The keynote of the tenth GM is the contribution of the VLBI Global Observing System
(VGOS) to the Global Geodetic Observing System (GGOS) in its endeavor to render
sustainable development possible under the theme
“Global Geodesy and the Role of VGOS – Fundamental to Sustainable Development.”
The United Nations recognized the
importance of geospatial information to address global challenges with creating
a UN-GGIM Subcommittee on Geodesy and following through with a roadmap to implement
a Global Geodetic Reference Frame (GGRF). The space-geodetic techniques of VLBI,
GPS, SLR, and DORIS will be fundamental for an accurate, accessible and sustainable
GGRF to support science and society.
Building the VGOS networkS1
Conveners: Pablo de Vicente and Guangli Wang
VGOS is the new VLBI network, evolving under the auspices of the IVS, that is expected to provide unprecedented accuracies for station positions (1 mm) and station velocities (0.1 mm/yr), continuous observational time series for station positions and Earth orientation parameters, and fast turnaround time from observation to geodetic results. These features will foster new science and applications. In this session we will concentrate on the evolution of the network and the technological developments. Network topics may include, but are not limited to, reports on new sites and new telescopes as well as simulations of expected performance. The technology developments for VGOS may cover digital backends, recording systems, e-VLBI, RFI excision techniques, and automation of operations, among others.
VGOS technique and observationsS2
Conveners: Chet Ruszczyk and Alexander Neidhardt
The VGOS network of next-generation VLBI antennas continues to grow. The new network is expected to provide unprecedented accuracies for station positions (1 mm) and station velocities (0.1 mm/yr), continuous observational time series for station positions and Earth orientation parameters, and fast turnaround time from observation to geodetic results, fostering new science and applications. This session will concentrate on the observing strategies and their implementation. This may include, but is not limited to, general papers on the VGOS strategies, the implementation of new observation techniques, new schedule generation algorithms, VGOS correlation and fringe fitting, VGOS data structures, and VGOS test sessions and results. Presentations may also address the effect of the operational load of VGOS on stations, correlators, and data transfer.
Legacy S/X and mixed legacy/VGOS operationsS3
Conveners: David Hall and Evgeny Nosov
This session focuses on the present and near-term future activities at VLBI network stations and correlators, including status reports of the legacy stations and correlators. In addition, we solicit presentations about issues that relate to improving VLBI data quality in general. The near-term future topics could cover presentations about strategies for the transition from the current network to the VGOS network, such as mixed-mode observations and other legacy-to-VGOS local tie procedures, network compatibilities, and investigations of the effect of station conversions to VGOS broadband onto the legacy network. Furthermore, we welcome submissions concerning the GGOS project's contributions to local surveys to determine the spatial vectors from the radio telescopes to co-located geodetic instruments.
VLBI core products and their improvementsS4
Conveners: John Gipson and Oleg Titov
The analysis of VLBI observations produces time series, long-term average positions and rates, and values of physical parameters. We seek contributions in topics such as the use of VLBI results in modeling geophysical fluids from the atmosphere to the core, improvement of the precession-nutation model, investigation of the Earth rotation variations at different time scales (from minutes to decades), inner and outer core nutations, refinement of the terrestrial and celestial reference frames, detection and interpretation of the motions of specific sites and radio sources, atmospheric studies (both the troposphere and the ionosphere), relativity tests, and other scientific uses of geodetic and astrometric VLBI data and their impact on astrophysics and cosmology. As 2018 will see the release of a new realization of the celestial reference frame (ICRF3), we welcome presentations on individual solutions provided by the IVS analysis centers to the ICRF3 effort as well as their combinations. Other important topics are the comparison, validation, and combination of VLBI with other space-geodetic techniques, and the integration of the techniques within the framework of IAG’s Global Geodetic Observing System (GGOS). Special attention is expected to be given to the assessment of the actual accuracy and systematic errors of the VLBI-derived results, and, in particular, to the errors caused by deficiencies of the models used in data processing.
Extending the scope of VLBI usage/applicationsS5
Conveners: Lucia McCallum and Thomas Hobiger
In this session we seek contributions related to new ideas for VLBI observations, including new targets or frequencies, combination and comparisons with other techniques, as well as all other related activities such as outreach, teaching, and promotion of VLBI. VLBI is the only space-geodetic technique that precisely measures positions of distant sources at radio frequencies. It is the current fundamental technique for the realization of the ICRF. With the first results of the GAIA mission, a competitive realization at optical wavelengths will be available in the coming years, which has to be linked to the ICRF in the radio domain. We encourage contributions on the radio-optical link as well as on VLBI at non-standard frequencies such as K, Ka, and Q and W bands, and their potential benefits in studies of source structure and core shift.
The ITRF is based on data from all four space-geodetic techniques (GNSS, SLR, DORIS, and VLBI). The somewhat independent generation of the two frames (CRF and TRF) may result in inconsistencies of the two frames, which potentially impacts the interlinking Earth Orientation Parameters (EOP). Hence, we also seek contributions about new ideas for the VLBI technique to detect systematic errors and to improve the interrelation with other techniques. This includes VLBI observations of satellites (e.g., GNSS satellites or dedicated co-location satellites) and improved combination techniques.
Lastly, this session allows for contributions beyond the more traditional scope of VLBI to quasars. This may comprise progress in observations to other targets, such as pulsars or interplanetary spacecraft, and using VLBI to measure new quantities. Furthermore, with VLBI observatories constituting significant research facilities, we also welcome examples of VLBI-related applications beyond science; for instance, its impact on the national and global high-speed datalink infrastructure or on the development of polar regions.