Authors / CoAuthors
Brown, N.J. | Hu, G. | Featherstone, W.
Abstract
AUSGeoid09 is an order of magnitude more accurate than AUSGeoid98 at converting ellipsoidal heights to Australian Height Datum (AHD) heights and vice versa. Results of this study show AUSGeoid09 can be used to compute AHD values from Global Navigation Satellite System (GNSS) ellipsoidal heights with an uncertainty of less than 0.03 m (1 sigma). The improvement is largely due to the inclusion of a geometric component in AUSGeoid09 that accounts for the spatially varying offset between a gravimetric quasigeoid model and the AHD. This geometric component was calculated using least squares collocation in cross validation mode and then 'draped' over the gravimetric quasigeoid. Although previous AUSGeoid models were used to convert GNSS ellipsoidal heights to the AHD and vice versa, none until now have accounted for the gravimetric quasigeoid to AHD offsets. This is a consequence of how the AHD was realised and has commonly resulted in misfits of ~0.5 m or more. When used with GNSS technology, AUSGeoid09 can replace the need for traditional third-order levelling in many situations. Relative tests of AUSGeoid09 over a continent-wide set of over 20 million baselines showed that it can deliver better than Australian class LC levelling tolerances (12 ) in 99% of cases. The model accepts a user's GDA94 latitude, longitude and ellipsoidal height and returns an AHD height and deflections of the vertical. AUSGeoid09 is now available free-of-charge on the Geoscience Australia website (http://www.ga.gov.au/geodesy/ausgeoid/nvalcomp.jsp).
Product Type
nonGeographicDataset
eCat Id
71626
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Custodian
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
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- External Publication
- ( Theme )
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- gravity
- ( Theme )
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- geoscience
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2011-03-21T00:00:00
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geoscientificInformation
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