Highly Accurate Real-Time GPS Carrier Phase-Disciplined Oscillator
Resource
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, VOL. 54, NO. 2, APRIL 2005
Journal
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
Journal Volume
VOL. 54
Journal Issue
NO. 2
Pages
-
Date Issued
2005-04
Date
2005-04
Author(s)
Cheng, Chia-Lung
Chang, Fan-Ren
Tu, Kun-Yuan
DOI
246246/200611150121247
Abstract
A low-cost highly accurate real-time GPS carrier
phase disciplined oscillator system based on a single-frequency
receiver is presented. In order to estimate the average frequency
offsets of an oven-controlled crystal oscillator (OCXO) with
respect to the GPS, the OCXO was connected to a modified GPS
receiver to replace its original oscillator. Hence, the behavior of the
OCXO was determined from the GPS carrier phase observations.
The average frequency offsets of the OCXO with respect to the
GPS could be estimated by performing difference operations
on carrier phase observations of all satellites in view between
two measurement epochs. To overcome the interference coming
from the atmospheric delay, a real-time dynamic neural-wavelet
forecasting filter was proposed. The parameters of the filter were
obtained according to the results of a three-day experiment,
in which the GPS carrier phase observations of a stand-alone
configuration and a common-view configuration were compared.
The compressed average frequency offsets were then used by
the neural model predictive controller (MPC) for steering the
OCXO via D/A converters. From our experiments, the normalized
frequency offset of the disciplined OCXO could be improved
from about two parts in 109 to about three parts in 1014, and the
frequency stability (MDEV) could be improved from about eight
parts in 1010 to about four parts in 1014 over 24 h.
Subjects
Atmospheric delay
disciplined oscillator
neuralwavelet
Publisher
Taipei:National Taiwan University Dept Comp Sci Informat Engn
Type
journal article
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