In February 2015, the Intergovernmental Committee on Mapping and Surveying (ICSM), Permanent Committee on Geodesy (PCG) proposed a revised roadmap to modernise the Geocentric Datum of Australia 1994 (GDA94), Australia’s current national Geocentric Datum. This report describes the information considered by the PCG prior to its determination of the revised proposal and develops recommendations for the implementation process for consideration by ICSM.

The first version of the Datum Modernisation Roadmap was released in 2011 in response to an assessment by PCG that GDA94 would eventually be unable to satisfy the requirements of all Australians. Simply, it was envisaged the reference system would need to be able to support the ability for spatial data sets on the national datum to be closely aligned with Global Navigation Satellite System (GNSS) derived International Terrestrial Reference Frame (ITRF) locations in real time and ultimately this would require implementation of a national time dependent reference frame.

Information taken into account by the PCG and outlined in the report includes feedback from consultation with the spatial sector between 2012 and 2014 on the first version roadmap, lessons learnt from an analysis of the GDA94 implementation that may be applied to current modernisation efforts, and the anticipated impact of the inevitable spread of ubiquitous accurate positioning within society. Consideration of current international responses to the provision of time dependent reference frames is also included.

Consultation with the spatial sector revealed general support for the effort to modernise GDA94 with the majority of stakeholders expressing the view that “Do Nothing” was not a realistic option. Respondents identified a range of issues associated with implementation of a modernised datum and emphasised the need for a nationally coordinated process. Overall, the feedback highlighted the importance of project and change management processes in ensuring a successful outcome, leading to the inclusion of a section specifically addressing these aspects in this narrative.

The report indicates that availability of ubiquitous accurate GNSS positioning is inevitable within Australia, driven by the natural evolution of GNSS systems and the presence of GNSS and other measurement sensors in smartphones and vehicles. A ‘tsunami’ of adoption is predicted whereby literally millions of Australians may utilise the technology within several years of its development. Failure to satisfy the requirements of these users is likely to result in confusion and conflict, as well as lost opportunities.

Seventeen general recommendations for the implementation process are developed and include:

• That ICSM and ANZLIC should determine and clearly document the intended datum modernisation pathway to provide a mandate for change.
• The formation of a project team to manage the implementation at a national level, using project and change management techniques and specifically addressing technical and practical aspects.
• Implementation should aim to enable spatial datasets to be readily represented in close alignment with the GNSS measurement frame (ITRF) at around 2020.
• The importance of targeted and general communication, including the provision of ‘soft’ educational resources to complement the ‘hard’ technical resources.
• The necessity to engage with commercial off-the-shelf software providers to facilitate the introduction of software tools that perform the appropriate datum transformations.

This report does not include a benefit-cost assessment of particular options for datum modernisation nor does it deal with the explicit content of the technical tools that will need to be provided.

The report can be downloaded from here.