BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:About the extension of the coordinate parametrization of radio sou rces in VLBI DTSTART;VALUE=DATE-TIME:20160317T083000Z DTEND;VALUE=DATE-TIME:20160317T084500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4568@events.saip.org.za DESCRIPTION:Speakers: Maria Karbon (GFZ)\nUsually celestial radio sources in the celestial reference frame (CRF) catalog are divided in three catego ries: defining\, special handling\, and others. The defining sources are t hose used for the datum realization of the celestial reference frame\, i.e . they are included in the No-Net-Rotation (NNR) constraints to maintain t he axis orientation of the CRF\, and are modeled with one set of totally c onstant coordinates. At the current level of precision\, the choice of the defining sources has a significant effect on the coordinates. For the ICR F2 295 sources were chosen as defining sources\, based on their geometrica l distribution\, statistical properties\, and stability. The number of def ining sources is a compromise between the reliability of the datum\, which increases with the number of sources\, and the noise which is introduced by each source. Thus\, the optimal number of defining sources is a trade-o ff between reliability\, geometry\, and precision.\n\nIn the ICRF2 only 39 of sources were sorted into the special handling group as they show large fluctuations in their position\, therefore they are excluded from the NNR conditions and their positions are normally estimated for each VLBI sessi on instead of as global parameters. All the remaining sources are classifi ed as others. However\, a large fraction of these unstable sources show ot her favorable characteristics\, e.g. large flux density (brightness) and a long history of observations. Thus\, it would prove advantageous includin g these sources into the NNR condition. However\, the instability of these objects inhibit this. If the coordinate model of these sources would be e xtended\, it would be possible to use these sources for the NNR condition as well. All other sources are placed in the “others” group. This is t he largest group of sources\, containing those which have not shown any ve ry problematic behavior\, but still do not fulfill the requirements for de fining sources.\n\nStudies show that the behavior of the sources can vary dramatically in time. Hence\, each source should be modeled individually. Considering this\, the shear amount of sources\, in our study more than 90 0 are included\, sets practical limitations.\n\nWe decided to use the mult ivariate adaptive regression splines (MARS) procedure to parametrize the s ource coordinates\, as they allow a great deal of automation as it combin es recursive partitioning and spline fitting in an optimal way. The algori thm finds the ideal knot positions for the splines and thus the best numbe r of polynomial pieces to fit the data. We investigate linear and cubic sp lines determined by MARS to "human" determined linear splines and their im pact on the CRF.\n\nWithin this work we try to answer the following questi ons: Do we still need the categorizations in stable\, special handling and other sources? If yes\, how can we find optimal criteria for the definiti on of these categories? Whats the best approach to find the best fitting p olynomials? And finally\, what can we gain by introducing this type of par ametrization within the CRF determination?\n\nhttps://events.saip.org.za/e vent/56/contributions/4568/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4568/ END:VEVENT BEGIN:VEVENT SUMMARY:Aspects of ICRF-3 DTSTART;VALUE=DATE-TIME:20160316T132500Z DTEND;VALUE=DATE-TIME:20160316T134000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4569@events.saip.org.za DESCRIPTION:Speakers: Chopo Ma (NASA Goddard Space Flight Center)\nThe Sec ond Realization of the International Celestial Reference Frame (ICRF) used dual-frequency VLBI data acquired for geodetic and astrometric purposes f rom 1979-2009 by organizations coordinated by the IVS and various precurso r networks. Since 2009 the data set has been significantly broadened\, es pecially by observations in the Southern Hemisphere\, and modeling of astr onomical\, geophysical and tropospheric effects has progressed. While the new southern data have ameliorated the north/south imbalance of observati ons\, they appear to cause a systematic zonal declination change in the ca talog positions. Over the three decades of the ICRF data set the effect o f galactic aberration may be significant. Geophysical and tropospheric mo dels also may affect the source positions. All these effects need to be a ddressed in preparation for ICRF-3.\n\nhttps://events.saip.org.za/event/56 /contributions/4569/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4569/ END:VEVENT BEGIN:VEVENT SUMMARY:Report on the current activities of GSI VLBI DTSTART;VALUE=DATE-TIME:20160315T095500Z DTEND;VALUE=DATE-TIME:20160315T101000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4570@events.saip.org.za DESCRIPTION:Speakers: Ryoji Kawabata (Geospatial Information Authority of Japan)\nThe Geospatial Information Authority of Japan (GSI) has been opera ting Network Stations such as Tsukuba 32-m antenna\, Tsukuba Correlator\, and Tsukuba Analysis Center. Recently we started to operate a new VGOS ant enna\, 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 regiona l antennas in Japan. GSI is now being actively involved in the Asia-Oceani a VLBI Group for Geodesy and Astrometry (AOV) by using Tsukuba 32-m and Is hioka 13-m antenna and by correlating regular AOV sessions. We will talk o n the current activities of GSI VLBI.\n\nhttps://events.saip.org.za/event/ 56/contributions/4570/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4570/ END:VEVENT BEGIN:VEVENT SUMMARY:DINNER TALK: Half a century of geodetic VLBI analysis – a personal retrospect and future outlook DTSTART;VALUE=DATE-TIME:20160316T145000Z DTEND;VALUE=DATE-TIME:20160316T151500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4571@events.saip.org.za DESCRIPTION:Speakers: Harald Schuh (GFZ German Research Center for Geoscie nces)\nThrough the analysis of geodetic VLBI data a multitude of scientifi c topics in geodesy\, geophysics\, and astronomy can be covered. Starting from astrometry\, relativity\, and the essential contribution of VLBI to t he terrestrial reference frames\, geophysical effects like loading and def ormation of the Earth’s crust\, variations of the Earth orientation para meters\, and changes of the troposphere and ionosphere can be investigated . Examples of some results achieved in the last decades will be given\, an d a future outlook of VLBI analysis will be provided.\n\nhttps://events.sa ip.org.za/event/56/contributions/4571/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4571/ END:VEVENT BEGIN:VEVENT SUMMARY:The UN-GGIM Roadmap for the Global Geodetic Reference Frame DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4572@events.saip.org.za DESCRIPTION:Speakers: Halfdan Pascal Kierulf (Norwegian Mapping Authority) \nIn February 2015 the UN General Assembly adopted the resolution “A Glo bal Geodetic Reference Frame for Sustainable Development” - the first re solution 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 a nd enhancement of the Global Geodetic Reference Frame. The ambition is tha t UN-GGIM 6th session endorses the GGRF Roadmap in New York in August 2016 .\n\nWe will address the ongoing work with the roadmap and future plans. W e will also discuss the opportunities and benefits of the UN resolution an d roadmap for the development of geodesy and geodetic networks like VGOS.\ n\nhttps://events.saip.org.za/event/56/contributions/4572/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4572/ END:VEVENT BEGIN:VEVENT SUMMARY:Building a new core station in Ny-Ålesund DTSTART;VALUE=DATE-TIME:20160314T091500Z DTEND;VALUE=DATE-TIME:20160314T093000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4573@events.saip.org.za DESCRIPTION:Speakers: Leif Morten Tangen (Norwegian Mapping Authority)\nTh e 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. \nWe dec ided to build a VGOS core site with twin telescopes. The existing telescop e is just 70 meters away from the runway and the CAA did not allow us to b uild anything more so close. \nThe new site is about 1500 meters northwest of the old telescope and we had to build a road with a bridge. This was f inished summer 2014 and the construction work started in October 2014. It is a bit challenging to do construction work during wintertime at 79 degre e north with permafrost. During the winter\, the VLBI fundaments came up. Station\, SLR and gravity buildings are built too. \nThis presentation wil l show what is done until now and different solutions for the telescopes. The telescopes shall arrive\, April 2016\n\nhttps://events.saip.org.za/eve nt/56/contributions/4573/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4573/ END:VEVENT BEGIN:VEVENT SUMMARY:Next Generation Global Geodetic Networks for GGOS DTSTART;VALUE=DATE-TIME:20160315T070000Z DTEND;VALUE=DATE-TIME:20160315T071500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4574@events.saip.org.za DESCRIPTION:Speakers: Dan MacMillan (NVI\, Inc./NASA GSFC)\nWe simulated f uture networks of VLBI+SLR sites to assess their performance. The objectiv e is to build a global network of geographically well distributed collocat ed next generation sites from each of the space geodetic techniques. The n etwork is being designed to meet the GGOS terrestrial reference frame goal s of 1 mm in accuracy and 0.1 mm/yr in stability. We simulated the next ge neration networks that should be available in 5 years and in 10 years to a ssess the likelihood that these networks will meet the reference frame goa ls. Simulations were based on the expectation that 17 broadband VLBI stati ons will be available in 5 years and 27 stations in 10 years. We also con sider the improvement resulting from expanding the network by 6 additional VLBI sites to improve the global distribution of the network. In the sim ulations\, the networks will operate continuously\, but we account for sta tion downtime for maintenance or because of bad weather. We assess the agr eement between the estimated SLR and VLBI coordinate differences and the s urvey ties by doing combination TRF solutions that tie the networks togeth er only through the estimation of EOP. The strengths of VLBI and SLR allo ws them to provide the necessary reference frame accuracy in scale\, geoce nter\, and orientation. Even with just the +5 year network operating for 10 years\, simulations indicate that accuracies will be at the level of 0. 03 ppb\, 0.3mm\, and 10 µas. Combining the +5 year and +10 network realiz ation will provide better estimates of accuracy.\n\nhttps://events.saip.or g.za/event/56/contributions/4574/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4574/ END:VEVENT BEGIN:VEVENT SUMMARY:VERA K-band Geodetic VLBI experiment using newly developed high sp eed sampler and recorder DTSTART;VALUE=DATE-TIME:20160315T101000Z DTEND;VALUE=DATE-TIME:20160315T102500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4575@events.saip.org.za DESCRIPTION:Speakers: Takaaki Jike (National Astronomical Observatory of J apan)\nAccording to increasing the number of observations by 1-Gbps record ing\, geodetic VLBI solutions of VERA improve the accuracy. This is for gu aranteeing the accuracy of VERA astrometry. However\, much more increase i n the number of observations is already difficult by the limit of the driv ing performance of the VERA antenna. OCTAVE series is a candidate of a nex t-generation data processing system in VERA. Sampling/recording rate of th e system is 8-Gbps and corresponds by 8 times the present recording rate o f VERA. Broadening of the recording bandwidth leads to improve delay estim ation accuracy\, and improving accuracy of geodetic solution is expected. We performed experimental geodetic VLBI observation which used the high-sp eed sampler and recorder. In connection with it\, we optimized selection o f obaserved radio sources.\n\nhttps://events.saip.org.za/event/56/contribu tions/4575/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4575/ END:VEVENT BEGIN:VEVENT SUMMARY:Preliminary Results of VLBI observations of the Chang’E-3 Lunar Lander DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4576@events.saip.org.za DESCRIPTION:Speakers: Axel Nothnagel (Institute of Geodesy and Geoinformat ion\, University of Bonn)\, Rüdiger Haas (Chalmers University of Technolo gy)\nThe successful deployment of the Chang’E-3 Lander on the Moon on De c 14th\, 2013 has opened a new window for VLBI observations of the Moon. F ollowing 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 July 2014 to December 2015\, the Chang ’E-3 Lander was observed successfully during several 24-hour sessions. M ore than 10 stations distributed all around the world participated in each observing session. In this paper\, correlation results of the Beijing Aer ospace Control Center (BACC) for sessions in 2014 are presented\, concent rating on the software correlator\, key algorithms and observable accuracy analysis.\nBSCS(BACC Software Correlator System) is designed to run on Be owulf clusters consisting of commodity machines with parallel processing a lgorithms adopted in the software. \nFor the OCEL observations\, the Delta DOR mode was adopted\, which means a sequence of "Quasar - ChangE'3 - Quas ar". Here\, quasars with small separation angles are preferred to elimina te common errors as much as possible. The ChangE'3 Lander is equipped with an X-band transponder which transfers an X-band carrier and four DOR tone s at +/-19.25 MHz and +/-3.85 MHz in coherent modes. With a spanned bandwi dth of 38.5 MHz\, DOR tones are recorded in five different channels. Phase calibration (PCAL) is used to remove any offset in phase due to the BBCs electronics of different channels. When the phases of the PCAL tones are t oo noisy\, a strong calibrator is used to manually specify the phase of ea ch channel. The group delay is computed by bandwidth synthesis. The prelim inary accuracy analysis shows that the delay observables of Chang'E-3 are better than 1 ns\, depending on the signal-to-noise ratio of the different baselines.\n\nhttps://events.saip.org.za/event/56/contributions/4576/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4576/ END:VEVENT BEGIN:VEVENT SUMMARY:Tidal atmospheric loading and VLBI DTSTART;VALUE=DATE-TIME:20160317T130000Z DTEND;VALUE=DATE-TIME:20160317T131500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4577@events.saip.org.za DESCRIPTION:Speakers: Anastasiia Girdiuk (TU Wien)\nThis presentation is d edicated to the influence of diurnal atmosphere-ocean dynamics on Earth ro tation and loading effects as observed by Very Long Baseline Interferometr y. The first part focuses on the rotational signals associated with atmosp heric tides\, comprising small but non-negligible oscillations in the orde r 5 Μas. Here\, we compare tidally analysed VLBI observations against est imates from different providers of numerical weather models. We also discu ss the complexity of the issue that must make allowance for indirect effec ts due to tidal pressure variations acting on the ocean.\nIn the second pa rt\, we are investigating loading signals caused by atmospheric tides and the associated mass variations in the ocean. Different models of the effec t are compared with respect to their performance in a VLBI analysis\, and strategies how to apply consistent corrections for the atmosphere and the ocean are discussed. Moreover\, we also show VLBI results for two gravitat ional ocean tide models\, FES2004 and FES2012\, where the latter benefits from a much finer horizontal resolution and an improved description of hyd rodynamic processes.\n\nhttps://events.saip.org.za/event/56/contributions/ 4577/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4577/ END:VEVENT BEGIN:VEVENT SUMMARY:High-speed data playback of VLBI hardware correlator DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4578@events.saip.org.za DESCRIPTION:Speakers: Jiangying Gan (Shanghai Astronomical Observatory\,CA S)\nVLBI(Very Long Baseline Interferometry) is an important radio astronom y\ntechnology\, is widely used in deep-space probers high-precision measur ement. The correlator as the core data pre-processing equipment of VLBI\, its performance is very important. At present\, China VLBI data acquisitio n system (CDAS) can collect\ndata 2Gbps\, and multiband combination can re ach 16Gbps or 32Gbps. For ensure the requirements of high-speed and high-p recision\, there used Uniboard as the hardware platform\, used 10G Etherne t as the data playback interface and 1G Ethernet as the control interface\ , research the VLBI data playback which speed up to 4Gbps for single CDAS\ , and design some pre-processing method just like data correct and data de code specific to the VLBI data characteristic. Now we have finished the pr eliminary system\, and there will show the design and some results.\n\nhtt ps://events.saip.org.za/event/56/contributions/4578/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4578/ END:VEVENT BEGIN:VEVENT SUMMARY:WG on Galactic Aberration (WG8) meeting DTSTART;VALUE=DATE-TIME:20160314T163000Z DTEND;VALUE=DATE-TIME:20160314T180000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4579@events.saip.org.za DESCRIPTION:https://events.saip.org.za/event/56/contributions/4579/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4579/ END:VEVENT BEGIN:VEVENT SUMMARY:Asia-Oceania VLBI Group for Geodesy and Astrometry (AOV) meeting DTSTART;VALUE=DATE-TIME:20160315T173000Z DTEND;VALUE=DATE-TIME:20160315T190000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4580@events.saip.org.za DESCRIPTION:https://events.saip.org.za/event/56/contributions/4580/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4580/ END:VEVENT BEGIN:VEVENT SUMMARY:IVS Analysis Workshop DTSTART;VALUE=DATE-TIME:20160318T070000Z DTEND;VALUE=DATE-TIME:20160318T103000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4581@events.saip.org.za DESCRIPTION:https://events.saip.org.za/event/56/contributions/4581/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4581/ END:VEVENT BEGIN:VEVENT SUMMARY:VGOS Technical Committee (VTC) meeting DTSTART;VALUE=DATE-TIME:20160318T120000Z DTEND;VALUE=DATE-TIME:20160318T133000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4582@events.saip.org.za DESCRIPTION:https://events.saip.org.za/event/56/contributions/4582/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4582/ END:VEVENT BEGIN:VEVENT SUMMARY:WG on ICRF3 meeting DTSTART;VALUE=DATE-TIME:20160318T140000Z DTEND;VALUE=DATE-TIME:20160318T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4583@events.saip.org.za DESCRIPTION:https://events.saip.org.za/event/56/contributions/4583/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4583/ END:VEVENT BEGIN:VEVENT SUMMARY:IVS Directing Board meeting DTSTART;VALUE=DATE-TIME:20160319T070000Z DTEND;VALUE=DATE-TIME:20160319T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4584@events.saip.org.za DESCRIPTION:https://events.saip.org.za/event/56/contributions/4584/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4584/ END:VEVENT BEGIN:VEVENT SUMMARY:Registration DTSTART;VALUE=DATE-TIME:20160313T140000Z DTEND;VALUE=DATE-TIME:20160313T180000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4585@events.saip.org.za DESCRIPTION:https://events.saip.org.za/event/56/contributions/4585/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4585/ END:VEVENT BEGIN:VEVENT SUMMARY:Icebreaker Reception DTSTART;VALUE=DATE-TIME:20160313T160000Z DTEND;VALUE=DATE-TIME:20160313T180000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4586@events.saip.org.za DESCRIPTION:https://events.saip.org.za/event/56/contributions/4586/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4586/ END:VEVENT BEGIN:VEVENT SUMMARY:Closing Remarks DTSTART;VALUE=DATE-TIME:20160317T144500Z DTEND;VALUE=DATE-TIME:20160317T150000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4587@events.saip.org.za DESCRIPTION:Speakers: Axel Nothnagel (Institute of Geodesy and Geoinformat ion\, University of Bonn)\nhttps://events.saip.org.za/event/56/contributio ns/4587/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4587/ END:VEVENT BEGIN:VEVENT SUMMARY:INVITED TALK: Current Trends and Challenges in Satellite La ser Ranging DTSTART;VALUE=DATE-TIME:20160314T071500Z DTEND;VALUE=DATE-TIME:20160314T074000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4588@events.saip.org.za DESCRIPTION:Speakers: Graham Appleby (NERC Space Geodesy Facility\, Herstm onceux\, UK)\nSatellite 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 de fine the International Terrestrial Reference Frame (ITRF)\, which is the b asis upon which many aspects of global change over space\, time\, and evol ving technology are measured\; with VLBI the two techniques define the sca le of the ITRF\; alone the SLR technique defines its origin (geocentre). T he importance of the reference frame has recently been recognized at inter -governmental level through the United Nations\, which adopted in February 2015 the Resolution ‘Global Geodetic Reference Frame for Sustainable De velopment.’ \n\nLaser Ranging provides precision orbit determination and instrument calibration/validation for satellite-borne altimeters for the better understanding of sea level change\, ocean dynamics\, ice mass-balan ce\, and terrestrial topography. It is also a tool to study the dynamics o f the Moon and fundamental constants and theories. With the exception of t he currently in-orbit GPS constellation\, all GNSS satellites now carry re tro-reflectors for improved orbit determination\, harmonization of referen ce frames\, and in-orbit co-location and system performance validation\; t he next generation of GPS satellites due for launch from 2019 onwards will also carry retro-reflectors. The ILRS delivers weekly realizations that a re accumulated sequentially to extend the ITRF and the Earth Orientation P arameter series with a daily resolution. SLR technology continues to evolv e toward the next generation laser ranging systems and it is expected to s uccessfully meet the challenges of the GGOS2020 program for a future Globa l Space Geodetic Network. Ranging precision is improving as higher repetit ion rate\, narrower pulse lasers and faster detectors are implemented with in the network. Automation and pass interleaving at some stations is expan ding temporal coverage and greatly enhancing efficiency. Discussions are o ngoing with some missions that will allow the SLR network stations to prov ide crucial\, but energy-safe\, range measurements to optically vulnerable satellites. New retroreflector designs are improving the signal link and enable daylight ranging that is now the norm for many stations. We will di scuss many of these laser ranging activities and some of the tough challen ges that the SLR network currently faces.\n\nhttps://events.saip.org.za/ev ent/56/contributions/4588/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4588/ END:VEVENT BEGIN:VEVENT SUMMARY:Difxcalc: Calc11 for the DiFX Correlator DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4589@events.saip.org.za DESCRIPTION:Speakers: David Gordon (NVI\, Inc./GSFC)\nDifxcalc is a versio n of calc11 modified specifically for the\nDiFX correlator. It is a replac ement for the calc9.1\n'calcserver' currently in use. To create difxcalc\, all\nof the Mark3 database handler calls were removed from calc11\nand ne w input\, output and initialization modules were\nwritten and the flow of the program was modified\nfor correlator usage. Difxcalc takes as its\ninp ut the .calc files that are created in the difx\nprocessing stream and dir ectly outputs the .im\ncorrelator model files. It can handle jobs with\nmu ltiple scans and multiple phase centers. Difxcalc\nalso contains near-fiel d models\, which will allow\neasier correlation of spacecraft or other obj ects in\nthe solar system. We will outline the structure of\ndifxcalc and list the differences from the calc9.1\n'calcserver' and from the calc11 da tabase version.\nResults of various tests and comparisons will also\nbe pr esented.\n\nhttps://events.saip.org.za/event/56/contributions/4589/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4589/ END:VEVENT BEGIN:VEVENT SUMMARY:Status of the X/S Source Catalog DTSTART;VALUE=DATE-TIME:20160317T071500Z DTEND;VALUE=DATE-TIME:20160317T073000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4590@events.saip.org.za DESCRIPTION:Speakers: David Gordon (NVI Inc./GSFC)\nThe current state of t he X/S source catalog is presented\nand compared to ICRF2. There are curre ntly ~60% more observations\nand ~30% more sessions than were used for ICR F2. An ICRF made\ntoday would have ~20% more sources than ICRF2 and the av erage inflated\nformal errors would be ~2.4 times better than ICRF2. Much of this\nimprovement has come from the VCS-II campaign on the VLBA\, in\nw hich the average inflated formal errors of 2062 sources were\nreduced by a factor of 3.7 and 324 new sources were added.\nAdditional new sources hav e come from the RDV/RV\, CRF\, AUST\, AUA\,\nand AOV sessions. In addition to the current\nstatus\, we will present some of the additional goals\nfo r the X/S catalog before ICRF3 in 2018. This includes\nimproving the posit ions of a limited number of sources\nfor Gaia alignment and for X/Ka compa risons.\n\nhttps://events.saip.org.za/event/56/contributions/4590/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4590/ END:VEVENT BEGIN:VEVENT SUMMARY:VLBI observations of GNSS signals on the baseline Hobart-Ceduna – First results DTSTART;VALUE=DATE-TIME:20160317T141500Z DTEND;VALUE=DATE-TIME:20160317T143000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4591@events.saip.org.za DESCRIPTION:Speakers: Andreas Hellerschmied (Technische Universität Wien) \nThe observation of GNSS satellites with the geodetic VLBI system is an i nteresting approach which offers a variety of new possibilities. Promising applications can be found\, among others\, in the field of inter techniqu e ties. Such observations provide possibilities to directly connect the dy namic GNSS and the kinematic VLBI reference frame\, which may result in im proved future ITRF realizations. In our research we are trying to apply ob servation strategies\, which are commonly used in geodetic VLBI\, i.e. the main observables are group delay values derived from direct observations and the subsequent correlations of GNSS satellite signals. However\, data acquisition schemes for VLBI satellite observations are still at an experi mental stage. Further research is required to establish an operational pro cess chain\, similar to that applied for standard observations of natural radio sources.\n\nWe successfully carried out several experiments in 2015 on the Australian baseline Ceduna-Hobart. During these sessions\, with a f ew hours duration each\, GNSS satellites (GLONASS and GPS) were observed i n the L1 and L2 band along with natural radio sources for calibrations. Al l experiments were based on VEX-formatted schedule files created with the satellite scheduling module in the Vienna VLBI Software (VieVS). These con trol files implement a satellite tracking scheme which is based on stepwis e antenna repositioning using sequences of discrete celestial coordinates. The recorded data were successfully correlated with the DiFX correlator s oftware in combination with a suitable input model for near field targets. A preliminary analysis of the group delay measurements derived with the A IPS software suite was carried out with VieVS. \n\nWithin this contributio n we will give an insight into the applied data acquisition schemes\, from scheduling\, over correlation to data analysis\, and we will present late st results.\n\nhttps://events.saip.org.za/event/56/contributions/4591/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4591/ END:VEVENT BEGIN:VEVENT SUMMARY:The progress of VLBI digital backend in SHAO DTSTART;VALUE=DATE-TIME:20160316T081500Z DTEND;VALUE=DATE-TIME:20160316T083000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4592@events.saip.org.za DESCRIPTION:Speakers: renjie zhu (Shanghai Astronomical Observatory\, Chin ese Academy of Science)\nAbstract: 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 Acq uisition System) have been installed in CVN VLBI stations and applied in s everal projects. This presentation will introduce the history\, the curren t status and the future of the VLBI digital backends developed by SHAO.\n\ nhttps://events.saip.org.za/event/56/contributions/4592/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4592/ END:VEVENT BEGIN:VEVENT SUMMARY:Operating Experience of Broadband Acquisition System on RT-13 Radi o Telescopes DTSTART;VALUE=DATE-TIME:20160314T120000Z DTEND;VALUE=DATE-TIME:20160314T121500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4593@events.saip.org.za DESCRIPTION:Speakers: Evgeny Nosov (IAA RAS)\nBroadband Acquisition System (BRAS) was designed to digitize wideband signals from receivers of radio telescopes\, pack the digital samples into VDIF frames and transmit them t hrough 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 p erforms regular observations with RT-13 equipped with BRAS. Besides\, BRAS has been used in several international observations. The talk will descri be both the structure and performance of BRAS as well as the operation res ults.\n\nhttps://events.saip.org.za/event/56/contributions/4593/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4593/ END:VEVENT BEGIN:VEVENT SUMMARY:E-GRIP: A Highly Elliptical Orbit Satellite Mission for Co-locatio n in Space DTSTART;VALUE=DATE-TIME:20160317T131500Z DTEND;VALUE=DATE-TIME:20160317T133000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4594@events.saip.org.za DESCRIPTION:Speakers: Markus Rothacher (ETH Zurich)\nIn 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 satell ites are allowing at present for VLBI observations. In order to cure this situation new satellite missions like GRASP are considered\, new observati on concepts like tracking of GNSS L-band signals were implemented\, and at some telescopes receiver chains were modified. However\, evaluating today ’s situation\, only a few experimental GNSS L-band observations were con ducted\, whereas the majority of radio telescopes participating in the IVS cannot observe these. Future VLBI observations to the proposed GRASP miss ion will be possible for nearly all radio telescopes but\, due to the low orbit\, only for short baselines.\nIn this presentation we will introduce a new mission: the Einstein Gravitational Red-shift Probe (E-GRIP). The sc ientific objectives of E-GRIP are the measurement of the space-time curvat ure around the Earth and the performance of multiple tests of general rela tivity. Therefore\, E-GRIP will fly in a highly eccentric orbit (e>0.6\, a pogee>35000km) and will carry a narrow- and a wide-angle microwave link (b oth at X- and K-band)\, two GNSS antennas\, an SLR retro-reflector array\, and a space hydrogen maser. Consequently\, E-GRIP could act as a co-locat ion satellite with optimal observation conditions for VLBI. Beyond a missi on overview\, we will present results from extended VLBI simulations conce rning link budget\, visibilities\, and achievable station coordinate resul ts. We will also discuss the benefits for VLBI compared to co-location on GRASP and on GNSS satellites in terms of visibility and station coordinate accuracy. In addition\, we will show the feasibility of co-located GNSS a nd SLR observations for this highly elliptical orbit.\n\nhttps://events.sa ip.org.za/event/56/contributions/4594/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4594/ END:VEVENT BEGIN:VEVENT SUMMARY:Vienna contribution to the ICRF3 DTSTART;VALUE=DATE-TIME:20160317T070000Z DTEND;VALUE=DATE-TIME:20160317T071500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4595@events.saip.org.za DESCRIPTION:Speakers: David Mayer (Technische Universität Wien)\nThe curr ent realisation of the celestial reference frame\, the ICRF2\, was publish ed 2009. Since then the VLBI technique evolved. New stations were implemen ted and the amount of data from the Southern Hemisphere increased dramatic ally. The demands on accuracy of the celestial reference frame are higher than ever\, with the GAIA mission providing a catalogue in the visible spe ctrum with comparable accuracy. These advances in the VLBI technique and n ew demands on accuracy entail the necessity of a new version of the celest ial reference frame which will be called ICRF3. We will report on the prog ress and plans of the Vienna group to estimate such a reference frame. Fur thermore\, we will discuss issues which arise during the estimation proces s such as a declination bias.\n\nhttps://events.saip.org.za/event/56/contr ibutions/4595/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4595/ END:VEVENT BEGIN:VEVENT SUMMARY:VLBI processing at ESOC\, the last piece for generating an indepen dent reference frame DTSTART;VALUE=DATE-TIME:20160316T123000Z DTEND;VALUE=DATE-TIME:20160316T124500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4596@events.saip.org.za DESCRIPTION:Speakers: Claudia Flohrer (ESOC - Navigation Support Office\, Darmstadt\, Germany)\nESOC’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 Supp ort Office has demonstrated its expertise in the processing of various spa ce-geodetic techniques\, such as GNSS\, SLR and DORIS and their combinatio n on the observation level. Nevertheless\, the last and vital piece missin g for the generation of an independent reference frame is VLBI\, which is required to define the Earth’s orientation. \nESOC’s Navigation Sup port Office is currently extending its expertise to VLBI processing and an alysis. We are enhancing the processing capabilities of our work horse sof tware package NAPEOS for VLBI tracking data. \nThis capability will put us in the position to combine all space-geodetic techniques with one single software package at the observation level. The combination of the differen t techniques brings together the strengths of the individual techniques. The satellite techniques GNSS\, SLR and DORIS are able to determine the Ea rth’s centre of mass\, the X- and Y-pole offsets and rates and the Lengt h of Day. However\, VLBI is the only technique able to accurately determin e universal time (UT1-UTC) and the celestial pole offsets.\nThe processing of VLBI tracking data will complete ESOC’s capabilities in generating a n independent reference frame for ESA missions. It will allow us to contri bute to the IERS service for UT1-UTC and for the celestial pole offset\, w hilst at the same time to reduce our dependency on this service. And last but not least our software NAPEOS would become the first software combinin g all four geodetic techniques on the observation level and thus supportin g GGOS\, the Global Geodetic Observing System\, to get a better understand ing of our living planet.\nWe will present an overview of the current stat us of the VLBI processing at ESOC and will give an outlook on our future p lans.\n\nhttps://events.saip.org.za/event/56/contributions/4596/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4596/ END:VEVENT BEGIN:VEVENT SUMMARY:Progress on VLBI Ecliptic Plane Survey DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4612@events.saip.org.za DESCRIPTION:Speakers: Fengchun Shu (Shanghai Astronomical Observatory)\nTh e goal of VLBI Ecliptic Plane Survey (VEPS) is to increase the number of c alibrator radio sources within 7.5 degree of the ecliptic plane by surveyi ng a complete sample of sources with single dish flux densities at 5 GHz g reater than 50 mJy. A dense grid of calibrators along ecliptic plane with very accurate coordinates is required for many applications\, including ob servations of spacecrafts in the phase referencing mode. Such observations are used for spacecraft navigation\, improvement of planet ephemerides an d determination of the Moon’s libration. The VEPS observing program is u nderway with participation of 3 core Chinese VLBI stations: Seshan25\, Kun ming and Urumqi\, and several international stations that join on ad hoc b asis. We will present the current status of the VEPS observing program and show preliminary results.\n\nhttps://events.saip.org.za/event/56/contribu tions/4612/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4612/ END:VEVENT BEGIN:VEVENT SUMMARY:Completing the K-band Celestial Reference Frame in the North. DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4597@events.saip.org.za DESCRIPTION:Speakers: Aletha de Witt (Hartebeesthoek Radio Astronomy Obser vatory)\nK-band (22 GHz) radio observations have the potential to form the basis for the most accurate celestial reference frame ever constructed. R elative to the standard S/X (2.3/8.4 GHz) observing bands\, K-band is expe cted 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 and should also be advantageous in ty ing the VLBI radio frame to the Gaia optical frame. The current K-band cat alogue consists of only 274 sources from a few VLBA sessions and uncertain ties in source positions at the ~100 micro-arcsecond level. Modern 2 Gbps data rates are 16 times better than previous observations\, yielding a fou r fold increase in sensitivity. Southern observations to reduce astrometri c systematics and to complete the sky coverage at K-band are under way. Ho wever\, new astrometric and imaging observations are also required in the North to improve K-band precision and spatial coverage\, and to map the in trinsic source structure so that their astrometric quality can be evaluate d. A proposal for astrometric and imaging observations using the Very Long Baseline Array (VLBA) at K-band have been approved. We discuss some of o ur first results from our K-band VLBA campaign.\n\nhttps://events.saip.org .za/event/56/contributions/4597/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4597/ END:VEVENT BEGIN:VEVENT SUMMARY:Optimizing the African VLBI Network for Astronomy and Geodesy DTSTART;VALUE=DATE-TIME:20160315T102500Z DTEND;VALUE=DATE-TIME:20160315T104000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4598@events.saip.org.za DESCRIPTION:Speakers: Aletha de Witt (Hartebeesthoek Radio Astronomy Obser vatory)\nCurrently SKA-SA and HartRAO are converting the redundant 34-m te lecommunications antenna in Ghana to a radio telescope. The Ghanaian radi o 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 bee n destroyed). It is proposed that more of these can be converted and added to the AVN. Each addition will improve the present global VLBI networks\ ; some will have greater impact than others. Currently there are plans\, and limited funding\, to convert two more antennas in Kenya and Zambia. I t is presently proposed that each of these new AVN stations will be equipp ed with the same receivers as Ghana\, a 5 and 6.7 GHz receivers and later a 1.4 - 1.7 GHz receiver. New radio telescopes may also be built. However\ , no significant evaluation of the optimization of the AVN has been compl eted. Such an analysis will inform which to convert first\, where to build new stations and what next-generation instruments and receivers they shou ld have.\n\nIn this presentation we re-visit the scientific justifications for the AVN including both astronomical and geodetic science. We analyse weather station\, GPS and satellite weather data for each telecommunicati ons antenna in Africa to determine the frequency limitations at each. A Go ogle-based assessment of the possible radio frequency interference environ ment is made. We also generate UV-coverage plots for existing VLBI network s together with potential AVN locations to get an idea of the density and distribution of the UV tracks and the imaging quality that may be obtained . In addition we simulate some geodetic observations to asses the contribu tion of AVN antennas to geodetic VLBI products in current and future netwo rks. With this data we attempt to optimize the AVN for each science case\, both astronomical and geodetic. We discuss the potential contributions th e AVN might make to current global geodetic and astronomical experiments\, as well as what a stand-alone AVN can do. We also discuss possible statio ns of interest for high-frequency radio astronomy and astrometry\, possibl e sites for future VGOS antennas and where collocation of other geodetic i nstruments can be implemented.\n\nhttps://events.saip.org.za/event/56/cont ributions/4598/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4598/ END:VEVENT BEGIN:VEVENT SUMMARY:El Nino and VLBI measured LOD DTSTART;VALUE=DATE-TIME:20160317T121500Z DTEND;VALUE=DATE-TIME:20160317T123000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4599@events.saip.org.za DESCRIPTION:Speakers: John Gipson (NVI Inc/GSFC NASA)\nShort term (daily t o annual) variations in LOD are highly correlated with Atmospheric Angular Momentum. It has been known since the late 1980s and early 1990s that yo u 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 i s still developing\, and is one of the strongest ever recorded. I look at correlation with Modified Enso Index and VLBI measured LOD. I also discus s the cumulative effect of the El Nino on UT1.