This report refers to the 5th Local Monitoring Survey completed at the Pohnpei (POHN) continuous GPS (CGPS) station on Saturday 15 August 2009

The gravitational attraction of the Galactic centre leads to the centrifugial acceleration of the Solar system barycentre. It results in secular aberration drift which displaces the position of the distant radio sources. The effect should be accounted for in high-precision astrometric reductions as well as by the corresponding update of the ICRS definition.

The national geodetic program in Australia is undertaken by the National Geospatial Reference System (NGRS) Section within Geoscience Australia. The NGRS is a continually evolving system of infrastructure implemented through the existing geodetic techniques such as Satellite Laser Ranging (SLR), Global Navigation Satellite Systems (GNSS) and Very Long Baseline Interferometry (VLBI). The NGRS serves the broader community by providing an accurate foundation for positioning, and consequently all spatial data, against which every position in Australia is measured and can be legally traced. In Australia, the sparsity of geodetic infrastructure has limited the developments of geodetic applications. For instance, the Geocentric Datum of Australia 1994 (GDA94) was based on observations (1992 - 1994) from a sparse network of Continuously Operating Reference Station (CORS) called the Australian Fiducial Network (AFN). Since that time the demand for higher accuracies has resulted in GDA94 no longer adequately serving user demand. The adoption of a fully dynamic datum will ensure that Australians can use positioning technology to its fullest capability, whereas at present when using GDA94 they are limited to the accuracy that was achievable in 1994 when GDA94 was created. Consequently, national infrastructure development programs, such as AuScope, have been implemented to improve the geodetic accuracies by contributing to the next generation of the Global Geodetic Observing System (GGOS). This presentation reviews the national geodetic activities in Australia, especially the AuScope program, a recent enhancement to the Australian geodetic infrastructure.

Geoscience Australia's involvement in Antarctica has primarily been focused on the maintenance and enhancement of geodetic infrastructure within the Australian Antarctic Territory (AAT). Such infrastructure provides a fundamental reference frame for the region and supports earth monitoring science applications on local, regional and continental scales. These foundations have furthered the development of geodesy throughout the continent and provided information on the contemporary motion of the Antarctic plate for comparison with long-term geological records. Primary Antarctic geodetic control also contributes to a greater understanding of global earth movement though contribution to the International Terrestrial Reference Frame solutions. This report focuses on the field work undertaken during the 2010/11 Antarctic summer by Geoscience Australia surveyors at the Davis, Mawson and Macquarie Island research stations, as well as several remote sites in Eastern Antarctica. At each of the research stations, upgrades and local monitoring surveys were performed at the continuously operating reference stations (CORS), which form part of the Australian Regional GNSS Network and also contribute to the International GNSS Service. Remote GPS sites in the Grove Mountains, Bunger Hills, Wilson Bluff and Mt Creswell were also visited for equipment upgrades and data retrieval. Additional surveys were undertaken directed at enhancing the spatial infrastructure around both the Larsemann and Vestfold Hills. Support was also provided to a number of different Australian Antarctic Division projects.

An application dated 08 October 2012 for verification of a reference standard of measurement under Regulation 12 of the National Measurement Regulations 1999 was received from the Goonyella Riverside Mine of the BHP Billiton Mitsubishi Alliance (BMA) for verification of GDA94 position on their owned or managed station monument. This report documents the processing and analysis of GPS data observed by the Goonyella Riverside Mine during a 7-day period from 30 September to 06 October 2012 (day of year 274 to 280) for the station GRBA to satisfy the position verification requirements.

An application dated 01 November 2012 for verification of a reference standard of measurement under Regulation 12 of the National Measurement Regulations 1999 was received from the Clermont Coal Mine of the Rio Tinto Coal Australia (RTCA) for verification of GDA94 position on their owned or managed station monument. This report documents the processing and analysis of GPS data observed by the Clermont Coal Mine during a 7-day period from 28 October to 03 November 2012 (day of year 302 to 308) for the station CCMB to satisfy the position verification requirements.

Australia, like most developed countries, is constantly driven by the need for improved accuracy, stability, and reliability of its geodetic products. These products underpin a variety of science endeavours, as well as an explosion of precise positioning applications for industrial and societal use. It is well understood that the strength of the Global Geodetic Observing System is obtained in two ways. The first is the continued refinement of the individual geodetic techniques (VLBI, SLR, GNSS etc); and the second is the improvement of the connection between those techniques at co-located sites, of which Australia now has five (Yarragadee, Mt Stromlo, Katherine, Hobart and Parkes). This presentation will explore efforts in Australia towards improving both of these elements. A comparison of local tie results to ITRF2008 will be given for Yarragadee in Western Australia. The residual error is comprised of around 10mm in GPS systematic error caused by the un-calibrated Antenna / Radome combination, several millimetres of survey error including site deformation, and up to 5mm combination technique error.

Gravity station location map, updated to October 2007

Geoscience Australia has recently conducted absolute gravity observations at Davis and Mawson stations in the Australian Antarctic Territory to establish accurate gravity reference points for past and future gravity surveys. These absolute gravity observations are the first such measurements undertaken at any of the Australian Antarctic stations and will not only provide an accurate absolute datum for future gravity work but will also enable gravity surveys that have already been conducted in the Australian Antarctic Territory to be tied to the same datum, thus allowing past and future gravity surveys to be accurately merged and combined.

The annual Asia Pacific Regional Geodetic Project (APRGP) GPS campaign is an important activity of the Geodetic Technologies and Applications Working Group (WG) of the Permanent Committee on GIS Infrastructure for Asia and the Pacific Region (PCGIAP). This document overviews the data analysis of the APRGP GPS campaign undertaken in 2010. The GPS data was processed using version 5.0 of the Bernese GPS Software in a regional network together with selected IGS (International GNSS Service) sites. The GPS solution was constrained to the ITRF2005 reference frame through adopting IGS05 coordinates on selected IGS reference sites and using the final IGS earth orientation parameters and satellite ephemerides products.