Assessment of EGM2008 over Britain using vertical deflections, and the problems with historical data

Vertical deflections synthesised from the Earth Gravitational Model 2008 (EGM2008) agree with astrogeodetic vertical deflections observed over mainland Britain to within ~1.2" RMS (north-south) and ~1.4" RMS (east-west), which is commensurate with values reported for North America, Austral...

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Main Authors: Featherstone, Will, Olliver, J
Format: Journal Article
Published: Maney Publishing 2013
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/46481
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author Featherstone, Will
Olliver, J
author_facet Featherstone, Will
Olliver, J
author_sort Featherstone, Will
building Curtin Institutional Repository
collection Online Access
description Vertical deflections synthesised from the Earth Gravitational Model 2008 (EGM2008) agree with astrogeodetic vertical deflections observed over mainland Britain to within ~1.2" RMS (north-south) and ~1.4" RMS (east-west), which is commensurate with values reported for North America, Australia and parts of continental Europe. For this assessment in Britain, there has been the additional need to transform the observed relative vertical deflections to absolute ones. Not applying horizontal datum transformations led to spurious results, so absolute vertical deflections must always be used to assess EGMs. Three datum transformations were trialled (three-parameter, seven-parameter and OSTN02), which show similar results when considering the estimated ~0.3" precision of these historical (1950 to 1976) astrogeodetic observations. Several other problems were encountered because of the historical nature of the data, comprising destruction of survey pillars, ambiguous station names, and a mixture of horizontal geodetic datums available in Britain.
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spelling curtin-20.500.11937-464812017-09-13T13:39:37Z Assessment of EGM2008 over Britain using vertical deflections, and the problems with historical data Featherstone, Will Olliver, J vertical deflections EGM2008 British geodetic datums Vertical deflections synthesised from the Earth Gravitational Model 2008 (EGM2008) agree with astrogeodetic vertical deflections observed over mainland Britain to within ~1.2" RMS (north-south) and ~1.4" RMS (east-west), which is commensurate with values reported for North America, Australia and parts of continental Europe. For this assessment in Britain, there has been the additional need to transform the observed relative vertical deflections to absolute ones. Not applying horizontal datum transformations led to spurious results, so absolute vertical deflections must always be used to assess EGMs. Three datum transformations were trialled (three-parameter, seven-parameter and OSTN02), which show similar results when considering the estimated ~0.3" precision of these historical (1950 to 1976) astrogeodetic observations. Several other problems were encountered because of the historical nature of the data, comprising destruction of survey pillars, ambiguous station names, and a mixture of horizontal geodetic datums available in Britain. 2013 Journal Article http://hdl.handle.net/20.500.11937/46481 10.1179/1752270613Y.0000000048 Maney Publishing fulltext
spellingShingle vertical deflections
EGM2008
British geodetic datums
Featherstone, Will
Olliver, J
Assessment of EGM2008 over Britain using vertical deflections, and the problems with historical data
title Assessment of EGM2008 over Britain using vertical deflections, and the problems with historical data
title_full Assessment of EGM2008 over Britain using vertical deflections, and the problems with historical data
title_fullStr Assessment of EGM2008 over Britain using vertical deflections, and the problems with historical data
title_full_unstemmed Assessment of EGM2008 over Britain using vertical deflections, and the problems with historical data
title_short Assessment of EGM2008 over Britain using vertical deflections, and the problems with historical data
title_sort assessment of egm2008 over britain using vertical deflections, and the problems with historical data
topic vertical deflections
EGM2008
British geodetic datums
url http://hdl.handle.net/20.500.11937/46481