Australian Height Datum and Geoid Models

Last updated:7 June 2023

Australian Height Datum - The Australian Height Datum (AHD) is the official national vertical datum for Australia and refers to Australian Height Datum 1971 (AHD71; Australian mainland) and Australian Height Datum (Tasmania) 1983 (AHD-TAS83).

AUSGeoid2020 - AUSGeoid2020 has been developed to support the improved determination of AHD height estimates HAHD from GNSS observations.

Differences between AUSGeoid09 and AUSGeoid2020 - The change in the reference frame used for the development of GDA2020 (i.e. ITRF2014 compared to ITRF92 used for GDA94) means the ellipsoidal height of a point in GDA94 is approximately 9 cm higher than GDA2020.

AGRS Tools, Models and Resources - The Australian Geospatial Reference System is managed by the Intergovernmental Committee on Surveying and Mappings’ Permanent Committee on Geodesy.