Dr
Graham Appleby
(NERC Space Geodesy Facility, Herstmonceux, UK)
14/03/2016, 09:15
1: Advances in VGOS Stations and Technology
Oral Presentation
Satellite Laser Ranging (SLR) is used to measure accurately the distance from ground stations to retro-reflectors on satellites and on the Moon. SLR is one of the fundamental space geodetic techniques that define the International Terrestrial Reference Frame (ITRF), which is the basis upon which many aspects of global change over space, time, and evolving technology are measured; with VLBI the...
Dr
Mamoru Sekido
(National Institute of Information and Communications Technology)
14/03/2016, 09:40
1: Advances in VGOS Stations and Technology
Oral Presentation
We are developing a new broadband VLBI system, named GALA-V with aim of frequency comparison between atomic time standards over intercontinental distances. The development of broadband GALA-V system is coordinated to be as compatible as possible with the VGOS system. Kashima 34m antenna that had modified Cassegrain optics was enabled to carry out broadband observation with originally developed...
Axel Nothnagel
(Institute of Geodesy and Geoinformation, University of Bonn)
14/03/2016, 10:05
1: Advances in VGOS Stations and Technology
Oral Presentation
On October 7 and 8, 2015, the IVS Directing Board held an IVS Retreat at the Dominion Radio Astrophysical Observatory, Penticton, BC, Canada, to discuss current implications and future challenges of the IVS’s existence and operations. In order to benefit from outside views, six external advisors had been invited as well. The group spent two days discussing correlation, product lines,...
Dr
Gino Tuccari
(INAF-IRA and MPI)
14/03/2016, 10:20
1: Advances in VGOS Stations and Technology
Oral Presentation
Multi-band concurrent observation capability for the frequencies bands commonly
used in EVN greatly could improve the VLBI scientific opportunities, even enabling important simplification in the radiotelescope operations.
The project for a 1.5 - 15.5 GHz fully digital receiver is presented with the
possible solutions for a smooth introduction in the different from each other
EVN radiotelescopes.
Dr
richard Biancale
(CNES/GRGS)
14/03/2016, 10:35
1: Advances in VGOS Stations and Technology
Oral Presentation
It is known that the VLBI Global Observing System (VGOS) network suffers from a lack of implementation in the South Pacific area. It is why GRGS was considering setting up a VLBI antenna in Tahiti in cooperation with NASA.
There is an existing geodetic observatory (OGT) in the campus of the French Polynesian University (UPF) which was created in 1998 in a tripartite cooperation between UPF,...
Mr
Leif Morten Tangen
(Norwegian Mapping Authority)
14/03/2016, 11:15
1: Advances in VGOS Stations and Technology
Oral Presentation
The existing 20 m telescope in Ny-Ålesund was set in operation in 1994. The telescope is more than 20 years now and is ready for retirement.
We decided to build a VGOS core site with twin telescopes. The existing telescope is just 70 meters away from the runway and the CAA did not allow us to build anything more so close.
The new site is about 1500 meters northwest of the old telescope and...
Dr
Guangli Wang
(Shanghai Astronomical Observatory)
14/03/2016, 11:30
1: Advances in VGOS Stations and Technology
Oral Presentation
The Seshan VGOS station is now in building. It is a very-fast-slewing 13.2m antenna, with QRFH wideband feed, and a realtime 3D measurement system of reference point variation is planing to install. And it locates in the yard of Tianma 65m radio telescope. Its recent progress will be introduced in this report.
Dr
Arthur Niell
(MIT Haystack Observatory)
14/03/2016, 11:45
1: Advances in VGOS Stations and Technology
Oral Presentation
The GGAO 12m and Westford 18m antennas are instrumented with the broadband signal chain to provide VGOS capability. These antennas have been making VGOS geodetic observations for more than a year. Approximately seventeen one- to twenty-four-hour VGOS sessions were conducted in 2015 to develop and test many of the procedures needed for an operational program, including scheduling, unattended...
Dr
Chet Ruszczyk
(MIT Haystack Observatory)
14/03/2016, 12:00
1: Advances in VGOS Stations and Technology
Oral Presentation
The Kokee Park Geophysical Observatory's 12m is expected to see First
Light early 2016. A description of the integration and testing that
was performed at MIT Haystack Observatory before shipping
the signal chain is described. This is followed by a summary of the
teams work that had to occur before first light and the initial
results.
Beyond KPGO first light focuses on the...
Mr
Ganesan Rajagopalan
(MIT Haystack Observatory)
14/03/2016, 12:15
1: Advances in VGOS Stations and Technology
Oral Presentation
MIT Haystack Observatory, as part of the NASA Space Geodesy Program, is delivering the first VGOS-compliant Signal Chain to the Kokee Park Geophysical Observatory (KPGO), Hawaii, and will soon be integrating and commissioning the KPGO 12-m station.
We will describe the Signal Chain subsystems and highlight the design and performance of the cryogenically cooled frontend. This incorporates a...
