GDA2020 (Geocentric Datum of Australia 2020 | EPSG:7844)

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Introduction

GDA2020 is the latest geocentric coordinate reference frame launched by Australia in 2020. It is consistent with ITRF2014, providing the position and long-term velocity of the base station at the reference epoch, and includes the post-seismic deformation caused by large earthquakes and the annual and semi-annual parameter models. The accuracy of GDA2020 is improved compared to ITRF2014, and can meet the needs of high-precision geolocation and measurement.

Coordinate System Composition

Coordinate origin: The reference starting point of the coordinate system, usually associated with the center of mass of the earth, providing a reference position for subsequent coordinate calculations.
Coordinate axis: The spatial dimension is defined by a three-dimensional rectangular coordinate system, including the X axis (east-west direction), the Y axis (north-south direction) and the Z axis (vertical direction), which are used to quantify the position of spatial points.
Direction definition: The positive direction of the coordinate axis follows international standards, for example, the X axis points to the direction of the prime meridian, and the Z axis is parallel to the earth’s rotation axis, ensuring the consistency of the coordinate system direction.
Unit length: A unified length unit (such as meters) is used for distance measurement to ensure the comparability and accuracy of coordinate values in different regions.
Coordinate system type: As a geocentric coordinate reference frame, its coordinate calculation is based on the center of mass of the earth, consistent with ITRF2014, and supports high-precision geolocation needs.

Through the combination of the above elements, this coordinate system achieves an accurate description of the geographic spatial location of Australia and surrounding areas, providing a reliable foundation for applications such as engineering measurement and mapping.

Pros

High precision: GDA2020 has improved accuracy compared to previous reference frames and can meet the needs of high-precision geolocation and measurement.
Consistent with ITRF2014: GDA2020 is consistent with ITRF2014, which is convenient for aligning with international standards and promoting international cooperation and exchanges.
Contains multiple parameter models: GDA2020 not only provides the position and long-term velocity of the base station at the reference epoch, but also includes the post-seismic deformation caused by major earthquakes and the anniversary and semi-anniversary parameter models, which can more comprehensively reflect the movement of the earth.

Cons

Only applicable to Australia and surrounding areas: GDA2020 is a reference framework dedicated to Australia and may not be applicable or require conversion for other regions.
High technical threshold: Using GDA2020 requires certain professional knowledge and skills, which may be difficult for non-professionals to learn.

Application Scenario

GDA2020 is suitable for scenarios in Australia and surrounding areas that require high-precision geographic positioning and measurement, covering areas such as map making, geographic information system (GIS) data processing, engineering surveying (such as construction and road construction), and land planning and management, and can meet the needs of industries with strict requirements on geographic coordinate accuracy.

Example

Approximate shift from GDA94 to GDA2020 locations across Australia.

The National geodetic network used to establish and maintain GDA2020.