A New GPS-based evaluation of distortions in the Australian Height Datum in Western Australia

Previous work on assessing the errors in the Australian Height Datum (AHD) across Western Australia used fewer and older global positioning system (GPS) data and a global quasigeoid model. A larger and improved State-wide set of 243 GPS-derived ellipsoidal heights and a regional gravimetric quasigeo...

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Main Authors: Featherstone, Will, Filmer, Michael
Format: Journal Article
Published: Royal Society of Western Australia 2008
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/33123
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author Featherstone, Will
Filmer, Michael
author_facet Featherstone, Will
Filmer, Michael
author_sort Featherstone, Will
building Curtin Institutional Repository
collection Online Access
description Previous work on assessing the errors in the Australian Height Datum (AHD) across Western Australia used fewer and older global positioning system (GPS) data and a global quasigeoid model. A larger and improved State-wide set of 243 GPS-derived ellipsoidal heights and a regional gravimetric quasigeoid model are now available. Therefore, it is possible to re-evaluate the north-south tilt in the AHD and look for regional systematic distortions with some more confidence in Western Australia. This new analysis shows an apparent north-south tilt of ~0.27 mm/km in the existing AHD over the whole of the State, but which increases to ~0.6 mm/km over smaller regions, showing regional systematic distortions. When mean sea-level constraints are removed from the AHD by a minimally constrained least-squares adjustment of the spirit-levelling observations that is less prone to the effect of sea-surface topography, the north-south tilt reduces to ~0.18 mm/km, but the regional distortions remain, showing that errors are present in the spirit-levelling observations.
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spelling curtin-20.500.11937-331232017-01-30T13:35:07Z A New GPS-based evaluation of distortions in the Australian Height Datum in Western Australia Featherstone, Will Filmer, Michael levelling AHD Heights quasigeoid sea surface topography GPS geodesy Previous work on assessing the errors in the Australian Height Datum (AHD) across Western Australia used fewer and older global positioning system (GPS) data and a global quasigeoid model. A larger and improved State-wide set of 243 GPS-derived ellipsoidal heights and a regional gravimetric quasigeoid model are now available. Therefore, it is possible to re-evaluate the north-south tilt in the AHD and look for regional systematic distortions with some more confidence in Western Australia. This new analysis shows an apparent north-south tilt of ~0.27 mm/km in the existing AHD over the whole of the State, but which increases to ~0.6 mm/km over smaller regions, showing regional systematic distortions. When mean sea-level constraints are removed from the AHD by a minimally constrained least-squares adjustment of the spirit-levelling observations that is less prone to the effect of sea-surface topography, the north-south tilt reduces to ~0.18 mm/km, but the regional distortions remain, showing that errors are present in the spirit-levelling observations. 2008 Journal Article http://hdl.handle.net/20.500.11937/33123 Royal Society of Western Australia fulltext
spellingShingle levelling
AHD
Heights
quasigeoid
sea surface topography
GPS
geodesy
Featherstone, Will
Filmer, Michael
A New GPS-based evaluation of distortions in the Australian Height Datum in Western Australia
title A New GPS-based evaluation of distortions in the Australian Height Datum in Western Australia
title_full A New GPS-based evaluation of distortions in the Australian Height Datum in Western Australia
title_fullStr A New GPS-based evaluation of distortions in the Australian Height Datum in Western Australia
title_full_unstemmed A New GPS-based evaluation of distortions in the Australian Height Datum in Western Australia
title_short A New GPS-based evaluation of distortions in the Australian Height Datum in Western Australia
title_sort new gps-based evaluation of distortions in the australian height datum in western australia
topic levelling
AHD
Heights
quasigeoid
sea surface topography
GPS
geodesy
url http://hdl.handle.net/20.500.11937/33123