Performance of AUSGeoid09 in mountainous regions
Paper
Paper/Presentation Title | Performance of AUSGeoid09 in mountainous regions |
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Presentation Type | Paper |
Authors | Sussanna, Vittorio (Author), Janssen, Volker (Author) and Gibbings, Peter (Author) |
Editors | Janssen, Volker |
Journal or Proceedings Title | Proceedings of the 22nd Association of Public Authority Surveyors Conference (APAS2017) |
Number of Pages | 18 |
Year | 2017 |
Place of Publication | New South Wales, Australia |
Web Address (URL) of Paper | https://www.apas.org.au/apas2017 |
Conference/Event | 22nd Association of Public Authority Surveyors Conference (APAS2017) |
Event Details | 22nd Association of Public Authority Surveyors Conference (APAS2017) Parent Association of Public Authority Surveyors Conference (APAS) Delivery In person Event Date 20 to end of 22 Mar 2017 Event Location Shoal Bay, Australia |
Abstract | The Australian Height Datum (AHD) is our current national vertical datum, and AUSGeoid09 is the current quasigeoid model used to compute (normal-orthometric) AHD heights from Global Navigation Satellite System (GNSS) derived ellipsoidal heights given in the Geocentric Datum of Australia 1994 (GDA94). While previous studies have evaluated the AUSGeoid09 model across Australia, these have generally not focused on mountainous regions in particular. This paper investigates the performance of AUSGeoid09 in the Mid Hunter and Snowy Mountains regions of New South Wales, from a user’s perspective. Comparisons are undertaken in an absolute sense (i.e. single point) and relative sense (i.e. height difference between two points) between AUSGeoid09-derived heights and official AHD heights on public record. The performance of AUSGeoid09 is evaluated relative to its predecessor AUSGeoid98. In both study areas, an overall improvement is evident when applying AUSGeoid09 to compute AHD heights. However, a slope was detected for AUSGeoid09 residuals in the Snowy Mountains, and it appears that the geometric component may have overcompensated for sea surface topography in this area. AUSGeoid09 generally provided AHD height differences at the ±0.05 m to ±0.09 m level (1 sigma) and substantially increased the percentage of GNSS-derived height differences meeting third-order differential levelling specifications. This is a very encouraging result, considering the difficulties of spirit levelling in mountainous terrain and the increasing popularity of GNSS-based height transfer in practice. However, it has been shown that some discrepancies still remain between AUSGeoid09-derived heights and AHD. It is anticipated that the new AUSGeoid2020 (to be used in conjunction with GDA2020 ellipsoidal heights) will substantially improve access to AHD via GNSS techniques. The methodology presented in this paper will be very beneficial in regards to future testing of AUSGeoid2020. |
Keywords | AUSGeoid09, AHD, geoid model, N values, GNSS, national datums |
ANZSRC Field of Research 2020 | 379999. Other earth sciences not elsewhere classified |
Public Notes | © 2017 Association of Public Authority Surveyors New South Wales Inc. |
Byline Affiliations | Department of Finance, Services and Innovation, New South Wales |
Faculty of Health, Engineering and Sciences | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q3z13/performance-of-ausgeoid09-in-mountainous-regions
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