Asia-Pacific Reference Frame (APREF)

The purpose of the Asia-Pacific Reference Frame (APREF) project is to create and maintain an accurate geodetic framework to meet the growing needs of industries, science programs and the general public using positioning applications in the Asia-Pacific region.

Background of APREF

The use of positioning technology is growing rapidly in industries such as mining, agriculture and construction. Furthermore, in recent years, there has been an increasing demand from emergency services, hazard modellers, and land, utility and asset managers. The applications of these users have a demonstrated need for centimetre level or better geodetic infrastructure. In order to provide this, the Asia-Pacific region needs a consistent, continually refined and easily accessible reference frame.

In the Asia-Pacific region there are a substantial number of state-of-the-art Global Navigation Satellite System (GNSS) networks, which are commonly operated by national mapping agencies or private sector organisations. These networks represent an important and significant investment by the respective governments and industry in their own spatial infrastructure. However, when the Asia-Pacific region is viewed as a whole:

  • the infrastructure is comparatively sparse, inaccurate, and difficult to access when compared to other parts of the world such as Europe and the Americas
  • in general, the networks are not linked together, or to the global reference frame
  • the lack of data sharing impacts on the accuracy and type of geodetic analysis that can be performed.

It has become increasingly clear that the Asia-Pacific regional geodetic reference frame (crudely constructed as a patchwork of national and regional datums) is below the standard that it now available (and expected) in other regions, such as Europe and the Americas. As a consequence, this can be detrimental to regional scientific studies and national geodesy, leading to a loss in competitive advantage by nations in the Asia-Pacific region.

Recognising the importance of improving the regional geodetic framework, member countries of the 18th United Nations Regional Cartographic Conference for Asia and the Pacific (UNRCC-AP; October 2009, Bangkok), agreed to improve the reference frame in the Asia-Pacific region. APREF has already made some progress in developing the Asia-Pacific regional geodetic infrastructure; however, it can still be characterised as being a work in progress. APREF is a voluntary, collegial, non-commercial endeavour, and there is no central funding source, and participating organisations contribute their own resources.

Objectives of APREF

The broad objective of APREF is to create and maintain a densely realised and accurate geodetic framework, based on continuous observation and analysis of GNSS data. APREF addresses issues associated with the definition, realisation and maintenance of the Asia-Pacific Reference Frame.

In the short-term, the APREF project:

  • will encourage sharing of GNSS data from Continuously Operating Reference Stations (CORS) in the region
  • develop an authoritative source of coordinates, and their respective velocities, for geodetic stations in the Asia-Pacific region.

In the longer term, the APREF project:

  • will develop and maintain the APREF Permanent CORS Network, in close cooperation with International GNSS Service (IGS)
  • improve the contribution of APREF sites to the International Terrestrial Reference Frame (ITRF)
  • provide more infrastructure to support geodetic projects
  • establish a dense velocity field model in Asia and the Pacific for scientific applications and the long-term maintenance of the Asia-Pacific reference frame
  • organise regular symposia addressing activities carried out at national and regional levels related to the work and objectives of APREF.

APREF organisational structure

The APREF project consists of:

  • Steering Committee - responsible for the policy development of the APREF
  • Central Bureau
  • Network operators
  • Data centres
  • Analysis centres.

Currently, the APREF Steering Committee includes:

  • John Dawson, Australia (Chair)
  • Shigeru Matsuzaka, Japan
  • Hanjiang Wen, China
  • Cecep Subarya, Indonesia
  • Hadi Vaezi, Iran
  • Chris Rizos, International Association of Geodesy (IAG).

The Chair of the APREF Steering Committee, John Dawson from Geoscience Australia, represents APREF officially, and has the role of disseminating information, maintaining a list of contacts, and maintaining the APREF website.

The Central Bureau, within Geoscience Australia, functions as the ¿¿¿day-to-day¿¿¿ APREF coordinating body. Specifically, the Central Bureau ensures that APREF products are made available to the global geodetic community. Furthermore, they are the combination centre responsible for analysing, combining and validating the individual solutions of the contributing Analysis Centres, and for expressing the combined solution in the ITRF. The APREF project already has three Analysis Centres: Geoscience Australia, the Curtin University of Technology, and the University of New South Wales.

Participating agencies

In response to the March 2010 Call for Participation, a large number of agencies have agreed to participate in APREF, Table 1 summarises their commitments.

