Gps Block Iir Rubidium Atomic Frequency Standard Life Test
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Gps Block Iir Rubidium Atomic Frequency Standard Life Test
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Author :
language : en
Publisher:
Release Date : 1998
Gps Block Iir Rubidium Atomic Frequency Standard Life Test written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with categories.
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.
Gps Block Iif Rubidium Frequency Standard Life Test
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Author :
language : en
Publisher:
Release Date : 2009
Gps Block Iif Rubidium Frequency Standard Life Test written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with categories.
Since August 2008, two production PerkinElmer Rubidium Frequency Standards (RFS) built for the GPS Block IIF satellites have been under test at the Naval Research Laboratory (NRL) Precision Clock Evaluation Facility (PCEF). NRL, in conjunction with the GPS Wing, GPS Block IIF prime contractor Boeing, and the RFS manufacturer PerkinElmer, is conducting a minimum 3-year life test on the GPS IIF RFS units, serial numbers 5 and 25. The primary objectives of the program will be the verification of the design's life and reliability. A secondary objective will be the long-term characterization and evaluation of the GPS IIF RFS performance parameters. 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 telemetry and environmental test conditions are monitored and recorded with high resolution. A status will be presented of the GPS IIF RFS units under test.
Rubidium Atomic Frequency Standards For Gps Block Iir
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Author :
language : en
Publisher:
Release Date : 1990
Rubidium Atomic Frequency Standards For Gps Block Iir written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1990 with categories.
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.
Early In Orbit Performance Of Gps Block Iir Rubidium Clocks
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Author :
language : en
Publisher:
Release Date : 1997
Early In Orbit Performance Of Gps Block Iir Rubidium Clocks written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997 with categories.
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.
Long Term Ground Test Results For Two Gps Block Iir Rubidium Clocks
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Author : Ronald L. Beard
language : en
Publisher:
Release Date : 2000
Long Term Ground Test Results For Two Gps Block Iir Rubidium Clocks written by Ronald L. Beard and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with Aids to navigation categories.
The rubidium clock used in the GPS Block IIR space vehicles is a design that had not flown previously in space.
The 22nd Annual Precise Time And Time Interval Ptti Applications And Planning Meeting
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Author :
language : en
Publisher:
Release Date : 1990
The 22nd Annual Precise Time And Time Interval Ptti Applications And Planning Meeting written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1990 with categories.
Annual Precise Time And Time Interval Ptti Applications And Planning Meeting
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Author :
language : en
Publisher:
Release Date : 1994
Annual Precise Time And Time Interval Ptti Applications And Planning Meeting written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1994 with Time categories.
China Satellite Navigation Conference Csnc 2020 Proceedings Volume Ii
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Author : Jiadong Sun
language : en
Publisher: Springer Nature
Release Date : 2020-06-06
China Satellite Navigation Conference Csnc 2020 Proceedings Volume Ii written by Jiadong Sun and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-06-06 with Technology & Engineering categories.
China Satellite Navigation Conference (CSNC 2020) Proceedings presents selected research papers from CSNC 2020 held during 22nd-25th November in Chengdu, China. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 13 topics to match the corresponding sessions in CSNC2020, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.
26th Annual Precise Time And Time Interval Ptti Applications And Planning Meeting
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Author :
language : en
Publisher:
Release Date : 1995
26th Annual Precise Time And Time Interval Ptti Applications And Planning Meeting written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1995 with Crystals categories.
Rubidium And Cesium Frequency Standards Status And Performance On The Gps Program
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Author :
language : en
Publisher:
Release Date : 1986
Rubidium And Cesium Frequency Standards Status And Performance On The Gps Program written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1986 with categories.
The evolution of the frequency standards on the GPS program started with the Block I concept validation program, beginning with a proposal program in 1973 and followed by the (GPS 1 through 8) prototype space vehicle contract in 1974. The full-scale developmental (GPS 9 through 11) models contracted In 1978 provided both navigation and nuclear detection capability. The production qual vehicle (GPS 12) was contracted in 1980, and the production vehicles (GPS 13 through 40) were contracted in 1982. During the proposal phase of this program, the on-board frequency Standards were considered the most critical item within the GPS navigational system for achieving user position accuracy. Therefore, a considerable amount of effort was devoted to the frequency standards. The initial GPS vehicles (GPS 1 through 3) incorporated three rubidium frequency standards, each with a backup mode, to minimize the risk to the GPS program on this critical item. This was achieved by operating a high performance VCXO without its rubidium reference. This design concept resulted in the redundancy potential of six frequency standards per vehicle. Later space vehicles, starting with GPS 4, included an additional cesium frequency standard, also with a backup VCXO mode. This extended redundancy was deemed necessary in lieu of the more conventional dual redundancy because if the rubidium loop failed, then the VCXO could be utilized as a backup device that would maintain frequency stability for a specific period of time, as required, to maintain navigational accuracy over the test area. The actual on-orbit GPS frequency standard operating history shown in Figure 1 illustrates the results of this hardware implementation.