\n\nhttps://events.saip.org. za/event/56/contributions/4599/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4599/ END:VEVENT BEGIN:VEVENT SUMMARY:Unveiling the VGOS Signal Chain at the Kokee Park Geophysical Obse rvatory DTSTART;VALUE=DATE-TIME:20160314T101500Z DTEND;VALUE=DATE-TIME:20160314T103000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4600@events.saip.org.za DESCRIPTION:Speakers: Ganesan Rajagopalan (MIT Haystack Observatory)\nMIT Haystack Observatory\, as part of the NASA Space Geodesy Program\, is deli vering the first VGOS-compliant Signal Chain to the Kokee Park Geophysical Observatory (KPGO)\, Hawaii\, and will soon be integrating and commission ing the KPGO 12-m station.\n\nWe will describe the Signal Chain subsystems and highlight the design and performance of the cryogenically cooled fron tend. This incorporates a broadband Quad Ridge Flared Horn (QRFH) feed and Indium Phosphide low-noise amplifiers\, both developed by the California Institute of Technology. The talk will also cover the design and performan ce of a Cable Delay Measurement System (CMDS) and the salient features of a Calibrator module that enables phase and noise calibration as well as th e cable delay measurements.\n\nWe expect to present some early results fro m the commissioning phase of KPGO including aperture efficiency\, SEFD acr oss the band\, and delay stability. We will also discuss possible approach es towards RFI mitigation\, enhanced receiver sensitivity and dynamic rang e\, and other forward-looking technologies.\n\nhttps://events.saip.org.za/ event/56/contributions/4600/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4600/ END:VEVENT BEGIN:VEVENT SUMMARY:IVS Primary Data Center and Analysis Center at BKG DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4601@events.saip.org.za DESCRIPTION:Speakers: Dieter Ullrich (BKG)\nThe BKG (Federal Agency for Ca rtography and Geodesy) Data Center is one \nof the three IVS Primary Data Centers. It archives\nall VLBI related data of IVS components and provides public access for \nthe community.\n\nThe VLBI Analysis Group of BKG is p art of the jointly operated IVS \nAnalysis Center of BKG and the Institute for Geodesy and\nGeoinformation of the University of Bonn. The BKG is res ponsible for the \ncomputation of time series of earth orientation paramet ers and\ntropospheric parameters\, the generation of SINEX files for 24 ho urs VLBI \nsessions and Intensive sessions\, and quarterly updated global solutions\nfor terrestrial reference frame and celestial reference frame r ealizations.\n\nhttps://events.saip.org.za/event/56/contributions/4601/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4601/ END:VEVENT BEGIN:VEVENT SUMMARY:New generation VLBI: Intraday UT1 estimations DTSTART;VALUE=DATE-TIME:20160315T081500Z DTEND;VALUE=DATE-TIME:20160315T083000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4602@events.saip.org.za DESCRIPTION:Speakers: Alexander Ipatov (Institute of Applied Astronomy RAS )\nIAA finished work on creation of new generation radio interferometer wi th 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 polarizations. Sessions consisted of about 60 scans with 22 seconds minimum scan duration. Stations broadband acquisition sys tems generate 1.5-3 TB data per session which are transferred via Internet to the IAA FX correlator. Accuracy of group delay in single channel was 1 0-20 ps what allows to use every single channel observations for geodetic analysis without synthesis. 156 single channel NGS-cards were obtained in total. UT1-UTC estimations give 19 µs RMS of differences when comparing w ith the IERS finals.\n\nhttps://events.saip.org.za/event/56/contributions/ 4602/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4602/ END:VEVENT BEGIN:VEVENT SUMMARY:Operational VGOS Scheduling DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4603@events.saip.org.za DESCRIPTION:Speakers: Bill Petrachenko (Natural Resources Canada)\nThe VLB I Global Observing System (VGOS) has been designed to take advantage of ad vances in data bandwidths\, allowing for smaller and faster antennas\, wid er 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 fo r continuous observations which presents new operational challenges. As th e source-based strategy is independent of the observing network\, there ar e operational advantages which allows for more flexible scheduling of cont inuous VLBI observations. Using VieVs\, Monte Carlo simulations of several schedules are presented and compared with previous VGOS studies.\n\nhttps ://events.saip.org.za/event/56/contributions/4603/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4603/ END:VEVENT BEGIN:VEVENT SUMMARY:INVITED TALK: Activities of the IERS Working Group on Site Survey and Co-location DTSTART;VALUE=DATE-TIME:20160315T090000Z DTEND;VALUE=DATE-TIME:20160315T092500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4604@events.saip.org.za DESCRIPTION:Speakers: Sten Bergstrand (SP Technical Research Institute of Sweden)\nThe combination of space geodetic solutions is critically reliant on the availability of local tie vectors\, which are the relative positio ns of the reference points of co-located space geodetic\ninstruments deter mined by some survey technique. Tie vectors enter the combination of space geodetic solutions effectively as a fifth technique and are not only nece ssary for rigorous terrestrial reference frame realization but also serve to highlight the presence of technique- and/or site-specific biases.\nWith the ultimate objective of improving the accuracy of tie vectors as well a s the consistency of space geodetic solutions\, the Working Group (WG) pro vides an authoritative source of surveying methodology advice\, promotes t echnical discussion\, provides a forum for the evaluation of existing and new procedures and analysis strategies\, and supports the exchange of rele vant information across GGOS and between the IAG technique services.\nThe working group also acts as an entity of the GGOS Bureau of Networks and Ob servations under the IERS name\, as well as of the IAG Subcommision 1.2 as WG 1.2.1.\n\nIn the presentation\, we give examples of recent and current work on \n• adequate terminology when discussing site surveying and local ties\n• automatic reference point determination\n• telesco pe deformation\n• observations of common baseline components\n• insights to DORIS\, GNSS\, and SLR work related to local ties\n\nhttps://e vents.saip.org.za/event/56/contributions/4604/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4604/ END:VEVENT BEGIN:VEVENT SUMMARY:VGOS Source Selection Criteria DTSTART;VALUE=DATE-TIME:20160315T071500Z DTEND;VALUE=DATE-TIME:20160315T073000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4605@events.saip.org.za DESCRIPTION:Speakers: Bill Petrachenko (Natural Resources Canada)\nSource structure has long been recognized as a significant risk factor for the br oadband method. The issue of greatest concern is that structure related ph ases and delays will lead to cycle slips during broadband phase connection . These errors will be difficult to handle since they are both subtle to d etect and almost certainly impossible to correct after the fact.\n\nAs the advent of VGOS operations draws near\, criteria will be needed to generat e lists of candidate VGOS sources that are at the same time strong enough to be detected and simple enough not to cause broadband phase connection e rrors. \n\nThe purpose of this study is to propose useful VGOS source sele ction criteria and to understand their relation to broadband frequency seq uences\, source lists\, and geodetic/astrometric performance. In order to increase the number of available sources\, an attempt will be made to find frequency sequences that operate reliably below the typical VGOS flux cut -off of 250 mJ. Candidate source lists will be generated using the Bordeau x VLBI Image Data Base (BVID) as input and geodetic/astrometric performanc e will be predicted using the VieVS Monte Carlo simulator.\n\nhttps://even ts.saip.org.za/event/56/contributions/4605/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4605/ END:VEVENT BEGIN:VEVENT SUMMARY:Aspects of relativistic geodesy within the framework of VLBI and V GOS DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4606@events.saip.org.za DESCRIPTION:Speakers: Ludwig Combrinck (HartRAO)\nRelativistic geodesy is typically seen as a new type of gravity potential measurement technique us ing 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 t he Earth\, therefore the term relativistic geodesy is re-assessed. The pos sible contributions of VLBI stations in the framework of GGOS using VGOS a ntennas and modernized geophysical and timing equipment are described. Tim e transfer using VLBI and GNSS\, integrated geodetic systems\, future spac e based missions and Lunar missions all have a roll to play in a relativis tic geodesy which extends to the solar system and beyond. Instrumental and network requirements are considered\, error sources and error budgets are discussed.\n\nhttps://events.saip.org.za/event/56/contributions/4606/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4606/ END:VEVENT BEGIN:VEVENT SUMMARY:First implementations of new monitoring capabilities as extension to the e-RemoteCtrl software DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4607@events.saip.org.za DESCRIPTION:Speakers: Alexander Neidhardt (Technische Universität Münche n\, Geodätisches Observatorium Wettzell)\nA new release of the telescope control software e-RemoteCtrl\, which is designed to run VLBI observations remotely\, has been extended with new monitoring capabilities. \nThe soft ware extension is a test for further monitoring and control infrastructure s for complete VLBI networks. The poster shows Ideas and already implement ed elements.\n\nhttps://events.saip.org.za/event/56/contributions/4607/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4607/ END:VEVENT BEGIN:VEVENT SUMMARY:Near-field VLBI for Planetary Science DTSTART;VALUE=DATE-TIME:20160317T133000Z DTEND;VALUE=DATE-TIME:20160317T134500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4608@events.saip.org.za DESCRIPTION:Speakers: Bob Campbell (JIVE)\nNear-field VLBI is a radio astr onomical technique that\, when applied to observations of spacecraft\, pro vides unique insights into those areas of a space mission's scientific pro gramme requiring precise determination of the spacecraft's lateral positio n on the celestial sphere and its radial velocity. This technique was pio neered 30 years ago with the tracking of VEGA balloons to determine the wi nd field in the atmosphere of Venus.\n\n The Planetary Radio Interferomet ry and Doppler Experiment (PRIDE) exploits near-field VLBI for accurate es timation of the state-vector of a spacecraft using arrays of Earth-based r adio telescopes. PRIDE has proven to be very efficient in a number of rec ent VLBI experiments\, starting with tracking the descent and landing of t he Huygens Probe in the atmosphere of Saturn's moon Titan. PRIDE has cond ucted several observations of ESA's Venus Express mission for investigatio ns ranging from its aero-braking maneuvers through the Venusian atmosphere to the scintillation structure in the interplanetary medium. On 28-29 De cember 2013\, a global VLBI campaign including over 30 stations was conduc ted to observe Mars Express during its close fly-by of Phobos. PRIDE prov ided measurements of the spacecraft's differential lateral position relati ve to the ICRF background extragalactic radio sources with an accuracy of 100 to 10 μas (1σ RMS) over integration times from 60 to 1000 s. \n\n W ith such accuracy\, PRIDE can address scientific objectives spanning\nthe improvement of satellite ephemerides\, ultra-precise celestial mechanics\, the study of planetary atmospheres via occultations\, and the characteriz ation solar-wind and ionospheric effects on spacecraft transmissions. Imp roved satellite ephemerides would in turn allow a planetary system to be t ied more firmly into the extragalactic reference frame\, providing a major contribution to planetary geodesy and the definition of the Solar System reference system. \n\n In collaboration with other on-board radio science experiments of a planetary mission\, PRIDE enhances the overall mission's science return. We will review the technique of PRIDE and illustrate it s capabilities in multi-disciplinary applications for planetary science mi ssions.\n\nhttps://events.saip.org.za/event/56/contributions/4608/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4608/ END:VEVENT BEGIN:VEVENT SUMMARY:First results of the FAST-S/X-sessions with new VGOS antennas DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4609@events.saip.org.za DESCRIPTION:Speakers: Alexander Neidhardt (Technische Universität Münche n\, Geodätisches Observatorium Wettzell)\, Pablo de Vicente (Observatorio de Yebes (IGN))\nThe organization of first fast slewing observations with new VGOS antennas was decided during the VTC meeting at Ponta Delgada. Th e goal was to observe S/X-schedules regularly\, using the fast slewing cap abilities of the antennas as long as they are equipped with classic S/X-ca pabilities. The poster/presentation discusses and shows first results of t hese observations.\n\nhttps://events.saip.org.za/event/56/contributions/46 09/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4609/ END:VEVENT BEGIN:VEVENT SUMMARY:The German Antarctic Receiving Station O’Higgins and its VLBI-ca pabilities DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4610@events.saip.org.za DESCRIPTION:Speakers: Christian Plötz (Bundesamt für Kartographie und Ge odäsie)\nThe German Antarctic Receiving Station (GARS) O’Higgins starte d in the early 1990th with regular VLBI operations. Because of its remote position on the Antarctic Peninsula\, the VLBI observation was mostly rest ricted to the Antarctic summer month. New equipment\, a continuous operati on by the German Aerospace Center (DLR)\, and new realizations of observat ion schedules may open the door for regular observations over the whole ye ar. The poster shows the upgrades carried out in hard- and software and th e latest results.\n\nhttps://events.saip.org.za/event/56/contributions/461 0/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4610/ END:VEVENT BEGIN:VEVENT SUMMARY:Meeting of the Monitor and Control Infrastructure (MCI) group DTSTART;VALUE=DATE-TIME:20160314T163000Z DTEND;VALUE=DATE-TIME:20160314T180000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4611@events.saip.org.za DESCRIPTION:https://events.saip.org.za/event/56/contributions/4611/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4611/ END:VEVENT BEGIN:VEVENT SUMMARY:VLBI sources in optical and radio DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4613@events.saip.org.za DESCRIPTION:Speakers: César GATTANO (SYRTE - Observatoire de Paris)\nUnti l now\, the main criteria for selecting geodetic sources were based on ast rometric stability and structure at 8 GHz [Fey et al.\, 2015]. Other physi cal characteristics\, especially at other wave-lengths\, including the opt ical\, should also enter the selection procedure. To this aim\, we propose to summarize all known physical caracteristics\, thanks to the use of thr ee different catalogs : the Large Quasar Astrometric Catalogue [Souchay et . al.\, 2015]\, the Radio Fundamental Catalogue (Petrov\, http ://astrogeo .org/rfc/) and the Optical Characteristics of Astrometric Radio Sources [M alkin\, 2013]. We also bring radio stability criteria derived from our own VLBI analysis. With\nsuch a compilation\, we may identify new criterion f or geodetic VLBI targets.\n\nhttps://events.saip.org.za/event/56/contribut ions/4613/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4613/ END:VEVENT BEGIN:VEVENT SUMMARY:The variable Earth annual retrograde nutation DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4614@events.saip.org.za DESCRIPTION:Speakers: César GATTANO (SYRTE - Observatoire de Paris)\nVery Long Baseline Interferometry is the only technique that can estimate Eart h nutations with an accuracy under the milliarcsecond level. With 35 years of geodetic VLBI observations\, the principal nutation terms caused by lu ni-solar tides and geophysical response have been estimated. We focuse on the variabity. Two of them present very significant amplitude and phase va riations : the retrograde Free Core Nutation (FCN) at around 430 days peri od and the Annual Retrograde\nNutation (ARN). Despite progresses achievied in global circulation models\, the atmospheric and ocean excitation canno t account for that. In particular the ARN shows an amplitude modulation of approximately 6 years\, reminding the 6-year geomagnetc oscillation in Le ngth of Day (LOD). Therefore we investigate possible correlation of this modulation with the 6-year wave observed in LOD. More generally\, we sugge st that the nutation term variability may have deep Earth causes\, and can not be integrally attributed to surface mass redistribution.\n\nhttps://ev ents.saip.org.za/event/56/contributions/4614/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4614/ END:VEVENT BEGIN:VEVENT SUMMARY:Refinement of Rapid UT1 Estimation Derived from Tsukuba VLBI Measu rements after 2011 Earthquake DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4615@events.saip.org.za DESCRIPTION:Speakers: Gerald Engelhardt (BKG (Federal Agency for Cartograp hy and Geodesy))\nThe 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 coor dinates 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. \nSince 2012\, the VLBI group at BKG uses a method\, which solv es this problem. This procedure was refined with respect to a newly develo ped extrapolation to get most probable station positions of Tsukuba for th e epochs of the Intensive sessions. The procedure is explained and could b e successfully integrated into the technological process of operational an alysis of post-quake Intensive sessions with station Tsukuba.\n\nhttps://e vents.saip.org.za/event/56/contributions/4615/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4615/ END:VEVENT BEGIN:VEVENT SUMMARY:The Development of Hardware Correlator in SHAO DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4616@events.saip.org.za DESCRIPTION:Speakers: zhijun xu (Shanghai Astronomical Observatory\, CAS)\ nThe hardware correlator have been used in Chinese Chang'E missions. Recen tly\, a hardware correlator based on uniboard has been developed. This art icle presents the development of hardware correlator at SHAO and some resu lts.\n\nhttps://events.saip.org.za/event/56/contributions/4616/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4616/ END:VEVENT BEGIN:VEVENT SUMMARY:KPGO 12m Signal Chain Update\, First Light and Beyond DTSTART;VALUE=DATE-TIME:20160314T100000Z DTEND;VALUE=DATE-TIME:20160314T101500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4617@events.saip.org.za DESCRIPTION:Speakers: Chet Ruszczyk (MIT Haystack Observatory)\nThe Kokee Park Geophysical Observatory's 12m is expected to see First \nLight early 2016.  A description of the integration and testing that \nwas performed at MIT Haystack Observatory before shipping \nthe signal chain is describe d.  This is followed by a summary of the \nteams work that had to occur b efore first light and the initial \nresults. \n\nBeyond KPGO first light f ocuses on the commissioning summary followed \nby the road to the second i nstallation at McDonald Texas.  Here the \nfocus shifts to the expected e nhancements to the signal chain and retrofit plans for KPGO.\n\nhttps://ev ents.saip.org.za/event/56/contributions/4617/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4617/ END:VEVENT BEGIN:VEVENT SUMMARY:Venus and Mars Express spacecraft observations with Wettzell radio telescopes DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4618@events.saip.org.za DESCRIPTION:Speakers: Alexander Neidhardt (Technische Universität Münche n\, Geodätisches Observatorium Wettzell)\nThe 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 sessi ons to routinely run the processing and analysis pipeline. Recorded data w ere transferred from Wettzell to the JIVE cooperation partners for correla tion and analysis. A high dynamic range of the detections allowed us to ac hieve a milliHz level of the spectral resolution accuracy and extract the phase of the spacecraft signal carrier line. Several physical parameters c an be determined from these observational results with more observational data collected. Apart from other results\, the measured phase fluctuations of the carrier line at different time scales can assess to determine the influence of the Solar wind plasma density fluctuations on the accuracy of the astrometric VLBI observations.