RAFS have routinely shown Allan deviation performance in parts in 10( -14) at one day, much better than initially expected.
Download or read book A Rubidium Clock for GPS written by and published by . This book was released on 1981 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work at EG&G, Inc. on a second-source rubidium frequency standard for use in the GPS navigation satellites has now reached the prototype stage. This paper describes (1) the design objectives and approach, (2) the more important design features, (3) the signal parameters and error budget, and (4) the early results of this program up to the present.
Download or read book Rubidium Atomic Frequency Standards for GPS Block IIR written by and published by . This book was released on 1990 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: EG & G, Inc. has been selected to provide the Rubidium Atomic Frequency Standards (RAFS) for the GPS Block IIR NAVSTAR satellites. These satellites will replenish and upgrade the space segment of the Global Positioning System in the mid 1990s. The EG & G GPS RAFS Rb clocks are the latest generation of the high-performance rubidium frequency standards described at this conference in 1981, 1983, 1985, and 1987. They offer an aging rate in the low pp10(14)/day range and a drift-corrected 1-day stability in the low pp10(14) range. The Block IIR version of these devices will have improved performances, higher reliability, smaller size, and greater radiation hardness. The GPS Block IIR atomic clocks have a "natural frequency" configuration whereby they output a frequency of about 13.4 MHz that is a submultiple of the atomic resonance of Rb (or Cs). The RAFS operates at a low, fixed C-field for increased stability. The unit has been repackaged into a smaller 4.6" x 8.5" x 5.8" outline, but is somewhat heavier (12 lbs.) because of additional radiation shielding. Elimination of the ground tuning logic and the secondary loop synthesizer (with its ovenized crystal oscillator) has reduced the RAFS complexity and improved its reliability to 0.80 for the 7.5-year mission. The RAFS power consumption is only 13 W at +20 deg. C in vacuum. This paper describes the GPS Block IIR RAFS design, including the changes and improvements made, and the test results obtained, since the last report at this conference in 1987.
Download or read book Early In Orbit Performance of GPS Block IIR Rubidium Clocks written by and published by . This book was released on 1997 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first Block IIR GPS navigation satellite, placed in orbit on July 22, 1997, carried a new generation of rubidium clocks. Since then, two of these clocks have been activated, and both are performing well. This paper reports on those early results, and compares the in-orbit performance with ground acceptance test data. EG & G has delivered about two-thirds of the 66 Rubidium Atomic Frequency Standards (RAFS) needed for the Block IIR GPS program Composite frequency and time stability plots are presented for all delivered units, and more detailed acceptance test stability data shown for the two RAFS that are operating on-board SVN43. In addition, similar life test data shown for the two units that are undergoing life testing at NRL. In-orbit stability and drift data are presented for RAFS S/N 005 and 006 using all available 15-minute precise ephemeris/clock data from the National Imagery and Mapping Agency (NIMA). RAFS S/N 006 was turned on 8/13/97 and was used as the active clock until 9/26/97. RAFS S/N 005 was turned on 8/22/97 and became the active clock on 9/26/97 at the beginning of a 2-month extended navigation test. Both are showing excellent stability and early drift stabilization.
Download or read book An Assessment of Precision Time and Time Interval Science and Technology written by National Research Council and published by National Academies Press. This book was released on 2002-12-04 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Global Navigation Satellite Systems written by Basudeb Bhatta and published by CRC Press. This book was released on 2021-05-09 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book The Rubidium Atomic Clock and Basic Research written by and published by . This book was released on 2007 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The vapor-cell atomic clock finds application today in the global positioning system and telecommunications. To improve and miniaturize the humble device for future applications will require a deeper understanding of atomic and chemical physics.
Download or read book Test Results for Prototype GPS Global Positioning System Rubidium Clocks written by and published by . This book was released on 1984 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the results of a series of stability and qualification-level environmental and performance tests on two prototype rubidium frequency standards for the GPS navigation satellite program.
Download or read book Further Test Results for Prototype GPS Rubidium Clocks written by and published by . This book was released on 1985 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the results of further stability and qualification-level environmental tests on two prototype rubidium frequency standards for the GPS navigation satellite program. One unit was subjected to a 140-day thermovac stability retest that confirmed the efficacy of two improvements that reduce frequency drift and frequency and light intensity fluctuations. The observed drift was -1.4 x 10( -14)/day and the stability was 6 x 10( -14) at 10(5) seconds. This was accomplished by using an absorption cell made from glass having low helium permeability and a lamp having a lower (normal) rubidium fill. The other unit was successfully subjected to qualification levels of thermal, mechanical and EMI retesting. Several electrical, high temperature, and mechanical problems associated with the ovenized crystal oscillator were corrected. Improved design and filtering of the control/monitor cable and power supply satisfactorily resolved several EMI problems.
Download or read book Long Term Ground Test Results for Two GPS Block IIR Rubidium Clocks written by Ronald L. Beard and published by . This book was released on 2000 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rubidium clock used in the GPS Block IIR space vehicles is a design that had not flown previously in space.
Download or read book GPS IIR Rubidium Clocks In Orbit Performance Aspects written by and published by . This book was released on 2004 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The GPS Block IIR rubidium clocks have proved to be the best performers in the current GPS constellation, starting with the first IIR operational clock (launched on July 23, 1997). This discussion covers a number of topics, including the frequency accuracy, the frequency variation, and the projected lifetimes of these clocks. The performance of these clocks in orbit and their life expectancy are compared with that experienced with previous GPS clocks. The superior performance and lifetimes of the GPS IIR Rb clocks are highlighted. Because these clocks are so well behaved, it has been possible to detect various features and phenomena that were not previously detectable. The full drift of the IIR clocks is not observed by the user because of onboard cancellation by the Time Keeping System. The diagnostic and reprogrammability capability of the GPS IIR Satellites allows these discrepancies to be addressed. The long-lived features of the clocks indicate that they will outlive the GPS satellite mission duration.
Download or read book Atomic Clocks of the National Bureau of Standards written by and published by . This book was released on 1978 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atomic and Quartz Clock Hardware for Communication and Navigation Satellites written by and published by . This book was released on 2007 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate and stable frequency reference sources are critical for commercial, navigation, military, and scientific space applications. Each piece of flight hardware has requirement-types that are generic such as size, weight, power, and reliability, and requirement-types that are specific to the hardware function. The key requirement-types for frequency reference sources are phase noise and stability. Both are important for satellites, but stability is especially important for navigation satellites. Several levels of frequency references are suitable for space applications. This paper discusses similarities and differences among single distributed oscillators for communications satellites, master oscillator groups for communications systems, and atomic clocks for military and navigation systems.
Download or read book The Measurement of Time written by Claude Audoin and published by Cambridge University Press. This book was released on 2001-09-06 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: A unique insight into the measurement of time and its applications, at an introductory level.