Gerhard Kronschnabl
(Geodetic Observatory Wettzell)
14/03/2016, 12:30
1: Advances in VGOS Stations and Technology
Oral Presentation
The VGOS antenna Ws at Wettzell is equipped with an Elevenfeed, having a continuous frequency range from 2 GHz - 14 GHz. The receiving system with eight parallel intermediate frequency channels enables the use of four bands at different polarizations. A DBBC in combination with a FILA10G and a Mark6 System is used as backend. The presentation gives an overview about the current status of the...
Mr
Evgeny Nosov
(IAA RAS)
14/03/2016, 14:00
1: Advances in VGOS Stations and Technology
Oral Presentation
Broadband Acquisition System (BRAS) was designed to digitize wideband signals from receivers of radio telescopes, pack the digital samples into VDIF frames and transmit them through 10G Ethernet interface. The system has been installed in Badary and Zelenchukskaya observatories on the recently constructed 13-meters RT-13 radio telescopes in February–March 2015. Since November 2016, IAA RAS...
Dr
Tomoaki Oyama
(NAOJ)
14/03/2016, 14:15
1: Advances in VGOS Stations and Technology
Oral Presentation
The new VLBI observing system (OCTAVE-DAS) have been developed based on the VSI-H and VDIF specifications at NAOJ (National Astronomical Observatory of Japan). It consists of 1) a high speed 1-20 Gsps 3-10 bit RF direct ADC (OCTAD) enable us to acquire not only wide intermediate frequency but also radio frequency up to 50 GHz and have DBBC functions for VGOS (VLBI Global Observing System), 2)...
Mr
harro verkouter
(Joint Institute for VLBI ERIC, Dwingeloo)
14/03/2016, 14:30
1: Advances in VGOS Stations and Technology
Oral Presentation
Modern, VGOS and general purpose radio-astronomical digital back ends (DBEs), will produce enormous amounts of data, posing some challenges for the recorders. Fortunately, the availability of ever faster digital hardware has also meant that capturing these large data streams on - relatively speaking - general purpose hardware has become quite feasible.
Currently there are two models of...
Dr
Roger Cappallo
(MIT Haystack Observatory)
14/03/2016, 14:45
2: VGOS Strategies and Expected Results
Oral Presentation
Now that significant amounts of data have begun to flow through the VGOS pipeline, we are encountering real-world issues in the fringe-fitting process. In order to create a high-quality geodetic observable one wants to minimize the sensitivity of group delay to instrumental parameters that may change over time, while at the same time maximizing the amount of information that is extracted. This...
Mr
Per Erik Opseth
(Norwegian Mapping Authority)
14/03/2016, 15:10
2: VGOS Strategies and Expected Results
Oral Presentation
February 26th 2015 the United Nations General assembly adopted the resolution on the Global Geodetic Reference Frame (GGRF). Presently major effort under a UN mandate is entered into developing a road map giving guidance to how the GGRF shall become sustainable. This work will influence the geodetic framework conditions in the years to come. As a contribution to global geodesy, Norway is...
Sten Bergstrand
(SP Technical Research Institute of Sweden)
14/03/2016, 15:45
We have used GPS-based local-tie measurements simultaneously with geo VLBI observations since 2008 during every geodetic VLBI session at Metsähovi. This system uses gimbal-mounted GNSS-antennas that are mounted on the reflector of the Metsähovi 14 m radio telescope. A similar system has been installed in 2013 at the Onsala 20 m radio telescope and been used for a large number of VLBI sessions,...
Mr
Ryoji Kawabata
(Geospatial Information Authority of Japan)
14/03/2016, 15:45
The Geospatial Information Authority of Japan (GSI) is constructing a new VGOS station in Ishioka. The construction of the 13-m antenna has been finished, and a new operation building will be completed by February 2016. Ishioka 13-m antenna is observing legacy S/X-band VLBI observation with Tsukuba 32-m antenna by using tri-band feed system. We have also carried out some broadband experiments...
Dr
David Gordon
(NVI, Inc./GSFC)
14/03/2016, 15:45
Difxcalc is a version of calc11 modified specifically for the
DiFX correlator. It is a replacement for the calc9.1
'calcserver' currently in use. To create difxcalc, all
of the Mark3 database handler calls were removed from calc11
and new input, output and initialization modules were
written and the flow of the program was modified
for correlator usage. Difxcalc takes as its
input the...
Yidan Huang
(Shanghai Astronomical Observatory)
14/03/2016, 15:45
The beacon of CE-3 satellite have several tones for communication and VLBI tracking. In order to improve data transferring and processing efficiency, we tried the local-correlation method which was different from the one used in CE-3 project. The Time delay model used in local-correlation experiment also differed from normal time delay model. The result shows that there are a few dozen meters...
Dr
Pablo de Vicente
(Observatorio de Yebes (IGN))
14/03/2016, 15:45
A series of joint test observations using three 13-m VGOS antennas were carried on between September and November, 2015. These were include 256 Mbps experiments as well as first 2 Gbps observations. Different working setups of DBBC were tested at Yebes, data recorded, and transferred to IAA Correlator Center. Combined correlation of mixed bandwidth data from KVAZAR antennas and Yebes were...
