Conveners
Oral5: Geodetic and Astrometric Results: Part 1
- Stanislav Shabala (University of Tasmania)
- Johannes Boehm (Technische Universität Wien)
Oral5: Geodetic and Astrometric Results: Part 2
- Johannes Boehm (Technische Universität Wien)
- Stanislav Shabala (University of Tasmania)
Oral5: Geodetic and Astrometric Results: Part 3
- Stanislav Shabala (University of Tasmania)
- Johannes Boehm (Technische Universität Wien)
Oral5: Geodetic and Astrometric Results: Part 4
- Stanislav Shabala (University of Tasmania)
- Johannes Boehm (Technische Universität Wien)
Oral5: Geodetic and Astrometric Results: Part 5
- Johannes Boehm (Technische Universität Wien)
- Stanislav Shabala (University of Tasmania)
Sabine Bachmann
(BKG)
16/03/2016, 12:25
5: Geodetic and Astrometric VLBI Results
Oral Presentation
Generating the contribution of the International VLBI Service for Geodesy and Astrometry (IVS) to the ITRF2014 was the main task of the IVS Combination Center at the Federal Agency for Cartography and Geodesy (BKG, Germany) in 2015. Starting with the ITRF2005, the IVS contribution to the ITRF is an intra-technique combined solution using multiple individual contributions from different...
Dr
Richard Gross
(Jet Propulsion Laboratory)
16/03/2016, 14:00
5: Geodetic and Astrometric VLBI Results
Oral Presentation
KALREF, JPL's KALman filter and smoother for REference Frames, has been used to produce JTRF2014, a combined terrestrial reference frame determined from the input SINEX files submitted by the IVS, IGS, ILRS, and IDS for ITRF2014. Using a Kalman filter and smoother allows the reference frame to be determined sequentially as a time series. Incorporating process noise, determined from geophysical...
Mr
Benedikt Soja
(GFZ German Research Centre for Geosciences)
16/03/2016, 14:15
5: Geodetic and Astrometric VLBI Results
Oral Presentation
Terrestrial reference frames (TRF) of high quality are indispensable for many geoscientific and geodetic applications including very long baseline interferometry (VLBI) data analysis. While secular station coordinate changes, e.g. due to tectonic plate motion, can be well represented by a linear model, current accuracy requirements also demand modeling of non-linear signals such as surface...
Ms
Claudia Flohrer
(ESOC - Navigation Support Office, Darmstadt, Germany)
16/03/2016, 14:30
5: Geodetic and Astrometric VLBI Results
Oral Presentation
ESOC’s Navigation Support Office is providing the geodetic reference for ESA missions and as leader of the Galileo Geodetic Service Provider (GGSP) consortium, also for Galileo. The Navigation Support Office has demonstrated its expertise in the processing of various space-geodetic techniques, such as GNSS, SLR and DORIS and their combination on the observation level. Nevertheless, the last...
Dr
Younghee Kwak
(Technische Universität Wien)
16/03/2016, 14:45
5: Geodetic and Astrometric VLBI Results
Oral Presentation
Unlike CONT11, CONT14 does not have official information on common frequency standards for co-location sites. Nevertheless, according to Kwak et al. (2015), we have a possibility to find the co-located sites, which used the same clocks, through comparing clock rates from single technique solutions. Moreover, CONT14 includes co-located VLBI radio telescopes, i.e. HOBART26 and HOBART12....
Dr
Patrick Charlot
(Laboratoire d'Astrophysique de Bordeaux)
16/03/2016, 15:00
5: Geodetic and Astrometric VLBI Results
Oral Presentation
The ICRF3, the next realization of the International Celestial Reference Frame, is going to be built within the next two years for approval at the IAU 2018 General Assembly. This timescale is driven by the forthcoming optical reference frame to be built by the Gaia mission and aligned at best with the ICRF3. The ICRF3 work is carried out by an IAU Working Group set up in 2012. While the work...
Dr
Chopo Ma
(NASA Goddard Space Flight Center)
16/03/2016, 15:25
5: Geodetic and Astrometric VLBI Results
Oral Presentation
The Second Realization of the International Celestial Reference Frame (ICRF) used dual-frequency VLBI data acquired for geodetic and astrometric purposes from 1979-2009 by organizations coordinated by the IVS and various precursor networks. Since 2009 the data set has been significantly broadened, especially by observations in the Southern Hemisphere, and modeling of astronomical, geophysical...