\n\nhttps://events.saip.org.za/event/56 /contributions/4618/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4618/ END:VEVENT BEGIN:VEVENT SUMMARY:Status Report Norwegian Mapping Authority Analysis Center DTSTART;VALUE=DATE-TIME:20160316T101000Z DTEND;VALUE=DATE-TIME:20160316T102500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4619@events.saip.org.za DESCRIPTION:Speakers: Ann-Silje Kirkvik (Norwegian Mapping Authority)\nThe Norwegian Mapping Authority has been using GEOSAT to analyze 24-hour VLBI sessions. GEOSAT was originally developed by Per Helge Andersen at the No rwegian Research Defense Establishment\, but is now owned by Norwegian Map ping Authority. GEOSAT is a multi-technique geodetic analysis software tha t aims to process observations from VLBI\, SLR\, GNSS and DORIS to improve the global geodetic reference frame. \nTo validate the VLBI model in GEOS AT the Norwegian Mapping Authority tried to contribute to the next ITRF so lution but encountered some major problems too close the final deadline. H owever\, the Norwegian Mapping Authority successfully participated the VLB I Software Comparison Campaign 2015. A quick overview of the recent activi ties\, challenges\, priorities\, status and future plans for the GEOSAT pr oject at the Norwegian Mapping Authority will be presented.\n\nhttps://eve nts.saip.org.za/event/56/contributions/4619/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4619/ END:VEVENT BEGIN:VEVENT SUMMARY:The impact of the broadband VLBI on the next decade DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4626@events.saip.org.za DESCRIPTION:Speakers: Kazuhiro Takefuji (NICT)\, Mamoru Sekido (National I nstitute of Information and Communications Technology)\nThe Kashima 34 m r adio telescope\, the cassegrain optics is currently realized 3.2GHz to 14 GHz receiver system by installing the NINJA feed. Furthermore a direct sam pler GALAS easily connect four 1GHz bandwidth without any analogue frequen cy converter and phase-cal.\n VGOS\, EHT and other astronomy VLBI highly d emand broadband system for better delay determination\, shorter integratio n time and better SNR.\n We will report our progress of developing broadba nd system and recent results.\n\nhttps://events.saip.org.za/event/56/contr ibutions/4626/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4626/ END:VEVENT BEGIN:VEVENT SUMMARY:How to register a VGOS-radio telescope at ITU and why it is import ant DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4656@events.saip.org.za DESCRIPTION:Speakers: Brian Corey (MIT Haystack Observatory)\, Vincenza TO RNATORE (Politecnico di Milano - DICA)\nA number of new VGOS-radio telesco pes are built or under construction\, partly at new locations. VGOS radio telescopes enable observations in the range of 2-14 GHz. For this reason V GOS radio telescopes are much more receptive for unwanted radio frequency interference. RFI originates from local transmitting devices as well as fr om space based transmitting systems. Some space-borne devices may cause de trimental radiation to VGOS receivers. It is important to register the new sites at ITU in order to obtain administrative protection for the radio t elescope sites and to avoid direct illuminations by strong radars. This co ntributions explains how to achieve the registration.\n\nhttps://events.sa ip.org.za/event/56/contributions/4656/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4656/ END:VEVENT BEGIN:VEVENT SUMMARY:The new Geodetic Research Data Management System at HartRAO DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4620@events.saip.org.za DESCRIPTION:Speakers: Glenda Coetzer (HartRAO)\nThe Hartebeesthoek Radio A stronomy Observatory (HartRAO) participates in astronomic\, astrometric an d geodetic Very Long Baseline Interferometry (VLBI) observations using bot h 26- and 15-m diameter radio telescopes. These as well as additional geod etic data from a Satellite Laser Ranger (SLR)\, Global Navigation Satellit e System (GNSS)\, Met4 weather stations\, a new seismic network must be st ored at HartRAO and made available to the scientific community. Some data are e-transferred to correlators\, analysis centres and space geodesy data providers\, while others are processed locally to produce basic data prod ucts. The African VLBI Network (AVN) data storage and correlation will occ ur at HartRAO as well.\n\nThe AVN correlation and seismic network will gen erate large volumes of raw data to be stored and archived at HartRAO. The current data storage systems are distributed and outdated\, and management systems currently being used will not be able to handle the additional la rge data volumes. This necessitates the design and implementation of a new \, next-generation research data management system which combines all the datasets into one database\, as well as cater for current and future data volume requirements. \n\nIn terms of processing\, HartRAO is collaborating with the CSIR Centre for High Performance Computing and we will operate a Dell Westmere cluster containing 2880 CPU cores (61.5 TFlops)\n\nProfessi onals from different disciplines will be working together in designing and implementation of the new data and processing systems. A short overview o f the project as well as a progress report will be presented.\n\nhttps://e vents.saip.org.za/event/56/contributions/4620/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4620/ END:VEVENT BEGIN:VEVENT SUMMARY:The Statistic Analysis of Atmospheric Effects of Differential VLBI DTSTART;VALUE=DATE-TIME:20160317T100000Z DTEND;VALUE=DATE-TIME:20160317T101500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4621@events.saip.org.za DESCRIPTION:Speakers: Shuangjing Xu (Shanghai Astronomical Observatory)\nD uring the Chinese Lunar Mission hundreds of VLBI observations have been ca rried\, 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 differe nt time intervals and doing self-calibration each other in phase-referenci ng style to investigate the relationship of differential atmospheric delay and different “time-switching”. In this report we will present our pr imary result.\n\nhttps://events.saip.org.za/event/56/contributions/4621/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4621/ END:VEVENT BEGIN:VEVENT SUMMARY:Automated simultaneous local ties with GNSS and robot tachymeter DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4622@events.saip.org.za DESCRIPTION:Speakers: Sten Bergstrand (SP Technical Research Institute of Sweden)\nWe have used GPS-based local-tie measurements simultaneously with geo VLBI observations since 2008 during every geodetic VLBI session at Me tsähovi. This system uses gimbal-mounted GNSS-antennas that are mounted o n the reflector of the Metsähovi 14 m radio telescope. A similar system h as been installed in 2013 at the Onsala 20 m radio telescope and been used for a large number of VLBI sessions\, including e.g. the 15 day long CONT 14 campaign. In order to verify the results of the two systems\, we perfor med a dedicated measurement campaign in the framework of the SIB60 project \, involving both Metsähovi and Onsala. During this campaign the local ti es at the two stations were measured simultaneously during two VLBI sessio ns in August and September 2015 where both stations participated. The robo t tachymeter monitoring system HEIMDALL was used for the automated classic al monitoring of the telescopes at both stations. Moreover\, additional lo cal terrestrial measurements were performed several times to derive the fu ll IVS-IGS local ties at both sites. The kinematic GPS measurement at the two stations were analyzed with two individually developed analysis progra ms.\nWe present here the preparations of the campaign\, the measurement pr ocess\, and preliminary results.\n\nhttps://events.saip.org.za/event/56/co ntributions/4622/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4622/ END:VEVENT BEGIN:VEVENT SUMMARY:Current status of the development and performance of OCTAVE-DAS an d Correlator System DTSTART;VALUE=DATE-TIME:20160314T121500Z DTEND;VALUE=DATE-TIME:20160314T123000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4623@events.saip.org.za DESCRIPTION:Speakers: Tomoaki Oyama (NAOJ)\nThe new VLBI observing system (OCTAVE-DAS) have been developed based on the VSI-H and VDIF specification s 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 GH z and have DBBC functions for VGOS (VLBI Global Observing System)\, 2) a c onverter (OCTAVIA and OCTAVIA2) between one 10 GigE port and four 2 Gbps i nput and output ports conformable to VSI-H\, and 3) new recorders (OCTADIS K\, OCTADISK2 and VSREC)have functions of both recording and playing at a maximum rate of 32 Gbps and 4) Gbit realtime correlator (OCTACOR) and soft ware correlator system (OCTACOR2) using GICO3 was developed by NICT. We ha ve been upgrading the software correlator using GPGPU technology. These O CTAVE-DAS are connected via >10 GigE network with VDIF and VSI specificati ons. These components have been used for VERA\, JVN (Japanese VLBI network ) and Daejeon Correlator. We will report on a installation plan and a 4-ye ar progress since the 7th IVS general meeting and results of test and scie ntific broad-band(>8 Gbps) VLBI observations using the OCTAVE-DAS.\n\nhttp s://events.saip.org.za/event/56/contributions/4623/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4623/ END:VEVENT BEGIN:VEVENT SUMMARY:The first geodetic VLBI field-test of LIFT: a 550Km long optical f iber link for remote antenna synchronization DTSTART;VALUE=DATE-TIME:20160316T083000Z DTEND;VALUE=DATE-TIME:20160316T084500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4624@events.saip.org.za DESCRIPTION:Speakers: Matteo Stagni (IRA - INAF)\nWe present the first fie ld-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 a ntenna participated to the Eur137 experiment carried out in September 201 5\, in tag along mode\, using\, as reference systems\, both the local H ma ser and a remote H maser hosted at the INRIM labs in Turin\, 550km far fro m Medicina. In order to assess the quality of the remote clock\, the obser ved sources were split in two sets\, each one has been observed with the a ssociated H maser (local or remote). A system to switch automatically betw een the two references was integrated in the antenna field system. The obs ervations were correlated in Bonn and preliminary results are encouraging since fringes have been detected with both time references along all the 2 4 hours of the session. The experimental set-up\, the results and the pers pectives for future radio astronomical and geodetic experiments will be pr esented.\n\nhttps://events.saip.org.za/event/56/contributions/4624/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4624/ END:VEVENT BEGIN:VEVENT SUMMARY:ivg::ASCOT: The Development of a new VLBI Software Package DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4627@events.saip.org.za DESCRIPTION:Speakers: Thomas Artz (Institute of Geodesy and Geoinformation \, University of Bonn)\nAlthough several fully developed VLBI software pac kages exist already\, the VLBI group of the Institute of Geodesy and Geoin formations of Bonn University (ivg) started implementing a new analysis to olbox. The main reason is the need for a flexible environment\, which allo ws for straightforward implementations of new scientific and software-rela ted ideas for VLBI data analysis. Furthermore\, we wanted to be able to co ntrol and understand the whole processing chain and\, last but not least\, the developments\, which have been performed in Bonn in recent years\, sh ould be accumulated under a unified software installation.\n\nThe software is implemented in C++ and should finally be able to perform schedules of VLBI sessions\, simulation of VLBI observations as well as geodetic data a nalysis and intra-technique combination. Thus\, it is named: Analysis\, Sc heduling and Combination Toolbox of the Institute of Geodesy and Geoinform ations VLBI group (ivg::ASCOT). Currently\, we are able to perform single- session data analysis in line with the IERS2010 Conventions\, at a stage w here the ambiguities have been resolved. The VGOS-DB data format is used a s input. Furthermore\, global solutions to derive celestial and terrestria l reference frames can be performed on the normal equation level. This can be done based on our single session analysis as well as with SINEX input from other analysis centers. Intra-technique combinations of several solut ions complete the initial functionality of the software package. In this p aper\, we present the modelling of our toolbox as well as some key ideas o f our processing and some first results.\n\nhttps://events.saip.org.za/eve nt/56/contributions/4627/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4627/ END:VEVENT BEGIN:VEVENT SUMMARY:DOR Local-correlation Delay Model Calculation Experiment in CE-3 M ission DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4628@events.saip.org.za DESCRIPTION:Speakers: Yidan Huang (Shanghai Astronomical Observatory)\nThe beacon of CE-3 satellite have several tones for communication and VLBI tr acking. In order to improve data transferring and processing efficiency\, we tried the local-correlation method which was different from the one use d in CE-3 project. The Time delay model used in local-correlation experime nt also differed from normal time delay model. The result shows that there are a few dozen meters of discrepancy between orbit determination result and reference orbit. The equivalent delay difference is less than 1 ns.\n\ nhttps://events.saip.org.za/event/56/contributions/4628/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4628/ END:VEVENT BEGIN:VEVENT SUMMARY:Application and development of VieVS at BACC DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4629@events.saip.org.za DESCRIPTION:Speakers: Johannes Boehm (Technische Universität Wien)\nBACC( Beijing Aerospace Control Center)\, as the command center for the Chinese space program\, got access to VieVS in 2011. Since 2013\, IVS VLBI data ha s been downloaded and analyzed automatically with VieVS at BACC and the ge odetic products will be provided firstly in the presentation. VieVS was al so used to estimate the coordinates of new Chinese VLBI telescopes with do mestic VLBI network in the past two years\, the preliminary results will b e presented secondly. Furthermore\, Chinese lander on the moon has been ob served by IVS VLBI telescopes with success already and the APOD (Atmospher ic density detection and Precise Orbit Determination) satellite provides g reat possibility since it carries dual-frequency GNSS (GPS/BD) receiver\, SLR reflector and S/X band VLBI beacon. VieVS was developed at BACC to mee t the requirements of satellite observations. Lastly EOP prediction has be en interpolated to VieVS and the comparisons of EOP prediction will also b een presented.\n\nhttps://events.saip.org.za/event/56/contributions/4629/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4629/ END:VEVENT BEGIN:VEVENT SUMMARY:ICRF sources: How good is the 'deep' southern sky DTSTART;VALUE=DATE-TIME:20160317T091500Z DTEND;VALUE=DATE-TIME:20160317T093000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4630@events.saip.org.za DESCRIPTION:Speakers: Sayan Basu (University of South Africa and Hartebees thoek Radio Astronomy Observatory\, South Africa)\nThe International Celes tial Reference Frame (ICRF) are constructed using catalogs of extragalacti c radio source (mainly quasars) positions measured at 2.3 and 8.4 GHz with the Very Long Baseline Interferometry (VLBI) technique. Most extragalacti c radio sources exhibit spatially extended structures on milliarcsecond an d sub-milliarcsecond scales which are variable in both time and frequency . These extended structures may contribute significant errors in the VLBI measurements that will introduce uncertainty in the source position measur ements. Therefore\, in order to define and maintain the celestial referenc e frame with the highest accuracy\, efforts are required to map sources an d to study their suitability as reference frame source on VLBI scales. \n We will present multi-epoch imaging results of the ICRF sources in the sou thern sky from the Celestial Reference Frame Deep South (CRDS) observing c ampaign from the IVS. Source morphology as well as source quality aspects will be discussed in the presentation which will give a better understand ing of source behavior at 2.3 and 8.4 GHz observing frequencies with the V LBI technique.\n\nhttps://events.saip.org.za/event/56/contributions/4630/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4630/ END:VEVENT BEGIN:VEVENT SUMMARY:VieVS 2.3 - status of the Vienna VLBI Software and plans for the f uture DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4631@events.saip.org.za DESCRIPTION:Speakers: Johannes Böhm (Technische Universität Wien)\nThe V ienna VLBI Software (VieVS) is a VLBI analysis software developed and main tained at Technische Universität Wien (TU Wien) since 2008 with contribut ions 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 t he geodetic community. Written in a modular structure in Matlab\, VieVS of fers easy access to the source code and the possibility to adapt the progr ams for particular purposes.\nThe new version 2.3\, released in December 2 015\, includes several new parameters to be estimated in the global soluti on\, such as tidal ERP variation coefficients. The graphical user interfac e was slightly modified for an improved user functionality and\, e.g.\, th e possibility of deriving baseline length repeatabilities. The scheduling of satellite observations was refined\, the simulator newly includes the e ffect of source structure which can also be corrected for in the analysis. \nThis poster gives an overview of all VLBI-related activities in Vienna a nd provides an outlook to future plans concerning the Vienna VLBI Software .\n\nhttps://events.saip.org.za/event/56/contributions/4631/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4631/ END:VEVENT BEGIN:VEVENT SUMMARY:Vienna contribution to ITRF2014 DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4632@events.saip.org.za DESCRIPTION:Speakers: Johannes Boehm (Technische Universität Wien)\nThe n ext realisation of the International Terrestrial Reference System\, the IT RF2014\, is currently in preparation or under evaluation\, respectively. T he VLBI input to ITRF2014 is provided by the International VLBI Service fo r Geodesy and Astrometry (IVS) and consists of a combination of all analys is center contributions. One of these single solutions is contributed by t he Vienna special analysis center of the Department of Geodesy and Geoinfo rmation at TU Wien. In this presentation we describe the characteristics o f the Vienna contribution (calculated using the Vienna VLBI Software VieVS ) to ITRF2014 or VTRF2014\, respectively. We give a documentation of the i ncluded sessions and stations as well as some statistical information whic h show the performance of the Vienna contribution compared to the other co ntributions to the IVS combination. In addition to that\, a single solutio n TRF\, VieTRF2014\, which is based on the Vienna input to ITRF2014\, is p resented and compared to previous TRF solutions.\n\nhttps://events.saip.or g.za/event/56/contributions/4632/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4632/ END:VEVENT BEGIN:VEVENT SUMMARY:The XKa Celestial Reference Frame: Assessing Accuracy DTSTART;VALUE=DATE-TIME:20160317T081500Z DTEND;VALUE=DATE-TIME:20160317T083000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4633@events.saip.org.za DESCRIPTION:Speakers: Christopher Jacobs (JPL/NASA)\nObservations at X/Ka- band are motivated by their ability to access more compact source morpholo gy and reduced core shift relative to observations at the historically st andard S/X-band. In addition\, the factor of four increase in interferomet er resolution at Ka-band should resolve out some wide binary black holes w hich are a topic of concern \nfor AGN centroid stability.\n\nGiven these m otivations\, an X/Ka-band (8.4/32 GHz) celestial reference frame has been constructed using a combined NASA and ESA Deep Space Network.  In 124 ob serving sessions we detected 673 sources covering the full 24 hours of ri ght ascension and the full range of declinations. The resulting XKa median precision is now better than the ICRF-2 precision thereby raising the que stion of which frame is more accurate. \n\nComparison of over 500 X/Ka sou rces in common with the S/X-band (2.3/8.4 GHz) ICRF2 produced wRMS agreem ent of about 200 microasec. There is evidence for systematic errors above the 100 microasec level. Known errors include limited SNR\, lack of phase calibration\, troposphere mismodelling\, and terrestrial frame distortion s. Actions are underway to reduce all of these errors. In particular\, a collaboration between NASA and the ESA deep space antenna in Malargüe\,  Argentina is quickly reducing weaknesses in the southern hemisphere. By l ooking at the best observed sources\, we probe the accuracy limits of curr ent celestial frames in an effort to understand the advantages of each fra me.