Sibling Radio Telescopes for Geodesy

The upcoming VLBI2010 Geodetic Observing System (VGOS) has the potential to improve the performance of geodetic Very Long Baseline Interferometry (VLBI) by about an order of magnitude. The concept includes co-located radio telescopes, either as two identical twin-telescope dishes or as a sibling telescope, a combination of a large legacy telescope and a new small VGOS antenna. Common observations at one site require new observing modes to be developed, but it also offers new analysis options for improved results. In addition, both telescopes need to be accurately connected to each other. The so-called local tie is essential to connect the present VLBI reference frame to the new VGOS frame, as well as to connect VLBI to the other space geodetic techniques making up the International Terrestrial Reference Frame (ITRF). In project Sibling Telescopes, observations with the Australian AuScope VLBI array, a prototype of the future VGOS system, will be used to optimise observing with sibling telescopes. This comprises new scheduling strategies, improved analysis, and the generation of actual results for the Ho (26m) - Hb (12m) antenna pair in Hobart. Improved planning of the observations will be developed using thorough simulations, answering the question whether it is better to observe the same source or different sources with the sibling telescope. Applying the developed scheduling tool, observations will be planned for the AUSTRAL observing program, using telescopes in Australia, New Zealand, and South Africa. In the analysis of the collected data common parameters will be combined. These are the identical troposphere above the sibling telescope, the parameters of the atomic clock at the station providing the frequency standard to both telescopes, and large-scale antenna movements due to plate tectonics and geodynamical processes. Special attention will be given to the determination of the local tie between the two radio antennas and the comparison between the solution from the VLBI observations and the tie vector determined by local surveying. Precise intra- technique ties will help to improve the inter-technique ties to the other co-located geodetic space techniques, the backbone of the ITRF as a multi-technique solution. The project Sibling Telescopes will be conducted at the University of Tasmania, operating the Australian AuScope VLBI array. The frequent AUSTRAL sessions offer the perfect test bed for the proposed research. During the return phase at the Vienna University of Technology, the findings will be extended to global networks. The developed tools and strategies will allow the optimal usage of the collected data as well as of the upcoming VGOS system, a global multi-million Euro research infrastructure project, targeted to fulfill future scientific and societal demands on Geosciences.

No additional funding sources recorded.