A comparison of AUSGeoid09 and AUSGeoid98 in the Hawkesbury Valley

Marion, Michael (2011) A comparison of AUSGeoid09 and AUSGeoid98 in the Hawkesbury Valley. [USQ Project]


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Horizontal coordinates in Australia are defined by the Geocentric Datum of Australia (GDA94) which is based on a global geodetic datum that has been established to facilitate the use of Global Navigational Satellite Systems (GNSS), however the Australian Height Datum (AHD), a mean sea level based datum has been retained to define vertical position. This is because the reference ellipsoid used by space based measurement systems cannot properly describe the flow of fluids as it is not related to gravity. A geoid model representing a surface of equal gravity is needed to transform GNSS heights onto the gravity based AHD. In March of 2011 Geoscience Australia released a new geoid model known as AUSGeoid09 to replace the existing AUSGeoid98. This model has been developed with the specific aim of giving GNSS users a more accurate means of determining AHD heights.

A study has been conducted to establish the accuracy of AHD heights generated using AUSGeoid09 and AUSGeoid98 within a test area of the Hawkesbury Valley NSW. Using published AHD heights as the standard for comparison, the accuracy of each model has been assessed to gauge the level of improvement if any, gained by the use of AUSGeoid09.
The results show a significantly better determination of AHD using AUSGeoid09 within the test site, using the equipment and methods adopted by this study. However the level of improvement is not consistent throughout the test area. It was found that AUSGeoid09 did not improve the accuracy of the AHD heights generated along the escarpment of the Great Dividing Range.

This research draws attention to the need for GNSS users to have an understanding of the performance and limitations of the geoid models they use in order to make sensible decisions regarding their use.

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Item Type: USQ Project
Refereed: No
Item Status: Live Archive
Additional Information: Bachelor of Spatial Science (Surveying) project.
Faculty/School / Institute/Centre: Historic - Faculty of Engineering and Surveying - Department of Surveying and Land Information (Up to 30 Jun 2013)
Supervisors: Gibbings, Peter
Date Deposited: 20 Dec 2012 06:52
Last Modified: 19 Jul 2018 00:23
Uncontrolled Keywords: AUSGeoid09, AUSGeoid98, AHD height
Fields of Research (2008): 09 Engineering > 0909 Geomatic Engineering > 090906 Surveying (incl. Hydrographic Surveying)
09 Engineering > 0909 Geomatic Engineering > 090903 Geospatial Information Systems
Fields of Research (2020): 40 ENGINEERING > 4013 Geomatic engineering > 401306 Surveying (incl. hydrographic surveying)
40 ENGINEERING > 4013 Geomatic engineering > 401302 Geospatial information systems and geospatial data modelling
URI: http://sear.unisq.edu.au/id/eprint/22557

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