\n\nhttps://events.saip.org.za/event/56/contributions/4633/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4633/ END:VEVENT BEGIN:VEVENT SUMMARY:Progress on the United Nations Global Geospatial Information Manag ement initiative on the Global Geodetic Reference Frame and the Norwegian Mapping Authority's core station project at 79°\; North DTSTART;VALUE=DATE-TIME:20160314T131000Z DTEND;VALUE=DATE-TIME:20160314T132500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4634@events.saip.org.za DESCRIPTION:Speakers: Per Erik Opseth (Norwegian Mapping Authority)\nFebru ary 26th 2015 the United Nations General assembly adopted the resolution o n 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 geo desy\, Norway is building a core station at Ny-Ålesund\, Spitsbergen. Pre sently the station buildings and fundaments are finished and waiting for t he new twin VLBI telescopes to be installed.\n\nhttps://events.saip.org.za /event/56/contributions/4634/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4634/ END:VEVENT BEGIN:VEVENT SUMMARY:Hard- and software tools for the education of Geodetic VLBI DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4635@events.saip.org.za DESCRIPTION:Speakers: Thomas Hobiger (Chalmers / Onsala Space Observatory) \nOnsala Space Observatory hosts two 2.3 m radio telescopes called SALSA ( "Such a lovely small antenna") which are utilised to bring front-line inte ractive astronomy to the classroom. Until now SALSA has been used for astr onomical educational purposes solely\, in particular demonstrating the con cept of single dish measurements. However\, it is possible to combine both SALSAs to an interferometer by making use of hardware which has been deve loped for software-defined radio. In doing so\, one can utilise the SALSA antenna pair as a student demonstrator for geodetic Very Long Baseline Int erferometry. We will discuss the COTS hardware components that are necessa ry to turn the SALSA installation into an interferometer. Moreover\, we wi ll show how a simple correlator has been used to detect fringes and provid e single-band delays. Such delays were then processed with our analysis so ftware c5++. We are going to discuss how it is possible to mimic the compl ete processing chain of geodetic VLBI and how this can be used for trainin g of students and other interested parties.\n\nhttps://events.saip.org.za/ event/56/contributions/4635/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4635/ END:VEVENT BEGIN:VEVENT SUMMARY:Transition to the vgosDb data format. DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4636@events.saip.org.za DESCRIPTION:Speakers: John Gipson (NVI Inc/GSFC NASA)\nThe IVS Working Gro up 4 developed the new format to store and exchange data obtained from geo detic VLBI observations. The new data format\, vgosDb\, will replace exist ing Mk4 databases this year. At the GSFC NASA we developed software that w ill implement vgosDb format and will be used routinely to convert correlat or output to the new data storage format. On this poster we present the vg osDb capable utilities that will replace the legacy software and our plans for switching to vgosDb format in the routine VLBI data analysis.\n\nhttp s://events.saip.org.za/event/56/contributions/4636/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4636/ END:VEVENT BEGIN:VEVENT SUMMARY:Estimating the Celestial Reference Frame via Intra-Technique Combi nation DTSTART;VALUE=DATE-TIME:20160317T073000Z DTEND;VALUE=DATE-TIME:20160317T074500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4637@events.saip.org.za DESCRIPTION:Speakers: Andreas Iddink (Institute of Geodesy and Geoinformat ion\, University of Bonn)\nOne of the primary goals of VLBI is the determi nation of a CRF. Currently the third realization of the internationally ad opted CRF\, the ICRF3\, is under preparation. In this process\, various op timizations are planned to realize a CRF which does not only benefit from the increased number of observations. For instance\, various campaigns hav e been performed to sample the southern hemisphere with a better density. Furthermore\, the VLBI Calibrator Surveys have been redone. Further optimi zations of the ICRF3 with respect to the prior versions will be obtained o n the analysis side. The new ICRF will benefit also from an intra-techniqu e combination as it is also done for the TRF. Following IUGG Resolution No . 3 (2011) this approach can then easily be extended to a consistent estim ation of CRF\, TRF and the EOPs\, based on the observations of different g eodetic space techniques.\n\nHere\, we aim at estimating an optimized CRF by means of an intra-technique combination. The solutions are based on the input to the official combined product of the International VLBI Service for Geodesy and Astrometry (IVS)\, also providing the radio source paramet ers. We discuss the differences in the setup between the classical TRF-EOP combination and an extended CRF-TRF-EOP combination. Furthermore\, we inv estigate the differences between the combined CRF and the CRFs for the ind ividual ACs. Finally\, the impact on the TRF and the EOPs are analyzed to demonstrate the benefits of our enhanced combination procedure.\n\nhttps:/ /events.saip.org.za/event/56/contributions/4637/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4637/ END:VEVENT BEGIN:VEVENT SUMMARY:Implementation of the VGOS Trials DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4638@events.saip.org.za DESCRIPTION:Speakers: Dirk Behrend (NVI\, Inc.)\nIn February 2014\, the VG OS Project Executive Group (VPEG) presented the\nso-called VGOS Observing Plan\, which outlined possible steps on how to go from initial VGOS broadb and tests to intermediate observing scenarios to the fully operational VGO S system. The document introduced VGOS trial campaigns as the initial mean s to accustom the VGOS stations as well as the subsequent component types to the VGOS processing load: scheduling\, data taking\, data transport\, c orrelation\, and analysis. Three different trial campaigns of 6-8 weeks ea ch were envisioned. The Coordinating Center in conjunction with the Observ ing Program Committee (OPC) was tasked with their implementation. In this presentation we will discuss the progress made on implementing the trial c ampaigns.\n\nhttps://events.saip.org.za/event/56/contributions/4638/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4638/ END:VEVENT BEGIN:VEVENT SUMMARY:New DiFX sofware correlator cluster at Bonn DTSTART;VALUE=DATE-TIME:20160316T073000Z DTEND;VALUE=DATE-TIME:20160316T074500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4639@events.saip.org.za DESCRIPTION:Speakers: Arno Mueskens (IGG Uni Bonn)\nWe present the status of the Bonn Correlator Center (2015/2016)\nfor astronomical and geodetic c orrelation. The correlator\ncenter is being operated jointly by the Max Pl anck Institute for Radio\nAstronomy (MPIfR) in Bonn\, the Federal Agency f or\nCartography and Geodesy (BKG) in Frankfurt with support from the\nInst itute of Geodesy and Geoinformation (IGG) in Bonn for more than 20\nyears. \nWe will give a brief summary of the first experience with correlating on our new DiFX correlator cluster\, which was planned to be compatible with the VGSO requirements. \nWe will also report on new features implemented for instance to handle Mark 6 recordings and some benchmarking of the corr elation of VGOS observations\, and on planned further software improvement s.\n\nhttps://events.saip.org.za/event/56/contributions/4639/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4639/ END:VEVENT BEGIN:VEVENT SUMMARY:The IVS Contribution to JTRF2014 DTSTART;VALUE=DATE-TIME:20160316T120000Z DTEND;VALUE=DATE-TIME:20160316T121500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4640@events.saip.org.za DESCRIPTION:Speakers: Richard Gross (Jet Propulsion Laboratory)\nKALREF\, JPL's KALman filter and smoother for REference Frames\, has been used to p roduce JTRF2014\, a combined terrestrial reference frame determined from t he input SINEX files submitted by the IVS\, IGS\, ILRS\, and IDS for ITRF2 014. Using a Kalman filter and smoother allows the reference frame to be d etermined sequentially as a time series. Incorporating process noise\, det ermined from geophysical fluid loading models\, allows the observed statio n positions to be smoothed between discontinuities caused by earthquakes a nd equipment changes. Non-linear and non-seasonal changes in station posit ions\, such as postseismic displacements\, are automatically included in t he smoothed time series. The creation of JTRF2014 will be discussed with a n emphasis on the contribution that the VLBI observations made to it.\n\nh ttps://events.saip.org.za/event/56/contributions/4640/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4640/ END:VEVENT BEGIN:VEVENT SUMMARY:First 2 Gbps observations between KVAZAR VGOS antennas and Yebes R AEGE antenna DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4641@events.saip.org.za DESCRIPTION:Speakers: Pablo de Vicente (Observatorio de Yebes (IGN))\nA se ries of joint test observations using three 13-m VGOS antennas were carrie d on between September and November\, 2015. These were include 256 Mbps ex periments as well as first 2 Gbps observations. Different working setups o f DBBC were tested at Yebes\, data recorded\, and transferred to IAA Corre lator Center. Combined correlation of mixed bandwidth data from KVAZAR ant ennas and Yebes were performed with DiFX 2.4.1 and some results were obtai ned.\n\nhttps://events.saip.org.za/event/56/contributions/4641/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4641/ END:VEVENT BEGIN:VEVENT SUMMARY:Selecting sources that define a stable celestial reference frame w ith the Allan variance DTSTART;VALUE=DATE-TIME:20160317T074500Z DTEND;VALUE=DATE-TIME:20160317T080000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4642@events.saip.org.za DESCRIPTION:Speakers: Karine Le Bail (NVI\, Inc.)\nICRF2 was adopted by th e IAU in 2009 and was based on the position of 3414 radio sources determin ed by VLBI. Discussions on the next realization of the ICRF (ICRF3) have b een underway within the IAU and IVS since 2012. VLBI has made significant advances since ICRF2.\nFrom the latest GSFC solution\, we extract a set of sources that defines a stable celestial reference frame\, as shown by M. Feissel-Vernier 2003 (A&A) using tools such as the Allan variance and the drift of the position time series. This method also allows us to highlight a set of the least "stable" sources that may need special handling.\n\nht tps://events.saip.org.za/event/56/contributions/4642/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4642/ END:VEVENT BEGIN:VEVENT SUMMARY:Prototyping automation and dynamic observing with the AuScope arra y DTSTART;VALUE=DATE-TIME:20160315T074500Z DTEND;VALUE=DATE-TIME:20160315T080000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4643@events.saip.org.za DESCRIPTION:Speakers: Jim Lovell (University of Tasmania)\nThe continuous observing mode envisioned for the new array of VGOS stations would benefit greatly from a high level of automation\, from scheduling through to anal ysis. The centrally-operated AuScope VLBI array of three 12m antennas in A ustralia is serving as a testbed for these automation techniques. Here we describe the challenges we are addressing\, how we are using simulations t o undertand where the most benificial improvements can be obtained (in dyn amic scheduling for example) and present the progress we have already made .\n\nhttps://events.saip.org.za/event/56/contributions/4643/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4643/ END:VEVENT BEGIN:VEVENT SUMMARY:Connected-element interferometry and error analysis of Beidou GEO navigation satellites DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4644@events.saip.org.za DESCRIPTION:Speakers: Fengchun Shu (Shanghai Astronomical Observatory)\nUs ing the same frequency standard\, a high-precision phase delay can be obta ined in a connected element interferometry (CEI) system. Beidou GEO naviga tion satellite C02 is tracked from a CEI observations\, where the CEI of t he two stations at hangtiancheng and shahe linked by a phase stabilization system is built by Beijing Aerospace Control Center (BACC). And Beidou GE O navigation satellite C03 is applied as calibration to conduct a differen tial measurement. After introducing group-delay-aided phase delay\, the me asure noise of the interferometry delay is about 9.4ps (root mean square o f the linear fitting residuals in each 300 seconds). Following a different ial observation as "2 hours calibration-13 hours tracking -2 hours calibra tion"\, the accuracy of the interferometry delay for C02 is better than 0. 4ns. Results show that using a GEO satellite with high-accuracy ephemeris as the calibration\, a high-accuracy interferometry can be achieved for th e target satellite using small aperture antennas.\n\nhttps://events.saip.o rg.za/event/56/contributions/4644/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4644/ END:VEVENT BEGIN:VEVENT SUMMARY:First Local Ties from Data of the Wettzell Triple Radiotelescope A rray DTSTART;VALUE=DATE-TIME:20160315T092500Z DTEND;VALUE=DATE-TIME:20160315T094000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4645@events.saip.org.za DESCRIPTION:Speakers: Torben Schüler (Geodetic Observatory Wettzell - BKG )\nThe Geodetic Observatory Wettzell features a 20 m radiotelescope (RTW) as well as two new 13.2 m TWIN telescopes. Whilst RTW performs routine ope rations since 1984\, the first of the TWIN telescopes\, TTW1\, has entered its productive phase in mid 2014\, and TTW2 has just been equipped with a n Elevenfeed broadband receiving system.\n\nThe triple telescope array at Wettzell establishes a geodetic very short baseline interferometry network . Local correlation yields group delay observations for baseline estimatio n from VLBI data alone without any immediate augmentation by terrestrial m easurements. Apart from relative positioning of the telescopes\, these are versatile capabilities for an end-to-end quality control of the VLBI data .\n\nResults from local VLBI data analysis will be portrayed in this contr ibution and compared to the latest local ties from precision terrestrial s urveying. Moreover\, monitoring results of the TTW2 reference point will b e presented and an initial concept for continuous surveillance of the TWIN reference points is discussed.\n\nhttps://events.saip.org.za/event/56/con tributions/4645/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4645/ END:VEVENT BEGIN:VEVENT SUMMARY:On the impact of different mapping functions on geodetic and tropo spheric products from VLBI data analysis DTSTART;VALUE=DATE-TIME:20160317T103000Z DTEND;VALUE=DATE-TIME:20160317T104500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4646@events.saip.org.za DESCRIPTION:Speakers: Kyriakos Balidakis (Technische Universität Berlin\, Institute of Geodesy and Geoinformation Science\, Berlin\, Germany)\nDue to the highly volatile character of the neutral atmosphere\, the modeling of the related propagation delay is challenging. This poses the most promi nent limitation in the precision and accuracy of the parameters estimated in very long baseline interferometry (VLBI) data analysis. Hence\, it is o f paramount importance that all parameters involved in the process to desc ribe the atmosphere induced delay effects such as mapping functions or gra dients are rigorously accounted for.\nIn this work\, we assess the impact of different mapping functions (MFs) in the analysis of the 24-hour VLBI s essions from 2002 onwards. Besides the original Vienna mapping functions ( VMF1)\, which are based on data from ECMWF operational analysis\, we apply MFs based on this concept but utilizing data from ray tracing in CMC's GD PS (UNB-VMF1). In addition to these we test the concept of advanced mappin g using ECMWF's ERA-Interim reanalysis based on rigorous ray-tracing appro ach. For the parameter estimation we use the VieVS@GFZ software applying t he classical Gauß-Markov model. \nThe purpose of this study is twofold. W e investigate the effect of these analysis options on the baseline length repeatability as well as on the time series of station\, source coordinate s and Earth orientation parameters. As far as the tropospheric products ar e concerned\, estimated zenith wet delays and linear horizontal gradients are compared with the ray traced ones from the aforementioned models.\n\nh ttps://events.saip.org.za/event/56/contributions/4646/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4646/ END:VEVENT BEGIN:VEVENT SUMMARY:INVITED TALK: An Overview of the Japanese GALA-V Wideband V LBI System DTSTART;VALUE=DATE-TIME:20160314T074000Z DTEND;VALUE=DATE-TIME:20160314T080500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4647@events.saip.org.za DESCRIPTION:Speakers: Mamoru Sekido (National Institute of Information and Communications Technology)\nWe are developing a new broadband VLBI system \, named GALA-V with aim of frequency comparison between atomic time stand ards 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 c arry out broadband observation with originally developed two types of prot otype broadband feeds named IGUANA-H and NINJA. Two ways of data acquisiti on modes\; broad channel mode and narrow channel mode\, are employed in th e project. Narrow channel mode acquires multiple channels of 32MHz bandwid th\, and this mode is compatible with the observation mode developed by MI T Haystack as the ‘NASA proof of Concept’ (PoC) system. Broad channel mode acquires four channels of 1 GHz bandwidth signal. RF Direct sampling technique is applied in this mode as a new approach for broadband observat ion by using high speed sampler K6/GALAS. This technique has several advan tages in precision delay derivation by broadband bandwidth synthesis. \nI shioka 13m VGOS station has constructed by GSI in Japan\, and the first br oadband observation over 8 GHz bandwidth was successfully performed in ear ly 2015 on Kashima 34m - Ishioka 13m baseline. We have achieved super broa dband bandwidth synthesis over 8GHz bandwidth for the first time in the wo rld. The theoretical delay precision has reached about 30 femto seconds in this experiment. This presentation will report about recent progress of t he broadband GALA-V developments.\n\nhttps://events.saip.org.za/event/56/c ontributions/4647/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4647/ END:VEVENT BEGIN:VEVENT SUMMARY:Current Status of Ishioka VGOS antenna DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4648@events.saip.org.za DESCRIPTION:Speakers: Ryoji Kawabata (Geospatial Information Authority of Japan)\nThe Geospatial Information Authority of Japan (GSI) is constructin g 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 carr ied out some broadband experiments collaborating with the National Institu te of Information and Communications Technology (NICT). The paper reports current situation of Ishioka VGOS antenna including recent geodetic result of VLBI observation.\n\nhttps://events.saip.org.za/event/56/contributions /4648/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4648/ END:VEVENT BEGIN:VEVENT SUMMARY:Activities of Sejong station and toward the GGOS DTSTART;VALUE=DATE-TIME:20160315T094000Z DTEND;VALUE=DATE-TIME:20160315T095500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4649@events.saip.org.za DESCRIPTION:Speakers: Sang Oh YI (NGII(National Geographic Information Ins titutue))\nThe 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 by KASI(Korea Astronomy & Space Sc ience Institute) at the SGOC site\, current progress of construction KVNG( Korea VLBI Network for Geodesy) and development of wide-band feed horn for VGOS.\n\nhttps://events.saip.org.za/event/56/contributions/4649/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4649/ END:VEVENT BEGIN:VEVENT SUMMARY:Status and first results from the VGOS-compatible antenna Ws with an Elevenfeed at Wettzell DTSTART;VALUE=DATE-TIME:20160314T103000Z DTEND;VALUE=DATE-TIME:20160314T104500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4650@events.saip.org.za DESCRIPTION:Speakers: Gerhard Kronschnabl (Geodetic Observatory Wettzell)\ nThe 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 ba nds 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 broadband development and the recording systems installed at the Wettzell antenna Ws.