Dr
Alexander Neidhardt
(Technische Universität München, Geodätisches Observatorium Wettzell)
14/03/2016, 15:45
A new release of the telescope control software e-RemoteCtrl, which is designed to run VLBI observations remotely, has been extended with new monitoring capabilities.
The software extension is a test for further monitoring and control infrastructures for complete VLBI networks. The poster shows Ideas and already implemented elements.
Dr
Alexander Neidhardt
(Technische Universität München, Geodätisches Observatorium Wettzell)
, Dr
Pablo de Vicente
(Observatorio de Yebes (IGN))
14/03/2016, 15:45
The organization of first fast slewing observations with new VGOS antennas was decided during the VTC meeting at Ponta Delgada. The goal was to observe S/X-schedules regularly, using the fast slewing capabilities of the antennas as long as they are equipped with classic S/X-capabilities. The poster/presentation discusses and shows first results of these observations.
Mrs
Cynthia Thomas
(NVI, Inc.)
14/03/2016, 15:45
Continuous VLBI Campaigns (CONT) started in 1994 with the goal of demonstrating state of the art VLBI over a continuous period of time. The first CONT was followed by campaigns in 1995 and 1996. After a six year hiatus, CONT campaigns were organized approximately every three years from 2002 through 2014. In this presentation we primarily focus on the cornerstones of each CONT campaign....
Ms
Jiangying Gan
(Shanghai Astronomical Observatory,CAS)
14/03/2016, 15:45
VLBI(Very Long Baseline Interferometry) is an important radio astronomy
technology, is widely used in deep-space probers high-precision measurement. The correlator as the core data pre-processing equipment of VLBI, its performance is very important. At present, China VLBI data acquisition system (CDAS) can collect
data 2Gbps, and multiband combination can reach 16Gbps or 32Gbps. For ensure...
Brian Corey
(MIT Haystack Observatory)
, Dr
Vincenza TORNATORE
(Politecnico di Milano - DICA)
14/03/2016, 15:45
A number of new VGOS-radio telescopes are built or under construction, partly at new locations. VGOS radio telescopes enable observations in the range of 2-14 GHz. For this reason VGOS radio telescopes are much more receptive for unwanted radio frequency interference. RFI originates from local transmitting devices as well as from space based transmitting systems. Some space-borne devices may...
Dr
Nataliya Zubko
(Finnish Geospatial Research Institute)
14/03/2016, 15:45
The Metsähovi Geodetic Fundamental Station is a key infrastructure of the Finnish Geospatial Research Institute (FGI). It is a Global Geodetic Observing System (GGOS) core site, i.e., member of global network of geodetic stations which is used in maintaining global terrestrial and celestial reference frames, computing precise orbits of satellites, and for geophysical studies. Metsähovi is one...
Dr
Bill Petrachenko
(Natural Resources Canada)
14/03/2016, 15:45
The VLBI Global Observing System (VGOS) has been designed to take advantage of advances in data bandwidths, allowing for smaller and faster antennas, wider bandwidths, and shorter observation durations. Here, schedules for a "realistic" VGOS network, frequency sequences, and expanded source lists are presented using a new source-based scheduling algorithm. VGOS aims for continuous observations...
Johannes Boehm
(Technische Universität Wien)
14/03/2016, 15:45
The VLBI group at Technische Universität Wien (TU Wien) is going to run a VLBI software correlator for scientific purposes. For that reason, DiFX is installed on the Vienna Scientific Cluster 3 (VSC-3) consisting of 2020 nodes, each equipped with 2 processors (Intel Xeon E5-2650v2, 2.6 GHz, 8 cores). Of course, only a fraction of the total number of cores will be available for VLBI...
Prof.
Ludwig Combrinck
(HartRAO)
14/03/2016, 15:45
Very long baseline interferometry (VLBI) is used in geodesy to determine a telescope’s position relative to the galactic centre. A modern, fast slewing radio telescope measuring approximately 13 metres in diameter have been chosen to be used in the VLBI Global Observing System (VGOS), which will help improve the accuracy across global baselines from around 1 cm down to 1 mm. In 2014 HartRAO...
zhijun xu
(Shanghai Astronomical Observatory, CAS)
14/03/2016, 15:45
The hardware correlator have been used in Chinese Chang'E missions. Recently, a hardware correlator based on uniboard has been developed. This article presents the development of hardware correlator at SHAO and some results.
Mr
Christian Plötz
(Bundesamt für Kartographie und Geodäsie)
14/03/2016, 15:45
The German Antarctic Receiving Station (GARS) O’Higgins started in the early 1990th with regular VLBI operations. Because of its remote position on the Antarctic Peninsula, the VLBI observation was mostly restricted to the Antarctic summer month. New equipment, a continuous operation by the German Aerospace Center (DLR), and new realizations of observation schedules may open the door for...
