Two Way Time Transfer Results at NRL and USNO

Abstract

The Naval Research Laboratory (NRL) has developed a two way time transfer modem system for the United States Naval Observatory (USNO). Two modems in conjunction with a pair of Very Small Aperture Terminal (VSAT) and a communication satellite can achieve sub nanosecond time transfer. This performance is demonstrated by the results of testing at and between NRL and USNO. The modems use Code Division Multiple Access (CDMA) methods to separate their signals through a single path in the satellite. Each modem transmitted a different Pseudo Random Noise (PRN) code and received the others PRN code. High precision time transfer is possible with two way methods because of reciprocity of many of the terms of the path and hardware delay between the two modems. The hardware description was given in a previous paper.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1992
Accession Number
ADA494565

Entities

People

  • G. P. Landis
  • Ivan J. Galysh

Organizations

  • United States Naval Research Laboratory

Tags

DTIC Thesaurus Topics

  • Artificial Satellites
  • Atomic Clocks
  • Clocks
  • Code Division Multiple Access
  • Communication Satellites
  • Frequency Standards
  • Intervals
  • Measurement
  • Military Research
  • Multiple Access
  • Nanosecond Time
  • New Jersey
  • Picosecond Time
  • Standards
  • Time Interval Counters
  • Time Intervals
  • United States

Readers

  • Positioning, Navigation, and Timing (PNT) Technology.
  • Radio communications and signal processing.

Technology Areas

  • Space