A Total Estimator of the Hadamard Function Used for GPS Operations

Abstract

We describe a method based on the Total deviation approach whereby we improve the confidence of the estimation of the Hadamard deviation that is used primarily in GPS operations. The Hadamard-total deviation described in this paper provides a significant improvement in confidence indicated by an increase of 1.3 to 3.4 times the one degree of freedom of the plain Uadamard deviation at the longest averaging time. The new Hadamard-total deviation is slightly negativdy biased with respect to the usual Uadamard deviation, and T values are restricted to less than or equal to T/3, to be consistent with the usual Uadamard's definition. We give a method of automatically removing bias by a power-law detection scheme. We review the relationship between Kalman fiber parameters and the Hadamard and Allan variances, illustrate the operational problems associated with estimating these parameters, and discuss how the Uadamard-total variance can improve management of present and future GPS satellite clocks.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 2001
Accession Number
ADA484835

Entities

People

  • Bill Riley
  • Chuck Greenhall
  • Dave Howe
  • Francois Vernotte
  • Ron Beard

Organizations

  • National Institute of Standards and Technology

Tags

Communities of Interest

  • Space

DTIC Thesaurus Topics

  • Algorithms
  • Ambiguity
  • Artificial Satellites
  • Boundaries
  • Clocks
  • Coefficients
  • Computations
  • Detection
  • Electronic Mail
  • Estimators
  • Jet Propulsion
  • Kalman Filters
  • Sampling
  • Standards
  • Statistical Algorithms
  • Statistical Estimation
  • Time Intervals

Readers

  • Approximation Theory.
  • Positioning, Navigation, and Timing (PNT) Technology.

Technology Areas

  • Space