Dr
Kazuhiro Takefuji
(NICT)
, Dr
Mamoru Sekido
(National Institute of Information and Communications Technology)
14/03/2016, 15:45
The Kashima 34 m radio telescope, the cassegrain optics is currently realized 3.2GHz to 14 GHz receiver system by installing the NINJA feed. Furthermore a direct sampler GALAS easily connect four 1GHz bandwidth without any analogue frequency converter and phase-cal.
VGOS, EHT and other astronomy VLBI highly demand broadband system for better delay determination, shorter integration time and...
Dr
Halfdan Pascal Kierulf
(Norwegian Mapping Authority)
14/03/2016, 15:45
In February 2015 the UN General Assembly adopted the resolution “A Global Geodetic Reference Frame for Sustainable Development” - the first resolution recognizing the importance of a globally-coordinated approach to geodesy. The GGRF Working Group is working on the development of a roadmap that will describe how governments can contribute to the sustainability and enhancement of the Global...
Dr
Pablo de Vicente
(Observatorio de Yebes (IGN))
14/03/2016, 15:45
An update of the deployment and activities at the Spanish/Portuguese RAEGE project (“Atlantic Network of Geodynamical and Space Stations”) is presented. Regular observations with Yebes radio telescope are ongoing. Commissioning of the radio telescope at Santa Maria is advanced, and site works for a new station in Tenerife (Canary Islands) have started. Technological developments on receivers...
Dr
Guangli Wang
(Shanghai Astronomical Observatory)
14/03/2016, 17:00
On Sept. 20, 2015, the Chinese CZ-6 test rocket was launched successfully from TaiYuan Satellite Launch Center, and 20 satellites was sent simultaneously into a circular, near-polar and 520 Km altitude orbit. Among these 20 satellites, four CubSats, named with APOD (Atmospheric density detection and Precise Orbit Determination), are projected for atmospheric density in-situ detection and...
Johannes Boehm
(Technische Universität Wien)
14/03/2016, 17:00
BACC(Beijing Aerospace Control Center), as the command center for the Chinese space program, got access to VieVS in 2011. Since 2013, IVS VLBI data has been downloaded and analyzed automatically with VieVS at BACC and the geodetic products will be provided firstly in the presentation. VieVS was also used to estimate the coordinates of new Chinese VLBI telescopes with domestic VLBI network in...
Dr
Tobias Nilsson
(GFZ German Research Centre for Geosciences)
14/03/2016, 17:00
The VLBI Intensive sessions are one-hour long, usually single-baseline VLBI sessions performed every day in order to estimate UT1-UTC. Due to the small number of observations in these sessions, the latency between observation and results is relatively short, normally a few days. However, the accuracy of the UT1-UTC estimates is significantly lower than expected based on their formal errors....
Prof.
Ludwig Combrinck
(HartRAO)
14/03/2016, 17:00
Relativistic geodesy is typically seen as a new type of gravity potential measurement technique using very high accuracy clocks; these clocks are more stable (by a factor of 100 or 1000) than the hydrogen masers currently used at VLBI stations. In modern terms however, geodesy entails much more than just geodesy of the Earth, therefore the term relativistic geodesy is re-assessed. The possible...
Dr
Aletha de Witt
(Hartebeesthoek Radio Astronomy Observatory)
14/03/2016, 17:00
K-band (22 GHz) radio observations have the potential to form the basis for the most accurate celestial reference frame ever constructed. Relative to the standard S/X (2.3/8.4 GHz) observing bands, K-band is expected to exhibit a reduction in extended source morphology and core-shift. This reduction in astrophysical systematics should allow for a more stable celestial reference frame at K-band...
Dr
Fengchun Shu
(Shanghai Astronomical Observatory)
14/03/2016, 17:00
Using the same frequency standard, a high-precision phase delay can be obtained in a connected element interferometry (CEI) system. Beidou GEO navigation satellite C02 is tracked from a CEI observations, where the CEI of the two stations at hangtiancheng and shahe linked by a phase stabilization system is built by Beijing Aerospace Control Center (BACC). And Beidou GEO navigation satellite C03...
Prof.
Thomas Hobiger
(Chalmers / Onsala Space Observatory)
14/03/2016, 17:00
Onsala Space Observatory hosts two 2.3 m radio telescopes called SALSA ("Such a lovely small antenna") which are utilised to bring front-line interactive astronomy to the classroom. Until now SALSA has been used for astronomical educational purposes solely, in particular demonstrating the concept of single dish measurements. However, it is possible to combine both SALSAs to an interferometer...
Dr
John Gipson
(NVI Inc/GSFC NASA)
14/03/2016, 17:00
An on-going goal of the GSFC Analysis Center is the improvement of the UT1 formal error obtained from the IVS-INT01 sessions, as well as the improvement of related metrics, such as robustness against atmospheric turbulence. Improvement can be achieved by improving the scheduling and/or the analysis of these sessions. Here we report on our latest efforts to improve the performance of the...
Dr
Thomas Artz
(Institute of Geodesy and Geoinformation, University of Bonn)
14/03/2016, 17:00
Although several fully developed VLBI software packages exist already, the VLBI group of the Institute of Geodesy and Geoinformations of Bonn University (ivg) started implementing a new analysis toolbox. The main reason is the need for a flexible environment, which allows for straightforward implementations of new scientific and software-related ideas for VLBI data analysis. Furthermore, we...
