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An Assessment of Precision Time and Time Interval Science and Technology (2002) / Chapter Skim
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1. The Navy and PTTI
Pages 7-11

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From page 7...
... Atomic Clocks The advances that had been made in high-frequency electronics during World War II radar research set the stage for the development of atomic clocks.2 In 1942 the Joint Chiefs of Staff established a iThe story of the search for a practical method of determining longitude at sea is told by Dava Sobel in Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time, Walker and Co., New York, N.Y., October 1995. 2For a more complete discussion of the history of atomic clocks, see Norman F
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From page 8...
... Forty years later, this clock technology still produces the best short- to medium-term clock stability commercially available. These three clock types the cesium atomic beam, the rubidium gas cell, and the hydrogen maser make up the totality of our commercially available atomic clock technology.
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From page 9...
... NRL became a key participant in the development of advanced atomic clocks for flight in GPS satellites. This NRL program nurtured industrial development of space-qualified atomic clocks, developed alternative sources for clocks, supported advanced clock development, provided testing services for the space qualification of clocks, and, ultimately, provided an in-house expertise base from which all DOD space clock programs can draw.
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From page 10...
... Conversely, FDOA can be based on frequency differences observed over time by a moving receiver locating a fixed source, as might be used in electronic intelligence activities. Finally, radars require precise frequency for moving target indication.
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From page 11...
... It further states that the Chief of Naval Operations shall program funds necessary to maintain the DOD reference standard and the means for dissemination to the accuracies required by the components and user agencies. In addition to maintaining the DOD Master Clock for the DOD, USNO has an active research effort in clock development, time-scale algorithms, and time transfer through both GPS carrier phase and TWSTT.
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Key Terms

  • precise time
  • clock technology
  • time interval
  • global positioning
  • cesium atomic

  • time difference
  • time transfer
  • atomic beam
  • space clock
  • frequency differences

  • precise frequency
  • gps carrier
  • atomic clock
  • separated sites
  • track satellites

  • naval operations
  • clock development
  • radio propagation
  • carrier phase
  • cavity design

  • nobel prize
  • propagation laboratory
  • time synchronization
  • time signals
  • concept led

  • frequency standards
  • tactical applications
  • widely separated
  • moderate performance
  • quickly abandoned


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