\n\nhttps://events.saip.org.za/event /56/contributions/4650/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4650/ END:VEVENT BEGIN:VEVENT SUMMARY:Preparations for a new VGOS radio telescope at HartRAO DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4651@events.saip.org.za DESCRIPTION:Speakers: Ludwig Combrinck (HartRAO)\nVery long baseline inter ferometry (VLBI) is used in geodesy to determine a telescope’s position relative to the galactic centre. A modern\, fast slewing radio telescope m easuring approximately 13 metres in diameter have been chosen to be used i n the VLBI Global Observing System (VGOS)\, which will help improve the ac curacy across global baselines from around 1 cm down to 1 mm. In 2014 Hart RAO started the process of obtaining the new radio telescope which will be used within the VGOS network. Specifying the telescope requirements\, Rad io Frequency Interference (RFI) measurements\, core drilling and logging\, and an Environmental Impact Assessment (EIA) are part of the prerequisite actions that need to take place before construction can commence.\n\nhttp s://events.saip.org.za/event/56/contributions/4651/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4651/ END:VEVENT BEGIN:VEVENT SUMMARY:Current Status of Shanghai VLBI Correlator DTSTART;VALUE=DATE-TIME:20160316T080000Z DTEND;VALUE=DATE-TIME:20160316T081500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4652@events.saip.org.za DESCRIPTION:Speakers: Wu Jiang (SHAO\,CAS)\nShanghai Astronomical Observat ory 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 s essions including CRF\, AOV\, and APSG series began from the ealy 2015.Som e X/Ka fringe search experiments were conducted with Tianma 65-m radio tel escope in order to check its performance. In addition to the IVS observati ons\, the correlator is also dedicated to astrophysical and astrometric ob servations with Chinese VLBI network\, the east Asian VLBI network and som e international joint VLBI observations. Meanwhile\, comparisons to the do mestic software correlator and the SFXC correlator are to be made with DiF X. Shanghai correlator is also planning a more powerful platform for the f uture correlation tasks.\n\nhttps://events.saip.org.za/event/56/contributi ons/4652/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4652/ END:VEVENT BEGIN:VEVENT SUMMARY:Update on the Spanish-Portuguese RAEGE project DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4653@events.saip.org.za DESCRIPTION:Speakers: Pablo de Vicente (Observatorio de Yebes (IGN))\nAn u pdate of the deployment and activities at the Spanish/Portuguese RAEGE pro ject (“Atlantic Network of Geodynamical and Space Stations”) is presen ted. Regular observations with Yebes radio telescope are ongoing. Commissi oning of the radio telescope at Santa Maria is advanced\, and site works f or a new station in Tenerife (Canary Islands) have started. Technological developments on receivers for VGOS are progressing at Yebes laboratories\, as well as works on local-ties.\n\nhttps://events.saip.org.za/event/56/co ntributions/4653/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4653/ END:VEVENT BEGIN:VEVENT SUMMARY:The progress of Seshan VGOS station construction DTSTART;VALUE=DATE-TIME:20160314T093000Z DTEND;VALUE=DATE-TIME:20160314T094500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4654@events.saip.org.za DESCRIPTION:Speakers: Guangli Wang (Shanghai Astronomical Observatory)\nTh e 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 o f reference point variation is planing to install. And it locates in the y ard of Tianma 65m radio telescope. Its recent progress will be introduced in this report.\n\nhttps://events.saip.org.za/event/56/contributions/4654/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4654/ END:VEVENT BEGIN:VEVENT SUMMARY:VLBI Delay Reduced from S/C Observation and its Calibration in Cha ng’E Mission DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4657@events.saip.org.za DESCRIPTION:Speakers: Guangli Wang (Shanghai Astronomical Observatory)\nVL BI technique was used in China’s Lunar Exploration Project Since the Cha ng’E-1 launched in the year of 2007\, after then VLBI was played an impo rtant 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 r adio telescopes. Up to now it still works in the traditional astronomy-com patible S/X station systems \, both quasar and S/C are observed in the sa me Frequency setup. In CE-1 & CE-2 the quasar and S/C switching rules are 15min quasar and 45min S/C\, in CE-3 and thereafter are <5min switching.\n \nhttps://events.saip.org.za/event/56/contributions/4657/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4657/ END:VEVENT BEGIN:VEVENT SUMMARY:On the impact of inhomogeneities in meteorological data on VLBI da ta analysis DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4658@events.saip.org.za DESCRIPTION:Speakers: Kyriakos Balidakis (Technische Universität Berlin\, Institute of Geodesy and Geoinformation Science\, Berlin\, Germany)\nIn t his study\, the issue of the quality of meteorological data employed for V LBI data analysis is addressed. Traditionally\, ambient barometric pressur e and temperature values are used to model the hydrostatic component of th e neutral atmospheric propagation delay and the thermal deformation of ant ennas\, in VLBI data analysis. Unlike the other microwave-based space geod etic techniques currently contributing to the TRF\, where the necessary me teorological data are customarily acquired by either empirical or numerica l weather models\, VLBI analysis has the advantage that the aforementioned nuisance effects can be potentially eliminated more effective employing i n situ meteorological data. Nevertheless\, there are cases where erroneous meteorological records yield unacceptable products which have a dubious t raceability. For instance\, if the recorded pressure series at a certain s ite has a significant positive bias with respect to the actual one\, negat ive zenith wet delays will indicate a serious problem. Should the bias be anything but like this\, its detection will be challenging and it will con taminate the geodetic products of the site and potentially at other sites participating in the same session. In the long term\, such biases will aff ect the scale of the estimated TRF.\nWe establishe a service for the onlin e detection and correction of inhomogeneities in recorded meteorological d ata at the VLBI sites. Employing the homogenized data set\, the “IVS Rap id Tropospheric Combination Center” is re-launched providing zenith tota l and wet delays\, as well as linear horizontal gradients.\n\nhttps://even ts.saip.org.za/event/56/contributions/4658/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4658/ END:VEVENT BEGIN:VEVENT SUMMARY:A Technical Overview of the EVN DTSTART;VALUE=DATE-TIME:20160316T071500Z DTEND;VALUE=DATE-TIME:20160316T073000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4659@events.saip.org.za DESCRIPTION:Speakers: Pablo de Vicente (Observatorio de Yebes (IGN))\nAs c hair of the Technical and Operations Group (TOG) of the European VLBI Netw ork (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 schedul ing process together with fringe tests\, network monitor experiments\, sta ndard observations\, e-VLBI observations and target of opportunity observa tions will be described. The EVN signed a MoU with JIVE and as result acti vities from both sides are deeply interleaved. I will present some of thes e activities with relevant impact in the EVN. I will also describe the cal ibration control process. Finally technical developments in the last year\ , including 2 Gbps recording in DDC mode\, 2 Gbps recording in VDIF format supported by the FS for Mark5C\, Mark6 and Flexbuff and the works to get PFB mode will also be presented together with the tests performed. These d evelopments are the result of collaboration works from different parties i n the EVN and also NVI Inc with with which the EVN signed a contract.\n\nh ttps://events.saip.org.za/event/56/contributions/4659/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4659/ END:VEVENT BEGIN:VEVENT SUMMARY:INVITED POSTER: APOD mission status and observe APOD by VLB I DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4660@events.saip.org.za DESCRIPTION:Speakers: Guangli Wang (Shanghai Astronomical Observatory)\nOn Sept. 20\, 2015\, the Chinese CZ-6 test rocket was launched successfully from TaiYuan Satellite Launch Center\, and 20 satellites was sent simultan eously into a circular\, near-polar and 520 Km altitude orbit. Among thes e 20 satellites\, four CubSats\, named with APOD (Atmospheric density dete ction and Precise Orbit Determination)\, are projected for atmospheric den sity in-situ detection and derivation via precise orbit. The APOD satellit es\, manufactured by DFH Co.\, carries a number of instruments including d ensity detector\, dual-frequency GNSS (GPS/BD) receiver\, SLR reflector an d S/X band VLBI beacon. The mission aims to detect atmospheric density bel ow 520 Km. The ground segment is run by BACC for payload operation as well as science data receiving\, processing\, archiving and distribution. Curr ently\, one of the APOD satellites and payload validation had finished\, a nd the preliminary resultsare presented as follows. The precision of orbit determination is about 10cm by both overlap method and by compared with S LR observation\, and the derived atmospheric density from this precise orb it determination matches well with in-situ detection. \n\nSince three spac e geodetic techniques (i.e. GNSS\, SLR\, and VLBI) are co-located on APOD satellite\, the observations can be used for combination and validation in order to detect the systematic differences. Furthermore the observations of APOD satellite by VLBI radio telescope scan be used in an ideal fashion to link the dynamical reference frames of the satellite with terrestrial and\, most importantly\, to the celestial reference frame as defined by th e positions of quasars. From a VLBI observational point of view\, APOD sat ellites rather challenging since mutual visibility depends on the altitude of APOD satellite and the separation of the radio telescopes. And the APO D satellite travel through the field of view very fast. The possibility of observing APOD satellite by IVS VLBI radio telescopes will be analyzed in the presentation\, considering continental-size VLBI observing networks a nd the small telescopes with sufficient speed.\n\nhttps://events.saip.org. za/event/56/contributions/4660/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4660/ END:VEVENT BEGIN:VEVENT SUMMARY:The effects of quasar variability on astrometry DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4661@events.saip.org.za DESCRIPTION:Speakers: Shabala Stanislav (University of Tasmania)\nRadio so urces 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 o ften varies on timescales of months to years as the black hole at the cent re of the quasar accretes new material and ejects components of radio-emit ting plasma. These components expand adiabatically as they move away from the compact core\, and eventually disappear. In this way\, the structure a nd flux density of quasars are related.\n\nWe present an analysis of nine variable quasars frequently observed in global geodetic VLBI programs. We find a clear anti-correlation between source flux density and structure in dex\, in the sense that the brightest sources are also the most compact. T his anti-correlation is stronger on the rising side of the flare\, consist ent with astrophysical expectations. Consistent with previous findings\, w e show that bright\, compact quasars also have more repeatable astrometric positions. We suggest that flux density time series may be a useful addit ional piece of information used in selecting quasars for geodetic VLBI obs ervations.\n\nhttps://events.saip.org.za/event/56/contributions/4661/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4661/ END:VEVENT BEGIN:VEVENT SUMMARY:The Italian VLBI network: first results and future perspectives DTSTART;VALUE=DATE-TIME:20160316T070000Z DTEND;VALUE=DATE-TIME:20160316T071500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4669@events.saip.org.za DESCRIPTION:Speakers: Matteo Stagni (IRA - INAF)\nA first 24-h Italian VLB I 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 prom ising result\, we have planned new observations in 2016\, involving the th ree Italian geodetic antennas\, that should be the beginning of a possible routine activity\, creating a data set that can be combined with GNSS obs ervations to contribute to the National Geodetic Reference Datum. Particul ar care should be taken in the scheduling of the new experiments in order to optimize the number of the usable observations. These observations can be used to study and plan future experiments in which the time and frequen cy standards can be given by an optical fiber link\, so having a common cl ock at different VLBI stations.\n\nhttps://events.saip.org.za/event/56/con tributions/4669/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4669/ END:VEVENT BEGIN:VEVENT SUMMARY:Observing with sibling and twin telescopes DTSTART;VALUE=DATE-TIME:20160315T073000Z DTEND;VALUE=DATE-TIME:20160315T074500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4662@events.saip.org.za DESCRIPTION:Speakers: Lucia Plank (University of Tasmania)\nWith the trans ition 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 VG OS antennas. \nThe co-location of two antennas offers new possibilities in both operation and analysis. The immediate question for observing with a sibling/twin telescope is the applied observing strategy and its realisati on in the scheduling software.\nIn this contribution we report about our e fforts implementing new scheduling modes for sibling and twin telescopes i n the Vienna VLBI Software. On the example of the sibling telescope in Hob art\, several types of sessions will be discussed: scheduling redundant ob servations observing in identical scans\, improved troposphere solution th rough observations in different directions\, improved antenna sensitivity through adding the legacy antenna for observations to weak sources\, or se ssions dedicated to determine the local baseline.\nResults from sibling ex periments\, applying new analysis strategies combining common parameters\, will further demonstrate the potential of twin telescopes for VGOS.\n\nht tps://events.saip.org.za/event/56/contributions/4662/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4662/ END:VEVENT BEGIN:VEVENT SUMMARY:Improvement of the IVS-INT01 Sessions DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4663@events.saip.org.za DESCRIPTION:Speakers: John Gipson (NVI Inc/GSFC NASA)\nAn on-going goal of the GSFC Analysis Center is the improvement of the UT1 formal error obtai ned from the IVS-INT01 sessions\, as well as the improvement of related me trics\, such as robustness against atmospheric turbulence. Improvement can be achieved by improving the scheduling and/or the analysis of these sess ions. Here we report on our latest efforts to improve the performance of the IVS-INT01 sessions.\n\nhttps://events.saip.org.za/event/56/contributio ns/4663/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4663/ END:VEVENT BEGIN:VEVENT SUMMARY:From CONT to VGOS: The Evolution of the CONT Campaigns DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4664@events.saip.org.za DESCRIPTION:Speakers: Cynthia Thomas (NVI\, Inc.)\nContinuous VLBI Campaig ns (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 camp aigns in 1995 and 1996. After a six year hiatus\, CONT campaigns were orga nized approximately every three years from 2002 through 2014. In this pres entation we primarily focus on the cornerstones of each CONT campaign. Spe cifically\, we review the developments in networks\, scheduling techniques \, recording media\, correlation\, and other resources used. A timeline of the history of the CONTs and the goals for future campaigns will be prese nted. The CONTs used a significant amount of IVS resources to produce a la rge volume of high quality data and demonstrated the advantages of continu ous observing which will soon be realized with VGOS.\n\nhttps://events.sai p.org.za/event/56/contributions/4664/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4664/ END:VEVENT BEGIN:VEVENT SUMMARY:On your Marks ... Flex\, Buff and VGOS\, partly even in real-time DTSTART;VALUE=DATE-TIME:20160314T123000Z DTEND;VALUE=DATE-TIME:20160314T124500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4665@events.saip.org.za DESCRIPTION:Speakers: harro verkouter (Joint Institute for VLBI ERIC\, Dwi ngeloo)\nModern\, VGOS and general purpose radio-astronomical digital back ends (DBEs)\, will produce enormous amounts of data\, posing some challen ges for the recorders. Fortunately\, the availability of ever faster digit al hardware has also meant that capturing these large data streams on - re latively speaking - general purpose hardware has become quite feasible.\n\ nCurrently there are two models of ethernet packet recorders in use: MIT H aystack's Mark6 and the FlexBuff\, developed in the European VLBI Network (EVN). As the hardware has become more and more commercial-off-the-shelf ( COTS) so has grown the importance of software support\; in fact\, these ne wer recorders are full software recorders.\n\nAs such the usability and pe rformance of such a recorder is completely defined by the functionality of the software running on it. In this talk I would like to introduce the ca pabilities of EVN's software jive5ab on this class of recorders and what e xtra benefits it may have for dealing with recorded ethernet data.\n\nBesi des these mundane recording aspects\, I would like to present\, on behalf of Stuart Weston (Warkworth\, New Zealand) and Simone Bernhart (IGG Bonn)\ , an application of the features of the jive5ab recording software for rea l-time recording of IVS R1 sessions.\n\nIn this test the scans were record ed on Warkworth's Mark5B+ but also\, in parallel and in real-time\, at the cluster in Bonn. This has proven to work and provides a measurable increa se in turn-around time for correlation with a minimum of hassle if more st ations [w/c]ould do this.\n\nhttps://events.saip.org.za/event/56/contribut ions/4665/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4665/ END:VEVENT BEGIN:VEVENT SUMMARY:IVS Retreat 2015 DTSTART;VALUE=DATE-TIME:20160314T080500Z DTEND;VALUE=DATE-TIME:20160314T082000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4666@events.saip.org.za DESCRIPTION:Speakers: Axel Nothnagel (Institute of Geodesy and Geoinformat ion\, University of Bonn)\nOn October 7 and 8\, 2015\, the IVS Directing B oard held an IVS Retreat at the Dominion Radio Astrophysical Observatory\, Penticton\, BC\, Canada\, to discuss current implications and future chal lenges of the IVS’s existence and operations. In order to benefit from o utside views\, six external advisors had been invited as well. The group s pent two days discussing correlation\, product lines\, institutional relat ions\, and operations details with concepts for the future. Critical items included the aging of the experienced workforce of the IVS\, the preparat ion of the correlators for the large increase in data throughput for VGOS\ , an emphasis on the service aspect of the IVS\, and the need for increase d public relations work\, among other items. In this presentation\, the ch air of the IVS will inform the participants about the retreat and its cons equences.\n\nhttps://events.saip.org.za/event/56/contributions/4666/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4666/ END:VEVENT BEGIN:VEVENT SUMMARY:BRAND EVN DTSTART;VALUE=DATE-TIME:20160314T082000Z DTEND;VALUE=DATE-TIME:20160314T083500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4667@events.saip.org.za DESCRIPTION:Speakers: Gino Tuccari (INAF-IRA and MPI)\nMulti-band concurre nt observation capability for the frequencies bands commonly\nused in EVN greatly could improve the VLBI scientific opportunities\, even enabling im portant simplification in the radiotelescope operations.\nThe project for a 1.5 - 15.5 GHz fully digital receiver is presented with the\npossible so lutions for a smooth introduction in the different from each other\nEVN ra diotelescopes.\n\nhttps://events.saip.org.za/event/56/contributions/4667/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4667/ END:VEVENT BEGIN:VEVENT SUMMARY:INVITED TALK: Status of the ICRF3 and Gaia activities DTSTART;VALUE=DATE-TIME:20160316T130000Z DTEND;VALUE=DATE-TIME:20160316T132500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4668@events.saip.org.za DESCRIPTION:Speakers: Patrick Charlot (Laboratoire d'Astrophysique de Bord eaux)\nThe ICRF3\, the next realization of the International Celestial Ref erence 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 forthco ming optical reference frame to be built by the Gaia mission and aligned a t best with the ICRF3. The ICRF3 work is carried out by an IAU Working Gro up set up in 2012. While the work so far was primarily focused on increasi ng the pool of observations\, it must now concentrate on the analysis. The Gaia mission is operational since September 2014\, observing 30-40 millio n sources per day. It is performing largely nominally despite a few proble ms which slightly degrade the accuracy. A first release of the Gaia data i s planned for mid-2016 while a second release is expected by mid-2017.