Mr
Kyriakos Balidakis
(Technische Universität Berlin, Institute of Geodesy and Geoinformation Science, Berlin, Germany)
14/03/2016, 17:00
In this study, the issue of the quality of meteorological data employed for VLBI data analysis is addressed. Traditionally, ambient barometric pressure and temperature values are used to model the hydrostatic component of the neutral atmospheric propagation delay and the thermal deformation of antennas, in VLBI data analysis. Unlike the other microwave-based space geodetic techniques currently...
Axel Nothnagel
(Institute of Geodesy and Geoinformation, University of Bonn)
,
Rüdiger Haas
(Chalmers University of Technology)
14/03/2016, 17:00
The successful deployment of the Chang’E-3 Lander on the Moon on Dec 14th, 2013 has opened a new window for VLBI observations of the Moon. Following proposals to the IVS Observing Program Committee, a global IVS R&D network augmented with two China Deep Space Stations was configured for joint observations of the lander in a project called OCEL (Observing the Chang’E-3 Lander with VLBI). From...
Fengchun Shu
(Shanghai Astronomical Observatory)
14/03/2016, 17:00
The goal of VLBI Ecliptic Plane Survey (VEPS) is to increase the number of calibrator radio sources within 7.5 degree of the ecliptic plane by surveying a complete sample of sources with single dish flux densities at 5 GHz greater than 50 mJy. A dense grid of calibrators along ecliptic plane with very accurate coordinates is required for many applications, including observations of spacecrafts...
Mr
Gerald Engelhardt
(BKG (Federal Agency for Cartography and Geodesy))
14/03/2016, 17:00
The Tsukuba station in Japan is an essential station in the IVS Intensive series for rapid UT1 estimation. The use of this station in rapid UT1 estimation requires a set of best-predetermined station coordinates but the consequences of the Earthquake in Japan in March 2011 were such that the previously known velocity rates of the station Tsukuba were unusable.
Since 2012, the VLBI group at...
Dr
Shabala Stanislav
(University of Tasmania)
14/03/2016, 17:00
Radio sources observed in global IVS sessions are mostly flat-spectrum radio-loud quasars. While some quasars appear almost point like, many have extended jet components in addition to compact cores. The structure of these jets often varies on timescales of months to years as the black hole at the centre of the quasar accretes new material and ejects components of radio-emitting plasma. These...
Ms
Glenda Coetzer
(HartRAO)
14/03/2016, 17:00
The Hartebeesthoek Radio Astronomy Observatory (HartRAO) participates in astronomic, astrometric and geodetic Very Long Baseline Interferometry (VLBI) observations using both 26- and 15-m diameter radio telescopes. These as well as additional geodetic data from a Satellite Laser Ranger (SLR), Global Navigation Satellite System (GNSS), Met4 weather stations, a new seismic network must be stored...
Mr
César GATTANO
(SYRTE - Observatoire de Paris)
14/03/2016, 17:00
Very Long Baseline Interferometry is the only technique that can estimate Earth nutations with an accuracy under the milliarcsecond level. With 35 years of geodetic VLBI observations, the principal nutation terms caused by luni-solar tides and geophysical response have been estimated. We focuse on the variabity. Two of them present very significant amplitude and phase variations : the...
Dr
John Gipson
(NVI Inc/GSFC NASA)
14/03/2016, 17:00
The IVS Working Group 4 developed the new format to store and exchange data obtained from geodetic VLBI observations. The new data format, vgosDb, will replace existing Mk4 databases this year. At the GSFC NASA we developed software that will implement vgosDb format and will be used routinely to convert correlator output to the new data storage format. On this poster we present the vgosDb...
Dr
Alexander Neidhardt
(Technische Universität München, Geodätisches Observatorium Wettzell)
14/03/2016, 17:00
The ESA Venus and Mars Express spacecrafts were observed at X-band with the Wettzell radio telescopes Wn and Wz in a framework of the assessment study of the possible contribution of the European VLBI network to the upcoming ESA deep space missions and further projects. These observations were extended to regular weekly sessions to routinely run the processing and analysis pipeline. Recorded...
Johannes Boehm
(Technische Universität Wien)
14/03/2016, 17:00
The next realisation of the International Terrestrial Reference System, the ITRF2014, is currently in preparation or under evaluation, respectively. The VLBI input to ITRF2014 is provided by the International VLBI Service for Geodesy and Astrometry (IVS) and consists of a combination of all analysis center contributions. One of these single solutions is contributed by the Vienna special...
Johannes Böhm
(Technische Universität Wien)
14/03/2016, 17:00
The Vienna VLBI Software (VieVS) is a VLBI analysis software developed and maintained at Technische Universität Wien (TU Wien) since 2008 with contributions from groups all over the world. It is used for both academic purposes in university courses as well as for providing VLBI analysis results to the geodetic community. Written in a modular structure in Matlab, VieVS offers easy access to the...