Mr
David Mayer
(Technische Universität Wien)
17/03/2016, 09:00
5: Geodetic and Astrometric VLBI Results
Oral Presentation
The current realisation of the celestial reference frame, the ICRF2, was published 2009. Since then the VLBI technique evolved. New stations were implemented and the amount of data from the Southern Hemisphere increased dramatically. The demands on accuracy of the celestial reference frame are higher than ever, with the GAIA mission providing a catalogue in the visible spectrum with comparable...
Dr
David Gordon
(NVI Inc./GSFC)
17/03/2016, 09:15
5: Geodetic and Astrometric VLBI Results
Oral Presentation
The current state of the X/S source catalog is presented
and compared to ICRF2. There are currently ~60% more observations
and ~30% more sessions than were used for ICRF2. An ICRF made
today would have ~20% more sources than ICRF2 and the average inflated
formal errors would be ~2.4 times better than ICRF2. Much of this
improvement has come from the VCS-II campaign on the VLBA, in
which...
Mr
Andreas Iddink
(Institute of Geodesy and Geoinformation, University of Bonn)
17/03/2016, 09:30
5: Geodetic and Astrometric VLBI Results
Oral Presentation
One of the primary goals of VLBI is the determination of a CRF. Currently the third realization of the internationally adopted CRF, the ICRF3, is under preparation. In this process, various optimizations are planned to realize a CRF which does not only benefit from the increased number of observations. For instance, various campaigns have been performed to sample the southern hemisphere with a...
Dr
Karine Le Bail
(NVI, Inc.)
17/03/2016, 09:45
5: Geodetic and Astrometric VLBI Results
Oral Presentation
ICRF2 was adopted by the IAU in 2009 and was based on the position of 3414 radio sources determined by VLBI. Discussions on the next realization of the ICRF (ICRF3) have been underway within the IAU and IVS since 2012. VLBI has made significant advances since ICRF2.
From the latest GSFC solution, we extract a set of sources that defines a stable celestial reference frame, as shown by M....
Mr
César GATTANO
(SYRTE - Observatoire de Paris)
17/03/2016, 10:00
5: Geodetic and Astrometric VLBI Results
Oral Presentation
In a previous study, we characterized radio sources observed by Very Long Baseline Interferometry by different criteria in both radio and optical domains (see the abstract "VLBI sources in optical
and radio"). On the basis of the data derived from this study, we constructed several celestial reference frames by choosing a set of defining sources and studied their stability by two ways,...
Mr
Christopher Jacobs
(JPL/NASA)
17/03/2016, 10:15
5: Geodetic and Astrometric VLBI Results
Oral Presentation
Observations at X/Ka-band are motivated by their ability to access more compact source morphology and reduced core shift relative to observations at the historically standard S/X-band. In addition, the factor of four increase in interferometer resolution at Ka-band should resolve out some wide binary black holes which are a topic of concern
for AGN centroid stability.
Given these...
Dr
Maria Karbon
(GFZ)
17/03/2016, 10:30
5: Geodetic and Astrometric VLBI Results
Oral Presentation
Usually celestial radio sources in the celestial reference frame (CRF) catalog are divided in three categories: defining, special handling, and others. The defining sources are those used for the datum realization of the celestial reference frame, i.e. they are included in the No-Net-Rotation (NNR) constraints to maintain the axis orientation of the CRF, and are modeled with one set of totally...
Mr
Sayan Basu
(University of South Africa and Hartebeesthoek Radio Astronomy Observatory, South Africa)
17/03/2016, 11:15
5: Geodetic and Astrometric VLBI Results
Oral Presentation
The International Celestial Reference Frame (ICRF) are constructed using catalogs of extragalactic radio source (mainly quasars) positions measured at 2.3 and 8.4 GHz with the Very Long Baseline Interferometry (VLBI) technique. Most extragalactic radio sources exhibit spatially extended structures on milliarcsecond and sub-milliarcsecond scales which are variable in both time and frequency....
