In 1994, the United Nations Regional Cartographic Conference for Asia and the Pacific resolved to establish a Permanent Committee comprising of national surveying and mapping agencies to address the concept of establishing a common geographic information infrastructure for the region. This resolution subsequently led to the establishment of the Permanent Committee for GIS Infrastructure for the Asia and Pacific (PCGIAP). One of the goals of the PCGIAP was to establish and maintain a precise understanding of the relationship between permanent geodetic stations across the region. To this end, campaign-style geodetic-GPS observations, coordinated by Geoscience Australia, have been undertaken throughout the region since 1997. In this presentation, we discuss the development of an Asia Pacific regional reference frame based on the PCGIAP GPS campaign data, which now includes data from 417 non-IGS GPS stations and provides long term crustal deformation estimates for over 200 GPS stations throughout the region. We overview and evaluate: our combination strategy with particular emphasis on the alignment of the solution onto the International Terrestrial Reference Frame (ITRF); the sensitivity of the solution to reference frame site selection; the treatment of regional co-seismic and post-seismic deformation; and the Asia-Pacific contribution to the International Association of Geodesy (IAG) Working Group on "Regional Dense Velocity Fields". The level of consistency of the coordinate estimates with respect to ITRF2005 is 6, 5, 15 mm, in the east, north and up components, respectively, while the velocity estimates are consistent at 2, 2, 6 mm/yr in the east, north and up components, respectively.

The IAG Working Group (WG) 'Integration of Dense Velocity Fields in the ITRF' was created in 2011 as follow-up of the WG 'Regional Dense Velocity Fields' (2007-2011). The goal of the WG group is to densify the ITRF (International Terrestrial Reference Frame) using regional GNSS solutions as well as global solutions. This was originally done by combining several cumulative position/velocity solutions as well as their residual position time series submitted to the WG by the IAG regional reference frame sub-commissions (APREF, EUREF, SIRGAS, NAREF) and global (ULR) analysis centers. However, several test combinations together with the comparison of the residual position time series demonstrated the limitations of this approach. In June 2012, the WG decided to adopt a new approach based on a weekly combination of the GNSS solutions. This new approach will mitigate network effects, have a full control over the discontinuities and the velocity constraints, manage the different data span and derive residual position time series in addition to a velocity field. All initial contributors have agreed to submit weekly solutions and in addition initial contacts have been made with other sub-commissions particularly Africa in order to extent the densified velocity field to all continents. More details on the WG are available from http://epncb.oma.be/IAG/.

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.

Ongoing developments in geodetic positioning towards greater accuracies with lower latency are now allowing the measurement of the dynamics of the Earth's crust in near real time. However, in the Australian circumstance a sparsity of geodetic infrastructure has limited the application of modern, geodetic science to broader geoscience research programs. Recent enhancements to the Australian geodetic infrastructure, through the AuScope initiative, offer opportunities for research into refinement of geodetic accuracies, as well as their application to measuring crustal deformation.

Applications dated 18 August 2010 for verification of a reference standard of measurement under Regulation 12 of the National Measurement Regulations 1999 was received from the Land and Property Management Authority, NSW for verification of GDA94 position on their CORSnet monuments. This report documents the processing and analysis of GPS data observed by the CORSnet-NSW GPS stations during a 7-day period from 08 August to 14 August 2010 (day of year 220 to 226) for 4 stations (CSNO, IHOE, PBOT, and TBOB) to satisfy the position verification requirements.

Australia is a large continent with a relatively low population which is highly dependent on the mining, agricultural and transport industries for economic prosperity. These industries are themselves increasingly dependent on having access to high-quality geodetic infrastructure, especially when seeking operating efficiencies. Australia is also surrounded to the north and east by some of the most seismically active zones in the world, and is geographically isolated by the Indian, Pacific and Southern Oceans. This combination of characteristics creates some interesting challenges for the Australian Government in maintaining, developing and delivering a stable reference frame as a platform upon which a precise positioning capability can be established for science and society more generally. This presentation will detail recent GGOS related efforts in Australia to improve the accuracy of the International Terrestrial Reference Frame (ITRF). It will also discuss crustal deformation monitoring programs that allow ITRF based precise positioning services to be used in areas where localized deformation is not detected by existing GGOS infrastructure. Lastly, the presentation will also summarise efforts currently underway to enhance the provision of access to the ITRF anywhere, anytime across the Australian landmass in real time.

In a collaborative effort with the regional sub-commissions within IAG sub-commission 1.3 'Regional Reference Frames', the IAG Working Group (WG) on 'Regional Dense Velocity Fields' (see http://epncb.oma.be/IAG) has made a first attempt to create a dense global velocity field. GNSS-based velocity solutions for more than 6000 continuous and episodic GNSS tracking stations, were proposed to the WG in reply to the first call for participation issued in November 2008. The combination of a part of these solutions was done in a two-step approach: first at the regional level, and secondly at the global level. Comparisons between different velocity solutions show an RMS agreement between 0.3 mm/yr and 0.5 mm/yr resp. for the horizontal and vertical velocities. In some cases, significant disagreements between the velocities of some of the networks are seen, but these are primarily caused by the inconsistent handling of discontinuity epochs and solution numbers. In the future, the WG will re-visit the procedures in order to develop a combination process that is efficient, automated, transparent, and not more complex than it needs to be.

The Mt Pleasant Observatory is located near Hobart in Tasmania, Australia. The radio telescope, which is used for Very Long Baseline Interferometry (VLBI), is co-located with the permanent International GPS Service (IGS) GPS site (HOB2). A local tie survey at Mt Pleasant was completed in March 2002 by specialist Geoscience Australia Geodetic Surveyors using precision classical geodetic observations and geodetic GPS observations. The purpose of this survey was to repeat the determination of the relationship between the VLBI invariant reference point (7242 A 50116S002), the GPS reference point (HOB2 A 50116M004), and the surrounding survey control. This type of local tie survey has previously been undertaken at Mt Pleasant in 1995. This document reports on aspects of this survey.

The combination of Space Geodetic techniques is fundamental to the definition of the International Terrestrial Reference Frame (ITRF). An integral component of this combination is the accurately measured and expressed connection between the different space geodetic techniques, commonly referred to as the local tie. Our ambition is to observe each local tie at an accuracy level of 1-2 mm. The Yarragadee (Moblas 5) Satellite Laser Ranging (SLR) observatory, located in Western Australia, is co-located with permanent GPS, DORIS and GLONASS systems. A local tie survey at Yarragadee was completed over four days, the 24th to 27th November 2003, by specialist Geoscience Australia geodetic surveyors using precision classical geodetic observations and geodetic GPS observations. The purpose of this survey was to repeat the determination of the relationship between each of the observing techniques to the surrounding survey control. This survey also connected the new DORIS antenna position, YASB 50107S011, into the existing control, along with its pillar reference point, YASM 50107M007. This type of local tie survey has previously been undertaken at Yarragadee in 1992, 1999 and 2001. The 2003 survey results are compared with those observed at Yarragadee in 1999 and 2001. The results indicate a significant movement vertically, 4 to 5 mm, at RM3 and YAR2 50107M004 between the 1999 survey and the 2003 survey. The motion is not present to the same extent between the 2001 and 2003 surveys, indicating the displacement took place between the 1999 and 2001 surveys.

This report gives an overview about activities of the Geoscience Australia IVS Analysis Center during 2010