Dr
Guangli Wang
(Shanghai Astronomical Observatory)
14/03/2016, 17:00
VLBI technique was used in China’s Lunar Exploration Project Since the Chang’E-1 launched in the year of 2007, after then VLBI was played an important role in the series of Chang’E missions, CE-2, CE-3 and CE-5T1, and will be continued in the future space mission. The observation network consists of Shanghai 25m&65m, Beijing 50m, Kunming 40m and Urumqi 25m radio telescopes. Up to now it still...
Mr
César GATTANO
(SYRTE - Observatoire de Paris)
14/03/2016, 17:00
Until now, the main criteria for selecting geodetic sources were based on astrometric stability and structure at 8 GHz [Fey et al., 2015]. Other physical characteristics, especially at other wave-lengths, including the optical, should also enter the selection procedure. To this aim, we propose to summarize all known physical caracteristics, thanks to the use of three different catalogs : the...
Dr
Dan MacMillan
(NVI, Inc./NASA GSFC)
15/03/2016, 09:00
2: VGOS Strategies and Expected Results
Oral Presentation
We simulated future networks of VLBI+SLR sites to assess their performance. The objective is to build a global network of geographically well distributed collocated next generation sites from each of the space geodetic techniques. The network is being designed to meet the GGOS terrestrial reference frame goals of 1 mm in accuracy and 0.1 mm/yr in stability. We simulated the next generation...
Dr
Bill Petrachenko
(Natural Resources Canada)
15/03/2016, 09:15
2: VGOS Strategies and Expected Results
Oral Presentation
Source structure has long been recognized as a significant risk factor for the broadband method. The issue of greatest concern is that structure related phases and delays will lead to cycle slips during broadband phase connection. These errors will be difficult to handle since they are both subtle to detect and almost certainly impossible to correct after the fact.
As the advent of VGOS...
Dr
Lucia Plank
(University of Tasmania)
15/03/2016, 09:30
2: VGOS Strategies and Expected Results
Oral Presentation
With the transition to VGOS, co-located radio telescopes will be common at many sites. This can be as a sibling telescope, when a VGOS antenna is built next to a legacy one or as the concept of a twin telescope, with two identical VGOS antennas.
The co-location of two antennas offers new possibilities in both operation and analysis. The immediate question for observing with a sibling/twin...
Dr
Jim Lovell
(University of Tasmania)
15/03/2016, 09:45
2: VGOS Strategies and Expected Results
Oral Presentation
The continuous observing mode envisioned for the new array of VGOS stations would benefit greatly from a high level of automation, from scheduling through to analysis. The centrally-operated AuScope VLBI array of three 12m antennas in Australia is serving as a testbed for these automation techniques. Here we describe the challenges we are addressing, how we are using simulations to undertand...
Dr
Alexander Neidhardt
(Technische Universität München, Geodätisches Observatorium Wettzell)
15/03/2016, 10:00
2: VGOS Strategies and Expected Results
Oral Presentation
A first test implementation of an auxiliary data archive is tested at the Geodetic Observatory Wetttzell. It is software which follows-on the Wettzell SysMon, extending the database and data sensors with the functionalities of a professional monitoring environment, named Zabbix. Some extensions to the remote control server on the NASA Field System PC enable the inclusion of data from external...
Prof.
Alexander Ipatov
(Institute of Applied Astronomy RAS)
15/03/2016, 10:15
2: VGOS Strategies and Expected Results
Oral Presentation
IAA finished work on creation of new generation radio interferometer with two VGOS antennas at the Badary and Zelenchukskaya co-location stations. The series of 48 one base 1 hour VLBI sessions (up to four sessions per day) were performed from 04 Nov to 18 Nov 2015. Observations were carried out using wideband S/X receivers, 3 X-band and 1 S-band 512 MHz channels at one or two circular...
Sten Bergstrand
(SP Technical Research Institute of Sweden)
15/03/2016, 11:00
3: Stations, Correlators, and Operations Centers
Oral Presentation
The combination of space geodetic solutions is critically reliant on the availability of local tie vectors, which are the relative positions of the reference points of co-located space geodetic
instruments determined by some survey technique. Tie vectors enter the combination of space geodetic solutions effectively as a fifth technique and are not only necessary for rigorous terrestrial...
Prof.
Torben Schüler
(Geodetic Observatory Wettzell - BKG)
15/03/2016, 11:25
3: Stations, Correlators, and Operations Centers
Oral Presentation
The Geodetic Observatory Wettzell features a 20 m radiotelescope (RTW) as well as two new 13.2 m TWIN telescopes. Whilst RTW performs routine operations since 1984, the first of the TWIN telescopes, TTW1, has entered its productive phase in mid 2014, and TTW2 has just been equipped with an Elevenfeed broadband receiving system.
The triple telescope array at Wettzell establishes a geodetic...
Mr
Sang Oh YI
(NGII(National Geographic Information Institutue))
15/03/2016, 11:40
3: Stations, Correlators, and Operations Centers
Oral Presentation
The Sejong station is a part of SGOC(Space Geodetic Observation Center) which belongs to NGII(National Geographic Information Institute). We will present conventional S/X system issues that we need to improve, establishment of sever cluster for S/W correlation(Storage about 100TB), local tying results for collocation, installation of the ARGO(Mobile SLR system, 40cm diameter) which developed...