Dr
Minghui XU
(Shanghai Astronomical Observatory)
17/03/2016, 11:30
5: Geodetic and Astrometric VLBI Results
Oral Presentation
The CONT14 campaign features state-of-art VLBI data. Therein, the radio source 0642+449 was observed with about one thousand observables each day during the continuous observing period of fifteen days, providing tens of thousands of closure delays, the sum of the delays around a closed loop of baselines. The closure delay is independent of the instrumental and propagation delays and provides...
Dr
Bo Zhang
(Shanghai Astronomical Observatory)
17/03/2016, 11:45
5: Geodetic and Astrometric VLBI Results
Oral Presentation
The BeSSeL Survey (Bar and Spiral Structure Legacy Survey) is a VLBA Key Science project. The primary goal of the survey is to study the spiral structure and kinematics of the Milky Way, by measuring distances and proper motions to masers in regions of massive star formation across large portions of the Milky Way. To measure the distances of masers via trigonometric parallaxes, the relative...
Mr
Shuangjing Xu
(Shanghai Astronomical Observatory)
17/03/2016, 12:00
5: Geodetic and Astrometric VLBI Results
Oral Presentation
During the Chinese Lunar Mission hundreds of VLBI observations have been carried, we re-analysis all the quasar observations which used to calibrate the satellite observables. In each observation there are two quasar scans lasting about one hour, we use these data by splitting them into different time intervals and doing self-calibration each other in phase-referencing style to investigate the...
Mr
Sebastian Halsig
(Institute of Geodesy and Geoinformation, University of Bonn)
17/03/2016, 12:15
5: Geodetic and Astrometric VLBI Results
Oral Presentation
On its way through the atmosphere, the signals of space-geodetic techniques, such as GNSS or VLBI, are delayed and affected by bending and attenuation effects relative to a theoretical path in vacuum. Changing atmospheric conditions contribute considerably to the error budget of the observations. At the same time, space-geodetic techniques play a crucial role in the understanding of the...
Mr
Kyriakos Balidakis
(Technische Universität Berlin, Institute of Geodesy and Geoinformation Science, Berlin, Germany)
17/03/2016, 12:30
5: Geodetic and Astrometric VLBI Results
Oral Presentation
Due to the highly volatile character of the neutral atmosphere, the modeling of the related propagation delay is challenging. This poses the most prominent limitation in the precision and accuracy of the parameters estimated in very long baseline interferometry (VLBI) data analysis. Hence, it is of paramount importance that all parameters involved in the process to describe the atmosphere...
Dr
John Gipson
(NVI Inc/GSFC NASA)
17/03/2016, 14:15
5: Geodetic and Astrometric VLBI Results
Oral Presentation
Short term (daily to annual) variations in LOD are highly correlated with Atmospheric Angular Momentum. It has been known since the late 1980s and early 1990s that you could detect the effect of El Nino in the Length of Day (LOD). I review these results, paying particular attention to the current El Nino which is still developing, and is one of the strongest ever recorded. I look at...
Rüdiger Haas
(Chalmers University of Technology)
17/03/2016, 14:30
5: Geodetic and Astrometric VLBI Results
Oral Presentation
In 2007 the Geospatial Information Authority of Japan (GSI) and the Onsala Space Observatory (OSO) started a collaboration project aiming at determining the earth rotation angle, usually expressed as UT1-UTC, in near real-time. In the beginning of this project dedicated one hour long one-baseline experiments were observed periodically using the VLBI stations Onsala (Sweden) and Tsukuba...
Dr
Robert Heinkelmann
(GFZ Potsdam)
17/03/2016, 14:45
5: Geodetic and Astrometric VLBI Results
Oral Presentation
The Earth Orientation Parameters (EOP) are arguments of the time-dependent rotation matrices describing the difference in orientation between the Earth crust-fixed reference system, ITRS, and the space-fixed reference system, ICRS. Very Long Baseline Interferometry (VLBI) is the technique that connects the realizations of ITRS and ICRS in terms of orientation directly on the observation level....
Mrs
Anastasiia Girdiuk
(TU Wien)
17/03/2016, 15:00
5: Geodetic and Astrometric VLBI Results
Oral Presentation
This presentation is dedicated to the influence of diurnal atmosphere-ocean dynamics on Earth rotation and loading effects as observed by Very Long Baseline Interferometry. The first part focuses on the rotational signals associated with atmospheric tides, comprising small but non-negligible oscillations in the order 5 Μas. Here, we compare tidally analysed VLBI observations against...