\n\n https://events.saip.org.za/event/56/contributions/4668/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4668/ END:VEVENT BEGIN:VEVENT SUMMARY:Application of Kalman filtering for the analysis of Intensive se ssions DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4670@events.saip.org.za DESCRIPTION:Speakers: Tobias Nilsson (GFZ German Research Centre for Geosc iences)\nThe VLBI Intensive sessions are one-hour long\, usually single-ba seline VLBI sessions performed every day in order to estimate UT1-UTC. Due to the small number of observations in these sessions\, the latency betwe en observation and results is relatively short\, normally a few days. Howe ver\, the accuracy of the UT1-UTC estimates is significantly lower than ex pected based on their formal errors. Although the reason for this is not c ompletely understood\, it indicates that the results could get better if i mproved modeling or estimation procedures are applied.\nIn this contributi on\, we analyze the Intensive sessions with the newly developed Kalman fil ter module of our software\, VieVS@GFZ\, and investigate whether results i mprove compared to those obtained when applying the classical least square s method for the data analysis. The accuracy is evaluated by comparing the results for UT1-UTC as well as the tropospheric delays with the estimates from 24-hour VLBI sessions on the same days as the Intensives. We study t he impact of different stochastic modelling of the estimated parameters\, e.g. of the tropospheric delays. Furthermore\, we test whether the results could be improved by including tropospheric parameters estimated from GNS S as additional observations in the Kalman filter.\n\nhttps://events.saip. org.za/event/56/contributions/4670/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4670/ END:VEVENT BEGIN:VEVENT SUMMARY:Images of VLBI calibrators from the BeSSeL survey DTSTART;VALUE=DATE-TIME:20160317T094500Z DTEND;VALUE=DATE-TIME:20160317T100000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4671@events.saip.org.za DESCRIPTION:Speakers: Bo Zhang (Shanghai Astronomical Observatory)\nThe Be SSeL 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 motion s to masers in regions of massive star formation across large portions of the Milky Way. To measure the distances of masers via trigonometric parall axes\, the relative positions between the masers and extragalactic VLBI ca librators are determined with phase-referencing VLBI at different epochs s panning at least 1 year. \n\nThe Masers are usually served as phase refere nce since they are much stronger than the calibrators\, allowing several h ours' integration times for the weak calibrators. In addition\, the calibr ators are often observed though the whole observing program\, providing ex cellent uv-coverage for imaging. From the BeSSeL survey\, there will be ab out ~5000 high quality images of ~ 400 VLBI calibrators distributed near t he Galactic plane. For each calibrator\, there are at least 4 images obtai ned from different epochs spanning at least 1 year. In this talk\, I will introduce the construction of the image database of these calibrators\, an d discuss the potential application on VLBI astrometry using this image da tabase.\n\nhttps://events.saip.org.za/event/56/contributions/4671/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4671/ END:VEVENT BEGIN:VEVENT SUMMARY:Metsähovi Geodetic Fundamental Station in Finland - new VGOS site \, plans\, and current status DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4672@events.saip.org.za DESCRIPTION:Speakers: Nataliya Zubko (Finnish Geospatial Research Institut e)\nThe 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 geo detic stations which is used in maintaining global terrestrial and celesti al reference frames\, computing precise orbits of satellites\, and for geo physical studies. Metsähovi is one of the few geodetic stations that has all major geodetic observing instrumentations co-located. These include sa tellite laser ranging (SLR)\, very long baseline interferometry (VLBI)\, g lobal navigation satellite system (GNSS)\, superconducting and absolute gr avimeters\, and the DORIS beacon. The station has been operational since 1 978\, it contributes several global services of the International Associat ion of Geodesy (IAG)\, and due to its long existence it helps to retain su stainability in the maintenance of global reference frames. \n\nIn the aut umn 2015 FGI obtained financial support to build new VGOS compatible radio telescope. This project is funded by Finnish Ministry of Agriculture and Forestry and the National Land Survey. The site chosen for a new telescope is within 100 m from other facilities of the Metsähovi geodetic station. We aim for a 12-13 m telescope and expect to complete the procurement pro cess during the first half of 2016. The plan is to be operational by the e nd of 2018.\n\nhttps://events.saip.org.za/event/56/contributions/4672/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4672/ END:VEVENT BEGIN:VEVENT SUMMARY:Defining Sources Selection and Celestial Reference Frame Stability DTSTART;VALUE=DATE-TIME:20160317T080000Z DTEND;VALUE=DATE-TIME:20160317T081500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4673@events.saip.org.za DESCRIPTION:Speakers: César GATTANO (SYRTE - Observatoire de Paris)\nIn a previous study\, we characterized radio sources observed by Very Long Bas eline Interferometry by different criteria in both radio and optical domai ns (see the abstract "VLBI sources in optical\nand radio"). On the basis o f the data derived from this study\, we constructed several celestial refe rence frames by choosing a set of defining sources and studied their stabi lity by two ways\, statistically and temporally\, inspired by Lambert [201 3]. In parallel\, a re-analysis of the ICRF2 was made\, in the perspective of ICRF3 (expected date : 2018)\, to estimate its current stability and i f it has changed since 2009\, as it was the case for ICRF1 [ Gontier et al . 2001\, Feissel-Vernier 2003\, Lambert et al. 2008\, Lambert & Gontier 20 09 ] . Finally\, an ambitious goal will be to develop by those works an au tomatic tool that will regularly analyse new VLBI observation sessions and will be able to alert the community on defining sources becoming potentia lly unstable.\n\nhttps://events.saip.org.za/event/56/contributions/4673/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4673/ END:VEVENT BEGIN:VEVENT SUMMARY:Plans and progress of the Vienna Correlator DTSTART;VALUE=DATE-TIME:20160314T134500Z DTEND;VALUE=DATE-TIME:20160314T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4674@events.saip.org.za DESCRIPTION:Speakers: Johannes Boehm (Technische Universität Wien)\nThe V LBI group at Technische Universität Wien (TU Wien) is going to run a VLBI software correlator for scientific purposes. For that reason\, DiFX is in stalled on the Vienna Scientific Cluster 3 (VSC-3) consisting of 2020 node s\, each equipped with 2 processors (Intel Xeon E5-2650v2\, 2.6 GHz\, 8 co res). Of course\, only a fraction of the total number of cores will be ava ilable for VLBI correlation. The VSC-3 is connected to the scientific Geà nt network with 10 Gbps\, thus providing a high bandwidth for downloading data via e-transfer. In this presentation\, we provide information about t he current status of that project and future plans.\n\nhttps://events.saip .org.za/event/56/contributions/4674/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4674/ END:VEVENT BEGIN:VEVENT SUMMARY:Simulations of near real-time EOP estimation from a future VGOS ne twork DTSTART;VALUE=DATE-TIME:20160316T095500Z DTEND;VALUE=DATE-TIME:20160316T101000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4675@events.saip.org.za DESCRIPTION:Speakers: Tobias Nilsson (GFZ German Research Centre for Geosc iences)\nThe 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 observ ation and availability of the results\, like the Earth Orientation Paramet ers (EOP) to less than one day. Ideally\, the results should be available in near real-time. Thus\, every part of the VLBI processing chain\, e.g. o bservation\, data transfer\, correlation\, and data analysis\, needs to be able to operate autonomously in real-time.\nTo meet the challenges that V GOS will put on the data analysis part\, we have implemented a Kalman filt er module in our software\, VieVS@GFZ\, which is able to analyze VLBI data fully automated in near real-time. In this contribution\, we present this module\, in particular the setup for real-time analysis\, and we test its performance through simulation of a real-time estimation scenario from a potential future 30 station VGOS network. We focus on the precision obtain ed for the EOP\, which is the most interesting VLBI product in terms of ne ar real-time availability. Furthermore\, we study how well the Kalman filt er is able to autonomously cope with potential problems in the VLBI data\, such as clock breaks.\n\nhttps://events.saip.org.za/event/56/contribution s/4675/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4675/ END:VEVENT BEGIN:VEVENT SUMMARY:INVITED TALK: IVS contribution to the ITRF2014 DTSTART;VALUE=DATE-TIME:20160316T102500Z DTEND;VALUE=DATE-TIME:20160316T105000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4676@events.saip.org.za DESCRIPTION:Speakers: Sabine Bachmann (BKG)\nGenerating the contribution o f the International VLBI Service for Geodesy and Astrometry (IVS) to the I TRF2014 was the main task of the IVS Combination Center at the Federal Age ncy for Cartography and Geodesy (BKG\, Germany) in 2015. Starting with the ITRF2005\, the IVS contribution to the ITRF is an intra-technique combine d solution using multiple individual contributions from different institut ions.\nFor the ITRF2014 nine international institutions were used for a co mbined solution. The data files contain 24h VLBI sessions from the late 19 70s until the end of 2014 in SINEX file format containing datum free norma l equations with station coordinates and Earth orientation parameters (EOP ). All contributions have to meet the IVS standards for ITRF contribution in order to guarantee a consistent combined solution.\nIn the course of th e generation of the intra-technique combined solution\, station coordinate time series for each station as well as a terrestrial reference frame bas ed on the contributed VLBI data (VTRF) were generated and analyzed.\nThe d ata analysis\, the combination procedure and results of the combined solut ion for station coordinates and EOP will be presented.\n\nhttps://events.s aip.org.za/event/56/contributions/4676/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4676/ END:VEVENT BEGIN:VEVENT SUMMARY:The structure of the radio source 0642+449 detected from CONT14 ob servations DTSTART;VALUE=DATE-TIME:20160317T093000Z DTEND;VALUE=DATE-TIME:20160317T094500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4677@events.saip.org.za DESCRIPTION:Speakers: Minghui XU (Shanghai Astronomical Observatory)\nThe CONT14 campaign features state-of-art VLBI data. Therein\, the radio sourc e 0642+449 was observed with about one thousand observables each day durin g the continuous observing period of fifteen days\, providing tens of thou sands of closure delays\, the sum of the delays around a closed loop of ba selines. The closure delay is independent of the instrumental and propagat ion delays and provides valuable additional information about the source s tructure. An example of the use of this new “observable” for the deter mination of source structure is given for the radio source 0642+449. This source\, as one of the defining sources in the second realization of the I nternational Celestial Reference Frame (ICRF2)\, is found to have two poin t-like components with separation of 425 milliarcseconds in right ascensio n and 47 milliarcseconds in declination. The two components are almost equ ally bright with the flux-density ratio up to 0.92. With the help of recen t space VLBI observations at 1.6 GHz\, the morphology of 0642+449 could be identified to some extent. The closure delays larger than 1 ns are found to be caused by the source structure as well\, demonstrating the structure effect of a source with this simple structure could reach up to tens of n anoseconds\, at least one magnitude larger than expected. We anticipate ou r study to be a starting point for more effective determination of the str ucture effect in VLBI observations without the involvement of radio source images.\n\nhttps://events.saip.org.za/event/56/contributions/4677/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4677/ END:VEVENT BEGIN:VEVENT SUMMARY:Constraining Least Squares VLBI Solutions DTSTART;VALUE=DATE-TIME:20160316T091000Z DTEND;VALUE=DATE-TIME:20160316T092500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4678@events.saip.org.za DESCRIPTION:Speakers: Thomas Artz (Institute of Geodesy and Geoinformation \, University of Bonn)\nIn a traditional least squares adjustment of param eters to the VLBI observation\, typically tropospheric as well as clock pa rameters 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 hou rs\, singularities arise due to unresolvable parameters inside these gaps. This issue as well as the geometric datum deficiency require additional i nformation to determine the VLBI target parameters\, e.g\, Earth orientati on parameters\, as well as the celestial and terrestrial reference frames. For this reason\, it is necessary to constrain the respective parameters in the solution. \n\nIn this paper we analyze the singularities which aris e within the geodetic VLBI data analysis and show the ramifications of tra ditional constraining. Furthermore\, we give suggestions to optimize the l east squares solution with regard to constraining the VLBI solution. The e ffects of various approaches are validated by the analysis of continuous V LBI campaigns.\n\nhttps://events.saip.org.za/event/56/contributions/4678/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4678/ END:VEVENT BEGIN:VEVENT SUMMARY:An Inequality Constrained Least-Squares approach as an alternative estimation procedure for atmospheric parameters from VLBI observations DTSTART;VALUE=DATE-TIME:20160317T101500Z DTEND;VALUE=DATE-TIME:20160317T103000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4679@events.saip.org.za DESCRIPTION:Speakers: Sebastian Halsig (Institute of Geodesy and Geoinform ation\, University of Bonn)\nOn its way through the atmosphere\, the signa ls of space-geodetic techniques\, such as GNSS or VLBI\, are delayed and a ffected 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 techni ques play a crucial role in the understanding of the Earth's atmosphere\, because atmospheric parameters can be linked to the water vapor content in the atmosphere.\n\nIn the VLBI data analysis\, the tropospheric delay is usually taken into account by applying an adequate model for the hydrostat ic component and by additionally estimating zenith wet delays for the high ly variable wet component. Unfortunately\, the standard Least-Squares appr oach sometimes leads to negative estimates\, which would be equivalent to negative water vapor in the atmosphere and does of course not reflect the meteorological and physical conditions in a plausible way.\n\nTo cope with this phenomenon\, we introduce an Inequality Constrained Least-Squares (I CLS) method from the field of convex optimization and use inequality const raints to force the tropospheric parameters to be non-negative allowing fo r a more realistic tropospheric parameter estimation in a meteorological s ense. The impact of the ICLS approach will be validated with regard to sta tion positions. Since deficiencies in the a priori hydrostatic modeling ar e almost fully compensated by the tropospheric estimates\, the ICLS approa ch urgently requires suitable a priori hydrostatic delays. Thus\, we prese nt strategies to deal with missing or incorrect a priori model data.\n\nht tps://events.saip.org.za/event/56/contributions/4679/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4679/ END:VEVENT BEGIN:VEVENT SUMMARY:Application of Kalman filtering for the determination of a VLBI te rrestrial reference frame DTSTART;VALUE=DATE-TIME:20160316T121500Z DTEND;VALUE=DATE-TIME:20160316T123000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4680@events.saip.org.za DESCRIPTION:Speakers: Benedikt Soja (GFZ German Research Centre for Geosci ences)\nTerrestrial reference frames (TRF) of high quality are indispensab le for many geoscientific and geodetic applications including very long ba seline interferometry (VLBI) data analysis. While secular station coordina te changes\, e.g. due to tectonic plate motion\, can be well represented b y a linear model\, current accuracy requirements also demand modeling of n on-linear signals such as surface deformations due to mass loading or post -seismic deformations. The ITRF2014\, for instance\, includes coefficients for exponential and logarithmic functions after major earthquakes. Anothe r approach\, used for the determination of JTRF2014\, is the application o f Kalman filtering that allows post-seismic displacements to be accounted for in a non-parametric manner.\n\nIn this paper\, we portray a TRF soluti on solely based on VLBI data\, employing Kalman filtering and smoothing fo r the computation of session-wise coordinates of more than hundred VLBI ra dio telescopes over more than 30 years. By using a random walk process\, n on-linear coordinate changes are modeled stochastically. The noise model i s derived from loading deformation time series that are not included in th e model for the station motion (i.e.\, non-tidal atmosphere\, non-tidal oc ean\, and continental water storage loading). This stochastic model alone is not able to adapt to the large coordinate variations that can happen af ter major earthquakes. Therefore\, we additionally increase the process no ise in the periods following earthquakes based on the amplitude of the est imated coordinate jumps\, introducing the epochs of the seismic events as prior information.\n\nWe compare our Kalman filtered and smoothed VLBI-TRF to a classical least squares VLBI solution calculated by the VieVS@GFZ so ftware\, based on linear segments between episodic events. Additionally\, multi-technique TRF\, such as the ITRF2014 and JTRF2014\, are included in the comparisons\, especially for assessing the different approaches of mod eling post-seismic deformations.\n\nhttps://events.saip.org.za/event/56/co ntributions/4680/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4680/ END:VEVENT BEGIN:VEVENT SUMMARY:Results from the VLBI Analysis Software Comparison Campaign 2015 DTSTART;VALUE=DATE-TIME:20160316T094000Z DTEND;VALUE=DATE-TIME:20160316T095500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4681@events.saip.org.za DESCRIPTION:Speakers: Grzegorz Klopotek (Chalmers University of Technology )\nThe IERS Conventions contain recommendations\, definitions and models f or space geodetic techniques including geodetic VLBI. In practice\, differ ent analysis software packages follow different estimation methods\, use a variety of different correction models and sometimes adhere to convention s that might not be the latest. This may lead to differences in the result s that should not appear among the software packages dealing with the same observational data-set. Consistency of geodetic VLBI analysis is especial ly important for the VLBI Global Observing System (VGOS)\, for which we ne ed station position and velocity accuracies of 1 mm and 0.1 mm per year\, respectively.\nThe aim of the VLBI Analysis Software Comparison Campaign 2 015 (VASCC2015) was to compare different VLBI analysis software packages o n the basis of computed theoretical delays. Two networks\, one in the nort hern and one in the southern hemisphere\, were scheduled in a way so that in each network a single source could be tracked continuously. In total fi fteen consecutive 24 hour sessions with one minute observation resolution formed the base of this comparison campaign. More than eight research grou ps and institutes participated in this project\, which allowed us to compa re software packages that are used in operational VLBI analysis as well as those being currently under development. \nWe are going to present the fi rst results and the outcomes of this project and we show how well the indi vidual software packages agree. We will discuss discrepancies between anal ysis software packages and reveal where those differences are coming from. Moreover\, we are going to evaluate whether these discrepancies are small enough to be neglected for reaching the VGOS goals.