Mr
Ryoji Kawabata
(Geospatial Information Authority of Japan)
15/03/2016, 11:55
3: Stations, Correlators, and Operations Centers
Oral Presentation
The Geospatial Information Authority of Japan (GSI) has been operating Network Stations such as Tsukuba 32-m antenna, Tsukuba Correlator, and Tsukuba Analysis Center. Recently we started to operate a new VGOS antenna, Ishioka 13-m antenna, which will take over the role of Tsukuba 32-m antenna and, on the other side, stopped operation of the three regional antennas in Japan. GSI is now being...
Dr
Takaaki Jike
(National Astronomical Observatory of Japan)
15/03/2016, 12:10
3: Stations, Correlators, and Operations Centers
Oral Presentation
According to increasing the number of observations by 1-Gbps recording, geodetic VLBI solutions of VERA improve the accuracy. This is for guaranteeing the accuracy of VERA astrometry. However, much more increase in the number of observations is already difficult by the limit of the driving performance of the VERA antenna. OCTAVE series is a candidate of a next-generation data processing system...
Dr
Aletha de Witt
(Hartebeesthoek Radio Astronomy Observatory)
15/03/2016, 12:25
3: Stations, Correlators, and Operations Centers
Oral Presentation
Currently SKA-SA and HartRAO are converting the redundant 34-m telecommunications antenna in Ghana to a radio telescope. The Ghanaian radio telescope will be the second element, HartRAO the first, of what will become the African VLBI Network (AVN). There are 29 documented 30-m class telecommunications antennas in 19 African countries (though some have been destroyed). It is proposed that...
Mr
Matteo Stagni
(IRA - INAF)
16/03/2016, 09:00
3: Stations, Correlators, and Operations Centers
Oral Presentation
A first 24-h Italian VLBI geodetic experiment, involving the Medicina, Noto and Matera antennas, shaped as an IVS standard EUROPE, was successfully performed. Starting from the correlator output, a geodetic database was created and a typical solution of a small network was achieved, here presented. From this promising result, we have planned new observations in 2016, involving the three...
Dr
Pablo de Vicente
(Observatorio de Yebes (IGN))
16/03/2016, 09:15
3: Stations, Correlators, and Operations Centers
Oral Presentation
As chair of the Technical and Operations Group (TOG) of the European VLBI Network (EVN) I would like to present an overview of the technical aspects of the EVN. I will explain which institutes and telescopes constitute the EVN, and their main characteristics and observation frequencies. The scheduling process together with fringe tests, network monitor experiments, standard observations,...
Arno Mueskens
(IGG Uni Bonn)
16/03/2016, 09:30
3: Stations, Correlators, and Operations Centers
Oral Presentation
We present the status of the Bonn Correlator Center (2015/2016)
for astronomical and geodetic correlation. The correlator
center is being operated jointly by the Max Planck Institute for Radio
Astronomy (MPIfR) in Bonn, the Federal Agency for
Cartography and Geodesy (BKG) in Frankfurt with support from the
Institute of Geodesy and Geoinformation (IGG) in Bonn for more than 20
years.
We...
Dr
Bob Campbell
(JIVE)
16/03/2016, 09:45
3: Stations, Correlators, and Operations Centers
Oral Presentation
Real-time e-VLBI continues to form an integral element of the European VLBI Network (EVN), accounting for about a quarter of all EVN hours and providing unique rapid-response capabilities to transient events as well as the opportunity for higher-cadence observations compared to the standard EVN sessions that fall three times per year. The EVN software correlator at JIVE (SFXC) can currently...
Dr
Wu Jiang
(SHAO,CAS)
16/03/2016, 10:00
3: Stations, Correlators, and Operations Centers
Oral Presentation
Shanghai Astronomical Observatory has upgraded its DiFX cluster to a 420 cpu cores and a 432 TB storage system at the end of 2014. An international network connection for the raw data transfer has also been established. The routine operations for IVS sessions including CRF, AOV, and APSG series began from the ealy 2015.Some X/Ka fringe search experiments were conducted with Tianma 65-m radio...
Mr
renjie zhu
(Shanghai Astronomical Observatory, Chinese Academy of Science)
16/03/2016, 10:15
3: Stations, Correlators, and Operations Centers
Oral Presentation
Abstract: Shanghai Astronomical Observatory(SHAO) has started to development VLBI digital backend in 2004. And since 2010, the first generation of digital backends named CDAS(Chinese VLBI Data Acquisition System) have been installed in CVN VLBI stations and applied in several projects. This presentation will introduce the history, the current status and the future of the VLBI digital backends...
Mr
Matteo Stagni
(IRA - INAF)
16/03/2016, 10:30
3: Stations, Correlators, and Operations Centers
Oral Presentation
We present the first field-test of the implementation of a coherent optical fiber link for remote antenna synchronization realized in Italy between the Italian Metrological Institute (INRIM) and the Medicina radio observatory. The Medicina VLBI antenna participated to the Eur137 experiment carried out in September 2015, in tag along mode, using, as reference systems, both the local H maser...
