GPS Time Steering

Abstract

The importance of the Global Positioning System (GPS) for global time transfer makes it desirable to steer GPS time as closely as possible to the UTC rate. Currently, GPS time is maintained to satisfy two system requirements. First, GPS time is steered to within one microsecond of UTC(USNO) when the leap seconds imposed on UTC since 1980 have been removed. Second, the GPS Navigation Message gives the offset UTC(USNO) - GPS time to users with an error not to exceed 100 nanoseconds. User performance would be improved, however, if changes in the GPS time rate were smaller and more gradually imposed than at present. Three current developments are expected to improve GPS time steering performance: the installation of a stable clock ensemble at the GPS Master Control Station: improvement of supporting hardware; and application of control theory to steering procedures.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1986
Accession Number
ADA492104

Entities

People

  • D. W. Allan
  • H. F. Fliegel
  • W. J. Klepczynski

Organizations

  • United States Naval Observatory

Tags

Communities of Interest

  • Space

DTIC Thesaurus Topics

  • Abstracts
  • Accuracy
  • Artificial Satellites
  • Atomic Beam Masers
  • Clocks
  • Control Theory
  • Errors
  • Frequency
  • Frequency Standards
  • Global Positioning Systems
  • Loran
  • Microsecond Time
  • Nanosecond Time
  • Navigation
  • Observatories
  • Standards
  • Time Intervals

Fields of Study

  • Computer science

Readers

  • Atmospheric Science/Meteorology
  • Inertial Navigation Systems.
  • Robotics and Automation.

Technology Areas

  • Space
  • Space - Spacecraft Maneuvers