Evaluation of GPS Block IIR Time Keeping System for Integrity Monitoring

Abstract

Onboard GPS clock monitoring will be required for GPS III satellites. This paper will discuss some of the key integrity monitoring parameters in the context of the GPS Block IIR TKS. The paper will also show that: (1) the phase meter output, comparing the phase difference of the Rb Atomic Frequency Standard (AFS) and the VCXO in a 1.5-second GPS epoch, behaves like a Gaussian distribution; (2) The TKS probability of false alarm is almost equal to zero due to its rather large detection threshold; (3) The TKS can detect and compensate for "large" VCXO frequency steps with no significant TKS output phase error; (4) The TKS cannot compensate "large" VCXO frequency drift steps and may require a MCS "Master Control Station" contingency upload to remove phase bias; (5) The TKS cannot detect "large" AFS frequency steps or frequency drift steps that cause the TKS output phase error to run away, but steps of that type have not be observed in IIR operation so far.

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Document Details

Document Type
Technical Report
Publication Date
Nov 01, 2007
Accession Number
ADA483442

Entities

People

  • Andy Wu

Organizations

  • The Aerospace Corporation

Tags

DTIC Thesaurus Topics

  • Artificial Satellites
  • Data Science
  • Detection
  • Distribution Functions
  • False Alarms
  • Gaussian Distributions
  • Monitoring
  • Normal Distribution
  • Phase Meters
  • Probability
  • Probability Density Functions
  • Probability Distribution Functions
  • Probability Distributions
  • Standards
  • Test And Evaluation
  • Time Intervals
  • Warning Systems

Fields of Study

  • Physics

Readers

  • Positioning, Navigation, and Timing (PNT) Technology.
  • Statistical inference.

Technology Areas

  • Space
  • Space - Space Objects