Dr
Thomas Artz
(Institute of Geodesy and Geoinformation, University of Bonn)
16/03/2016, 11:10
4: Data Structures and Analysis Strategies in the VGOS Era
Oral Presentation
In a traditional least squares adjustment of parameters to the VLBI observation, typically tropospheric as well as clock parameters are determined in form of continuous piece-wise linear functions (CPWLF) with a given temporal resolution. As the VLBI observations are not equidistant, and on the contrary, exhibit gaps of sometimes several hours, singularities arise due to unresolvable...
Mr
Niko Kareinen
(Chalmers University of Technology)
16/03/2016, 11:25
4: Data Structures and Analysis Strategies in the VGOS Era
Oral Presentation
Robust and automatic estimation of ambiguities is one of the main requirements for a fully automated analysis of Intensive sessions. We apply the L1-norm minimization to ambiguity estimation and ionosphere calibration using the c5++ analysis software. This study includes IVS Intensive sessions on the Kokee-Wettzell baseline from 2001 to 2015 where Version-1 database are accessible. Version-1...
Mr
Grzegorz Klopotek
(Chalmers University of Technology)
16/03/2016, 11:40
4: Data Structures and Analysis Strategies in the VGOS Era
Oral Presentation
The IERS Conventions contain recommendations, definitions and models for space geodetic techniques including geodetic VLBI. In practice, different analysis software packages follow different estimation methods, use a variety of different correction models and sometimes adhere to conventions that might not be the latest. This may lead to differences in the results that should not appear among...
Dr
Tobias Nilsson
(GFZ German Research Centre for Geosciences)
16/03/2016, 11:55
4: Data Structures and Analysis Strategies in the VGOS Era
Oral Presentation
The VLBI Global Observing System (VGOS) will present a number of challenges for VLBI data analysis. For example, there will be an increase in the number of observations per day by a factor of 10-30 or even more. Furthermore, another goal of VGOS is to reduce the latency between observation and availability of the results, like the Earth Orientation Parameters (EOP) to less than one day....
Ms
Ann-Silje Kirkvik
(Norwegian Mapping Authority)
16/03/2016, 12:10
4: Data Structures and Analysis Strategies in the VGOS Era
Oral Presentation
The Norwegian Mapping Authority has been using GEOSAT to analyze 24-hour VLBI sessions. GEOSAT was originally developed by Per Helge Andersen at the Norwegian Research Defense Establishment, but is now owned by Norwegian Mapping Authority. GEOSAT is a multi-technique geodetic analysis software that aims to process observations from VLBI, SLR, GNSS and DORIS to improve the global geodetic...
Dr
Richard Gross
(Jet Propulsion Laboratory)
16/03/2016, 14:00
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
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
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
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
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
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...
Prof.
Harald Schuh
(GFZ German Research Center for Geosciences)
16/03/2016, 16:50
Through the analysis of geodetic VLBI data a multitude of scientific topics in geodesy, geophysics, and astronomy can be covered. Starting from astrometry, relativity, and the essential contribution of VLBI to the terrestrial reference frames, geophysical effects like loading and deformation of the Earth’s crust, variations of the Earth orientation parameters, and changes of the troposphere...
Mr
David Mayer
(Technische Universität Wien)
17/03/2016, 09:00
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
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
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
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
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
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...
Mr
Sayan Basu
(University of South Africa and Hartebeesthoek Radio Astronomy Observatory, South Africa)
17/03/2016, 11:15
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
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
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
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
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
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
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
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
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
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...
Prof.
Markus Rothacher
(ETH Zurich)
17/03/2016, 15:15
In recent years much effort has been undertaken to combine space geodetic observations on-board satellites, known as co-location in space. Whereas for SLR and GNSS, co-locations on-board satellites already exist (LEO, GNSS), no such satellites are allowing at present for VLBI observations. In order to cure this situation new satellite missions like GRASP are considered, new observation...
Mr
Andreas Hellerschmied
(Technische Universität Wien)
17/03/2016, 16:15
The observation of GNSS satellites with the geodetic VLBI system is an interesting approach which offers a variety of new possibilities. Promising applications can be found, among others, in the field of inter technique ties. Such observations provide possibilities to directly connect the dynamic GNSS and the kinematic VLBI reference frame, which may result in improved future ITRF...
Mr
Weimin Zheng
(Shanghai Astronomical Observatory,CAS)
17/03/2016, 16:30
VLBI is a radio astronomy tool with very high space angle resolution and Chinese VLBI Network has played a important roles in the Chang’E series lunar mission. In the upcoming Chinese lunar and deep space missions, higher angular position ability is needed. For these reasons, we carried out research on accurate spacecraft positioning and conducted several space vehicles phase-referencing...
Axel Nothnagel
(Institute of Geodesy and Geoinformation, University of Bonn)
17/03/2016, 16:45
Oral Presentation
