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Atmospheric Effects and Spurious Signals in GPS Analysis
Citation
Tregoning, P and Watson, CS, Atmospheric Effects and Spurious Signals in GPS Analysis, Journal of Geophysical Research, 114, (B09403) pp. 1-15. ISSN 0148-0227 (2009) [Refereed Article]
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Copyright Statement
Copyright 2009 by the American Geophysical Union
Official URL: http://www.agu.org/journals/jgr/
Abstract
Improvements in the analyses of Global Positioning System (GPS) obser-
vations yield resolvable mm to sub-mm dierences in coordinate estimates, thus provid-
ing sucient resolution to distinguish subtle dierences in analysis methodologies. Here
we investigate the eects on site coordinates of using dierent approaches to modelling
atmospheric loading deformation (ATML) and handling of tropospheric delays. The rig-
orous approach of using the time-varying VMF1 mapping function yields solutions with
lower noise at a range of frequencies compared with solutions generated using empiri-
cal mapping functions. This is particularly evident when ATML is accounted for. Some
improvement also arises from using improved a priori zenith hydrostatic delays (ZHD),
with the combined eect being site specic. Importantly, inadequacies in both mapping
functions and a priori ZHDs not only introduce time correlated noise but signicant pe-
riodic terms at solar annual and semi-annual periods. We nd no signicant dierence
between solutions where non-tidal ATML is applied at the observation level rather than
as a daily-averaged value but failing to model diurnal and semi-diurnal tidal ATML at
the observation level can introduce anomalous propagated signals with periods that closely
match the GPS draconitic annual (351.4 d) and semi-annual period (175.7 d). Ex-
acerbated by not xing ambiguities, these signals are evident in both stacked and sin-
gle site power spectra, with each tide contributing roughly equally to the dominant semi-
annual peak. The amplitude of the propagated signal reaches a maximum of 0.8 mm with
a clear latitudinal dependence that is not correlated directly with locations of maximum
tidal amplitude.
This is the first evidence of aliased signals being produced from tidal ATML deformations.
Item Details
Item Type: | Refereed Article |
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Keywords: | Global Positioning System (GPS); Atmospheric effects; Atmospheric loading deformation |
Research Division: | Earth Sciences |
Research Group: | Geophysics |
Research Field: | Geodesy |
Objective Division: | Expanding Knowledge |
Objective Group: | Expanding knowledge |
Objective Field: | Expanding knowledge in the earth sciences |
UTAS Author: | Watson, CS (Dr Christopher Watson) |
ID Code: | 57192 |
Year Published: | 2009 |
Web of Science® Times Cited: | 132 |
Deposited By: | Geography and Environmental Studies |
Deposited On: | 2009-06-24 |
Last Modified: | 2022-07-06 |
Downloads: | 12 View Download Statistics |
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