Estimating UTC - UTC (APL) at the JHU Applied Physics Laboratory

Abstract

Our master clock accuracy goal at the Time and Frequency Laboratory of the Johns Hopkins University Applied Physics Laboratory (JHU/APL) is to maintain UTC (APL) within plus-or-minus 20 nanoseconds of UTC. This is a challenging goal, because it requires the estimation of the future character of UTC - UTC (APL) up to 6 weeks beyond the latest issue of Circular T from the BIPM. Furthermore, the accuracy of our timescale-based estimation is challenged by the environmental influence on our ensemble of six clocks and the statistical limits to the dynamic characterization of these sources. This paper will describe the estimation algorithm used to determine the steering of UTC (APL). We will describe how the residual drift within the JHU/APL timescale affects our ability to estimate UTC - UTC (APL) and how we have modified the algorithm to remove this drift from the timescale prior to computing the estimation.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Dec 01, 2008
Accession Number
ADA503339

Entities

People

  • Gregory L. Weaver
  • Matthew J. Reinhart
  • Mihran Miranian

Organizations

  • Johns Hopkins University

Tags

Communities of Interest

  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Abstracts
  • Accuracy
  • Algorithms
  • Atomic Beam Masers
  • Atomic Clocks
  • Clocks
  • Computations
  • Data Sets
  • Discriminators
  • Electronic Mail
  • Frequency
  • Intervals
  • Masers
  • Nanosecond Time
  • Physics
  • Physics Laboratories
  • Time Intervals

Readers

  • Adaptive Control and Estimation with Uncertainty in Dynamic Systems.
  • Positioning, Navigation, and Timing (PNT) Technology.
  • Research Science/Academic Research