The integrity and strength of multi-technique terrestrial reference frames, such as realisations of the International Terrestrial Reference Frame (ITRF), depend on the precisely measured and expressed local-tie connections between space geodetic observing systems at co-located observatories. Australia has several observatories which together host the full variety of space geodetic observation techniques, including Global Navigation Satellites Systems (GNSS), Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR) and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) beacons.
This report documents the technical aspects of the survey undertaken to determine the local-tie connections at the Katherine VLBI Observatory. The Observatory is located at the Charles Darwin University campus near Katherine in the Northern Territory. The Observatory has a 12 m radio telescope that is used for VLBI, co-located with two permanent GNSS sites, one of which contributes to the International GNSS Service (IGS) network. The survey was conducted in July 2010 by surveyors from Geoscience Australia. Precision classical geodetic observations were combined with geodetic GNSS observations to determine for the first time the relationship between the VLBI system invariant point (IVP) and the conventional reference points of the GNSS antennas and the surrounding survey control.
The results of this survey have been provided to the International Earth Rotation Service (IERS) for inclusion in the next realisation of the ITRF.