\n\nhttps://events.sai p.org.za/event/56/contributions/4681/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4681/ END:VEVENT BEGIN:VEVENT SUMMARY:Robust ambiguity estimation for automated analysis of Intensive se ssions DTSTART;VALUE=DATE-TIME:20160316T092500Z DTEND;VALUE=DATE-TIME:20160316T094000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4682@events.saip.org.za DESCRIPTION:Speakers: Niko Kareinen (Chalmers University of Technology)\nR obust and automatic estimation of ambiguities is one of the main requireme nts 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 ar e accessible. Version-1 corresponds to correlation output meaning the ambi guity elimination and the ionosphere calibration need to be performed prio r to parameter estimation. In total we use 1778 databases in this study. T he analysis is done in two steps. First the session is processed in automa tic mode to resolve the ambiguities and estimate the ionospheric delays. T hen\, we estimate UT1-UTC using the ionosphere-free databases. In standard c5++ both steps use the well-known least-squares optimization (L2-norm mi nimization) to fit the model to the observations. We introduce the L1-norm minimization into the first step and then estimate UT1-UTC using the leas t-squares method. The results are compared with databases analysed using l east-squares in both steps. The performance differences are assessed by in vestigating the session fit and the respective UT1-UTC estimates. Further details can be found in [1].\n\n[1] Kareinen et al. (2015)\, Robust ambigu ity estimation for automated analysis of Intensive sessions\, manuscript s ubmitted to Computers & Geosciences.\n\nhttps://events.saip.org.za/event/5 6/contributions/4682/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4682/ END:VEVENT BEGIN:VEVENT SUMMARY:Real-time e-VLBI in the EVN and software correlation at JIVE DTSTART;VALUE=DATE-TIME:20160316T074500Z DTEND;VALUE=DATE-TIME:20160316T080000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4683@events.saip.org.za DESCRIPTION:Speakers: Bob Campbell (JIVE)\nReal-time e-VLBI continues to f orm an integral element of the European VLBI Network (EVN)\, accounting fo r about a quarter of all EVN hours and providing unique rapid-response cap abilities to transient events as well as the opportunity for higher-cadenc e observations compared to the standard EVN sessions that fall three times per year. The EVN software correlator at JIVE (SFXC) can currently proce ss real-time correlation for a 14-station array at 1 Gbps with cross-polar izations. Tests show that 8-9 stations at 2 Gbps can also be sustained. \ n\n The classes of e-EVN proposals has grown to include two new types of triggered observations. "Generic triggers" allow a set of potential targe ts that can not be defined explicitly at proposal time\, which opens e-EVN observations to newly discovered transient sources. "Automatic triggers" can receive and adjudicate trigger requests without human intervention (e .g.\, by a program listening for specified VO events)\, and can similarly create and distribute an appropriately modified schedule to override the currently running observations (for stations permitting such remote interv entions). This can provide significantly faster response -- down to 10 mi nutes\, as compared to the 29 hr for traditional triggers. Running jive5a b at the correlator and the stations enables simultaneous real-time e-VLBI correlation and recording (at the correlator and/or at the stations). Th is permits\, among other applications\, commensal searches for transients via analysis of the real-time autocorrelations\, the result of which could trigger a wide-field correlation of the baselines for the corresponding t ime-range\, detached from the on-going real-time correlation. \n\n SFXC h as processed all EVN disk-based observations correlated at JIVE since the May/June 2012 session\, and all e-EVN observations since December 2012. I t removes the physical limitations to the number of stations\, the channel & total bit-rates\, and the number of frequency points. It also applies a purely station-based fringe rotation\, decouples the correlation and del ay-tracking FFT sizes\, and permits choice of the spectral-windowing funct ion. It can correlate observations containing a mixed number of channels\ , mixed channel bandwidths\, and mis-matched side-bands -- accelerating de velopments in various digital back-ends has led to this being a quite rout ine situation. SFXC opens up new astronomical areas for correlation at JI VE via pulsar gating/binning (including coherent de-dispersion)\, multiple phase-center output within a wider field\, spectral zooming\, space VLBI (comprising both antennas in orbit such as RadioAstron\, and near-field ta rgets in the solar-system)\, and a phased-up mode. Each of these has been exploited by proposal-driven user experiments over the past couple years. \n\nhttps://events.saip.org.za/event/56/contributions/4683/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4683/ END:VEVENT BEGIN:VEVENT SUMMARY:Plan for a VLBI antenna in Tahiti from 2018 DTSTART;VALUE=DATE-TIME:20160314T083500Z DTEND;VALUE=DATE-TIME:20160314T085000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4684@events.saip.org.za DESCRIPTION:Speakers: richard Biancale (CNES/GRGS)\nIt is known that the V LBI Global Observing System (VGOS) network suffers from a lack of implemen tation in the South Pacific area. It is why GRGS was considering setting u p a VLBI antenna in Tahiti in cooperation with NASA.\nThere is an existing geodetic observatory (OGT) in the campus of the French Polynesian Univers ity (UPF) which was created in 1998 in a tripartite cooperation between UP F\, NASA and CNES. It gathers several geodetic instruments such as the NAS A’s MOBLAS-8 station\, a DORIS master beacon and several GNSS receivers. But there is not enough room to install a VLBI antenna\, moreover in an e nvironment surrounded by many buildings or houses.\nThat is why we explore d other hosting possibilities for a NASA's VLBI2010 antenna and other new geodetic instruments (SLR-NG\, Regina GNSS\, DORIS). Finally\, we could fi nd an adequate ground on the site of the Tahiti Nui Telecom (TNT) company. The project was submitted then to the French involved organisms: CNES\, I NSU-CNRS\, OCA… and to NASA for further implementing studies.\nWe propos e to describe the state-of-the-art of this project for a possible realizat ion from 2018 in addition to the core space geodetic network. Some simulat ion results will be presented as well in support to this project.\n\nhttps ://events.saip.org.za/event/56/contributions/4684/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4684/ END:VEVENT BEGIN:VEVENT SUMMARY:Accurate spacecraft positioning by VLBI imaging DTSTART;VALUE=DATE-TIME:20160317T143000Z DTEND;VALUE=DATE-TIME:20160317T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4685@events.saip.org.za DESCRIPTION:Speakers: Weimin Zheng (Shanghai Astronomical Observatory\,CAS )\nVLBI is a radio astronomy tool with very high space angle resolution an d Chinese VLBI Network has played a important roles in the Chang’E serie s lunar mission. In the upcoming Chinese lunar and deep space missions\, h igher angular position ability is needed. For these reasons\, we carried o ut research on accurate spacecraft positioning and conducted several space vehicles phase-referencing positioning experiments using the Chinese VLBI network and other VLBI antennas. The near-field target uvw prediction met hod is adopted. This paper shows the VLBI spacecraft imaging position expe riment results of several ChangE lunar probes\, the Mars Express probe and the Rosetta probe. The results validate VLBI with the mill-arcsecond leve l position ability for deep space probes.\n\nhttps://events.saip.org.za/ev ent/56/contributions/4685/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4685/ END:VEVENT BEGIN:VEVENT SUMMARY:INVITED TALK: Delay & Phase Calibration in VGOS Post-proces sing DTSTART;VALUE=DATE-TIME:20160314T124500Z DTEND;VALUE=DATE-TIME:20160314T131000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4686@events.saip.org.za DESCRIPTION:Speakers: Roger Cappallo (MIT Haystack Observatory)\nNow 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 o rder to create a high-quality geodetic observable one wants to minimize th e sensitivity of group delay to instrumental parameters that may change ov er time\, while at the same time maximizing the amount of information that is extracted. This talk will address a number of topics relevant to those goals\, such as matching of delays in polarization products and receiving bands\, and coherent phasing of the four polarization products. Software that automates the somewhat tedious determination of the calibration param eters will be described. The accurate removal of the effect of the ionosph ere is central to a precision observable\, and our procedures and experien ce in doing so will be discussed.\n\nhttps://events.saip.org.za/event/56/c ontributions/4686/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4686/ END:VEVENT BEGIN:VEVENT SUMMARY:Combination of the two radio space geodetic techniques with VieVS during CONT14 DTSTART;VALUE=DATE-TIME:20160316T124500Z DTEND;VALUE=DATE-TIME:20160316T130000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4687@events.saip.org.za DESCRIPTION:Speakers: Younghee Kwak (Technische Universität Wien)\nUnlike CONT11\, CONT14 does not have official information on common frequency st andards for co-location sites. Nevertheless\, according to Kwak et al. (20 15)\, we have a possibility to find the co-located sites\, which used the same clocks\, through comparing clock rates from single technique solution s. Moreover\, CONT14 includes co-located VLBI radio telescopes\, i.e. HOBA RT26 and HOBART12. Therefore\, it is a good test bed to develop the analys is strategy for future twin/sibling telescopes.\nIn this study\, we comput e GNSS single differences between the ranges from two stations to a satell ite\, using phase measurements with most of the errors corrected by the c5 ++ software. We estimate station coordinates and site common parameters\, i.e. zenith wet delays\, troposphere gradients and clock parameters\, with the Vienna VLBI Software. Common clock parameters are limited to the site s that are sharing the same frequency standard during CONT14. Local tie ve ctors are introduced as fictitious observations for co-located instruments \, GNSS-VLBI and even VLBI-VLBI\, i.e. at Hobart. In this presentation\, w e show the comparison results between the combination solutions and the si ngle technique solutions in terms of station position repeatability during 15 days.\n\nhttps://events.saip.org.za/event/56/contributions/4687/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4687/ END:VEVENT BEGIN:VEVENT SUMMARY:VGOS observations with GGAO12M\, Westford\, and the new Kokee 12m antenna DTSTART;VALUE=DATE-TIME:20160314T094500Z DTEND;VALUE=DATE-TIME:20160314T100000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4688@events.saip.org.za DESCRIPTION:Speakers: Arthur Niell (MIT Haystack Observatory)\nThe GGAO 12 m and Westford 18m antennas are instrumented with the broadband signal cha in to provide VGOS capability. These antennas have been making VGOS geode tic observations for more than a year. Approximately seventeen one- to tw enty-four-hour VGOS sessions were conducted in 2015 to develop and test ma ny of the procedures needed for an operational program\, including schedul ing\, unattended observing\, correlation\, and preliminary data analysis t hrough geodetic estimation. Currently\, after the creation of a schedule\ , the session can be run unattended following checkout of the antenna sens itivity and pointing. The Field System controls the Backend\, including t he four UpDownConverters (for band frequency selection)\, the four RDBE-G digital backends in polyphase filter bank (PFB) mode\, and the Mark6 recor der. For correlation direct playback from the Mark6 is being tested. The broadband delay observable is derived by combining the four linear polariz ation cross-products in all four RF bands and simultaneously estimating th e phase dispersion due primarily to the ionosphere. With some slight modi fications of the database creation and editing programs it has been possib le to do geodetic analysis of most of the sessions using nuSolve. Prelimi nary analysis of the first eleven sessions gives a weighted RMS deviation of 2 mm from the mean baseline length (600 km) for those one-hour sessions .\n\nThe Kokee 12m VGOS antenna\, designed and manufactured by InterTronic s Solutions\, has been completed\, and the broadband signal chain\, built by Haystack\, will be installed in early 2016. It is expected that Kokee1 2m will be added to the GGAO-Westford observations by February\, and the p rocedures developed for the GGAO-Westford sessions will form the basis for observations with the three-station network.\n\nResults for both the GGAO -Westford series and for observations with all three antennas will be repo rted.\n\nhttps://events.saip.org.za/event/56/contributions/4688/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4688/ END:VEVENT BEGIN:VEVENT SUMMARY:Ultra-rapid earth rotation determination with VLBI during CONT11 a nd CONT14 DTSTART;VALUE=DATE-TIME:20160317T123000Z DTEND;VALUE=DATE-TIME:20160317T124500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4689@events.saip.org.za DESCRIPTION:Speakers: Rüdiger Haas (Chalmers University of Technology)\nI n 2007 the Geospatial Information Authority of Japan (GSI) and the Onsala Space Observatory (OSO) started a collaboration project aiming at determin ing the earth rotation angle\, usually expressed as UT1-UTC\, in near real -time. In the beginning of this project dedicated one hour long one-baseli ne experiments were observed periodically using the VLBI stations Onsala ( Sweden) and Tsukuba (Japan). The strategy is that the observed VLBI data a re sent in real-time via the international optical fibre backbone to the c orrelator at Tsukuba where the data are correlated with a software correla tor and analyzed in near-real time with the c5++ VLBI data analysis softwa re\, thus producing UT1-UTC results with very low latency. The latency bet ween the observation at the stations and the determination of UT1-UTC is o n the order of a few minutes\, thus we can talk about an ultra-rapid deter mination of UT1-UTC. An offline version of this strategy was adopted in 20 09 for the regular VLBI intensive series INT-2\, organized by the Internat ional VLBI Service for Geodesy and Astrometry (IVS)\, that involves Wettze ll (Germany) and Tsukuba. Since March 2010 the INT-2 is using real-time e- transfer\, too\, and since June 2010 also automated analysis. Starting in 2009 the ultra-rapid approach was applied to regular 24 hour long IVS VLBI -sessions that involve Tsukuba and Onsala\, so that ultra-rapid UT1-UTC re sults can be produced already during ongoing VLBI-sessions. This strategy was successfully operated during the 15 days long continuous VLBI campaign s CONT11 and CONT14. In this presentation we give an overview of the ultra -rapid concept\, present the results derived during CONT11 and CONT14\, an d compare these ultra-rapid results to results derived from post-processin g.\n\nhttps://events.saip.org.za/event/56/contributions/4689/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4689/ END:VEVENT BEGIN:VEVENT SUMMARY:Effects on Earth Orientation Parameters caused by different analys is options DTSTART;VALUE=DATE-TIME:20160317T124500Z DTEND;VALUE=DATE-TIME:20160317T130000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4690@events.saip.org.za DESCRIPTION:Speakers: Robert Heinkelmann (GFZ Potsdam)\nThe Earth Orientat ion Parameters (EOP) are arguments of the time-dependent rotation matrices describing the difference in orientation between the Earth crust-fixed re ference system\, ITRS\, and the space-fixed reference system\, ICRS. Very Long Baseline Interferometry (VLBI) is the technique that connects the rea lizations of ITRS and ICRS in terms of orientation directly on the observa tion level. Many applications in spacecraft navigation\, fundamental astro nomy\, astrometry\, and geosciences depend on the provision of the Earth O rientation Parameters (EOP). Currently\, under the IAG/IAU Joint Working G roup on the Theory of Earth Rotation\, activities are supported that foste r the advance on the theory of Earth rotation. Some components of the Eart h rotation\, such as the Free Core Nutation (FCN)\, are not well predictab le but rely entirely on empirical determination through VLBI. In our paper we step-by-step alternate different analysis options\, such as a priori d ata and models\, and quantify the resulting effects on the EOP. Our approa ch is purely empirical: we will alternate certain analysis options and ass ess the differences with respect to the reference solution that adheres to IERS Conventions (2010) and applies the parameterization that was used in our contribution to ITRF2014\, the next realization of the ITRS. For demo nstration we analyze current regular International VLBI Service for Geodes y and Astrometry (IVS) sessions: IVS-R1 and –R4. The IAG flagship compon ent GGOS (Global Geodetic Observing System) aims to realize EOP with an ac curacy of 1 mm\, i.e. about 30 microarcseconds. This accuracy will be used as a threshold to interpret the significance of the effects.\n\nhttps://e vents.saip.org.za/event/56/contributions/4690/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4690/ END:VEVENT BEGIN:VEVENT SUMMARY:Current status of an implementation of a system monitoring for sea mless auxiliary data at the Geodetic Observatory Wettzell DTSTART;VALUE=DATE-TIME:20160315T080000Z DTEND;VALUE=DATE-TIME:20160315T081500Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4691@events.saip.org.za DESCRIPTION:Speakers: Alexander Neidhardt (Technische Universität Münche n\, Geodätisches Observatorium Wettzell)\nA 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 datab ase 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 ant ennas. The presentation demonstrates the implementation and discusses the current possibilities to encourage other antennas to join the auxiliary ar chive.\n\nhttps://events.saip.org.za/event/56/contributions/4691/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4691/ END:VEVENT BEGIN:VEVENT SUMMARY:IVS Combiantion Center at BKG: Options and functions of the revise d website DTSTART;VALUE=DATE-TIME:20160314T150000Z DTEND;VALUE=DATE-TIME:20160314T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T111815Z UID:indico-contribution-56-4692@events.saip.org.za DESCRIPTION:Speakers: Sabine Bachmann (BKG)\nThe International VLBI Servic e for Geodesy and Astrometry (IVS) Combination Center at the Federal Agenc y for Cartography and Geodesy (BKG\, Germany) is responsible for generatin g combined Earth orientation parameter (EOP) products. Additionally\, res ults of combined station coordinates and a terrestrial reference frame bas ed on VLBI observations are generated. For providing information on the co mbination\, the Combination Center maintains the CCIVS website where resul ts\, activities and new products are presented. Due to the implementation of a new content management system\, the website was revised and new funct ions were added. A new search function was realized to find individual ter ms of the page content. A glossary\, a sitemap and simplified standardized contact forms improve and enhance the handling of the website. The new de sign is clear\, color matched and fills up the text content with informati ve graphics and pictures. Information about the results on the IVS contrib ution to the ITRF2014 were introduced and all existing data is regularly u pdated. The website is reachable over the Internet link ccivs.bkg.bund.de or www.ccivs.bkg.bund.de. In the future all users may get in contact with the Combination Center via the simplified contact forms or the new central email address ccivs@bkg.bund.de. The revised website with old and new opt ions\, functions and features is presented.\n\nhttps://events.saip.org.za/ event/56/contributions/4692/ LOCATION: URL:https://events.saip.org.za/event/56/contributions/4692/ END:VEVENT END:VCALENDAR