Table 1: Responses to the APREF Call For Participation. Responding agencies have indicated whether they would undertake analysis, provide data archive and product distribution or supply data from GNSS stations (as of 17 February 2013)
Country/Locality Responding Agency Proposed Contribution
Analysis Archive Stations
Afghanistan National Geospatial-Intelligence Agency, USA 2
Alaska, USA National Geodetic Survey (USA) 90
American Samoa National Geodetic Survey (USA) 1
Australia Geoscience Australia x x 97
Australia Curtin University of Technology x 1
Australia University of New South Wales x 1
Australia Department of Environment and Resource Management, Queensland 10
Australia Department of Sustainability and Environment, Victoria x 55
Australia Department of Lands and Planning, Northern Territory 5
Australia Department of Primary Industries, Parks, Water & Environment, Tasmania 2
Australia Radio and Space Weather Services, Bureau of Meteorology 3
Australia Land and Property Management Authority, New South Wales 89
Brunei Survey Department, Negara Brunei Darussalam 1
Cook Islands Geoscience Australia 1
Cook Islands Geospatial Information Authority of Japan 1
Ethiopia Ethiopian Mapping Agency 3
Federated States of Micronesia Geoscience Australia 1
Fiji Geoscience Australia 1
French Polynesia Geospatial Information Authority of Japan 1
Guam, USA National Geodetic Survey (USA) 1
Hawaii, USA National Geodetic Survey (USA) 19
Hong Kong, China Survey and Mapping Office 7
Indonesia Bakosurtanal 4
Iran National Cartographic Center, Iran 6
Iraq Iraqi Ministry of Water Resource General Directorate for Survey 6
Japan Geospatial Information Authority of Japan x x 10
Kazakhstan Kazakhstan Gharysh Sapary 2
Kiribati Geoscience Australia 1
Kiribati Geospatial Information Authority of Japan 2
Macau, China Macao Cartography and Cadastre Bureau 3
Manus Island Geoscience Australia 1
Marshall Islands Geoscience Australia 1
Micronesia Geoscience Australia 1
Mongolia Administration of Land Affairs, Construction, Geodesy and Cartography (ALACGaC) 8
Nauru Geoscience Australia 1
New Zealand Land Information New Zealand x x 38
Northern Mariana Islands National Geodetic Survey (USA) 1
Papua New Guinea National Mapping Bureau, Papua New Guinea, and Geoscience Australia 2
Philippines Department of Environment and Natural Resources, National Mapping and Resource Information Authority x x 4
Samoa Geoscience Australia 1
Solomon Islands Geoscience Australia 1
Tonga Geoscience Australia 1
Tuvalu Geoscience Australia 1
Vanuatu Geoscience Australia 1

Data and products

APREF data and products contributed to and generated by the APREF project are provided with an open access data policy via the internet following the practice of the IGS.

How can I participate in APREF?

APREF encourages participation from organisations active in the Asia-Pacific region who are prepared to, on an ongoing basis (at least two years):

  • provide GNSS data from CORS Stations
  • provide access and on-line archiving of APREF data and products for users; and/or
  • routinely analyse some, or all, of the APREF GNSS CORS data, providing station coordinate estimates.

To participate in APREF, the responding agencies should write a Letter of Intent to

APREF Central Bureau
Dr John Dawson
Earth Monitoring Group
Geoscience Australia
GPO Box 378 Canberra ACT 2601 Australia

Telephone: +61 2 6249 9028
Fax: +61 2 6249 9969
Email: John.Dawson@ga.gov.au

This Letter of Intent should include the following information:

  • organisation name and address
  • name, address and contact details of the primary and secondary points of contact within the contributing organisation
  • specific details of the organisation¿¿¿s proposed contribution to APREF.

Station and data standards

If possible APREF CORS stations should meet the standards of the IGS. For further details see IGS Site Guidelines.

Critically, each network operator must assure that contributed stations will operate for at least two years. Furthermore, station metadata such as receiver and antenna information is a mandatory requirement for participation in the APREF project. For further details see site information form.

All GNSS data should be made available in RINEX format at a 30-second sampling rate and where available, participants may also submit broadcast ephemeris and meteorological RINEX files. Contributions of Regional Navigation Satellite Systems (RNSS) data are also most welcome. See Guidelines for APREF Station Operators for details.

Analysis standards

For those organisations wanting to contribute solutions, the analysis must be to the standard consistent with the IERS Conventions 2003 (for example using the Bernese, GIPSY, GAMIT, NAPEOS, EPOS, PAGES software packages). For further details see IERS Conventions Center.

Contributed solutions are in the SINEX format.

APREF mandate

APREF was mandated by Resolution 1 (Regional Geodesy) of the 18th United Nations Regional Cartographic Conference (UNRCC) for Asia and the Pacific, 26 ¿¿¿ 29 October 2009, Bangkok, Thailand. APREF is also endorsed by the: International GNSS Service (IGS), United Nations Office for Outer Space Affairs (UNOOSA), and the Federation of International Surveyors (FIG).