VLBI geodesy: 2 parts-per-billion precision in length determinations for transcontinental baselines

We have used very-long-baseline interferometry (VLBI) to make twenty-two independent measurements, between September 1984 and December 1986, of the length of the 3900-km baseline between the Mojave site in California and the Haystack/Westford site in Massachusetts. These experiments differ from the typical geodetic VLBI experiments in that a large fraction of observations are obtained at elevation angles between 4° and 10°. Data from these low elevation angles allows the vertical coordinate of site position, and hence the baseline length, to be estimated with greater precision. For the sixteen experiments processed thus far, the weighted root-mean-square scatter of the estimates of the baseline length is 8 mm. We discuss these experiments, the processing of the data, and the resulting baseline length estimates.

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A Tri-Band Cooled Receiver for Geodetic VLBI

Sensors ◽

10.3390/s21082662 ◽

2021 ◽

Vol 21 (8) ◽

pp. 2662

Author(s):

José A. López-Pérez ◽

Félix Tercero-Martínez ◽

José M. Serna-Puente ◽

Beatriz Vaquero-Jiménez ◽

María Patino-Esteban ◽

...

Keyword(s):

Very Long Baseline Interferometry ◽

Low Noise ◽

Cryogenic Temperatures ◽

Geospatial Information ◽

Receiver Noise ◽

Geodetic Vlbi ◽

Long Baseline ◽

Front End ◽

X Band ◽

Santa Maria

This paper shows a simultaneous tri-band (S: 2.2–2.7 GHz, X: 7.5–9 GHz and Ka: 28–33 GHz) low-noise cryogenic receiver for geodetic Very Long Baseline Interferometry (geo-VLBI) which has been developed at Yebes Observatory laboratories in Spain. A special feature is that the whole receiver front-end is fully coolable down to cryogenic temperatures to minimize receiver noise. It was installed in the first radio telescope of the Red Atlántica de Estaciones Geodinámicas y Espaciales (RAEGE) project, which is located in Yebes Observatory, in the frame of the VLBI Global Observing System (VGOS). After this, the receiver was borrowed by the Norwegian Mapping Autorithy (NMA) for the commissioning of two VGOS radiotelescopes in Svalbard (Norway). A second identical receiver was built for the Ishioka VGOS station of the Geospatial Information Authority (GSI) of Japan, and a third one for the second RAEGE VGOS station, located in Santa María (Açores Archipelago, Portugal). The average receiver noise temperatures are 21, 23, and 25 Kelvin and the measured antenna efficiencies are 70%, 75%, and 60% in S-band, X-band, and Ka-band, respectively.

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Orbit Determination of Geostationary Earth Orbit Satellite by Transfer with Differenced Ranges between Slave-Slave Stations

Journal of Navigation ◽

10.1017/s0373463313000581 ◽

2013 ◽

Vol 67 (1) ◽

pp. 163-175 ◽

Cited By ~ 3

Author(s):

Cao Fen ◽

Yang XuHai ◽

Su MuDan ◽

Li ZhiGang ◽

Feng ChuGang ◽

...

Keyword(s):

Orbit Determination ◽

Very Long Baseline Interferometry ◽

Baseline Length ◽

Positioning System ◽

Orbit Error ◽

Long Baseline ◽

Data Volume ◽

Clock Offset ◽

Range Observation

In order to more restrict the transverse orbit error, a new method named “differenced ranges between slave stations by transfer”, similar to Very Long Baseline Interferometry (VLBI) observation, has been developed in the Chinese Area Positioning System (CAPS). This method has the number of baselines added, the baseline length increased and the data volume enlarged. In this article, the principle of “differenced ranges between slave stations by transfer” has been described in detail, with the clock offset between slave stations and system error which affects the precision of the differenced ranges observation being discussed. Using this method, the differenced observation of the SINOSAT-1 satellite with C-band between slave stations from 6 to 13 June 2005 was conducted. Then a comparison was made between the accuracy of orbit determination and orbit prediction. A conclusion can be drawn that the combination of pseudo-range receiving the own-station-disseminated signal and the differenced range observation between slave-slave stations has a higher orbit determination and prediction accuracy than using only the former.

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Station Infrastructure Developments of the IVS

10.5194/egusphere-egu2020-12847 ◽

2020 ◽

Author(s):

Dirk Behrend ◽

Axel Nothnagel ◽

Johannes Böhm ◽

Chet Ruszczyk ◽

Pedro Elosegui

Keyword(s):

Very Long Baseline Interferometry ◽

Global Network ◽

Radio Telescopes ◽

Geodetic Vlbi ◽

The Past ◽

Long Baseline ◽

Aging Infrastructure ◽

Recent Developments ◽

International Vlbi Service ◽

Vlbi Data

<p>The International VLBI Service for Geodesy and Astrometry (IVS) is a globally operating service that coordinates and performs Very Long Baseline Interferometry (VLBI) activities through its constituent components. The VLBI activities are associated with the creation, provision, dissemination, and archiving of relevant VLBI data and products. The operational station network of the IVS currently consists of about 40 radio telescopes worldwide, subsets of which participate in regular 24-hour and 1-hour observing sessions. This legacy S/X observing network dates back in large part to the 1970s and 1980s. Because of highly demanding new scientific requirements such as sea-level change but also due to the aging infrastructure, the larger IVS community planned and started to implement a new VLBI system called VGOS (VLBI Global Observing System) at existing and new sites over the past several years. In 2020, a fledgling network of 8 VGOS stations started to observe in operational IVS sessions. We anticipate that the VGOS network will grow over the next couple of years to a global network of 25 stations and will eventually replace the legacy S/X system as the IVS production system. We will provide an overview of the recent developments and anticipated evolution of the geodetic VLBI station infrastructure.</p>

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Experience from geodetic very long baseline interferometry observations at Onsala using a digital backend

Journal of Geodetic Science ◽

10.1515/jogs-2015-0004 ◽

2015 ◽

Vol 5 (1) ◽

Author(s):

N. Kareinen ◽

R. Haas

Keyword(s):

Very Long Baseline Interferometry ◽

Recording System ◽

Data Sets ◽

Space Observatory ◽

Geodetic Vlbi ◽

Long Baseline ◽

Vlbi Observations ◽

Onsala Space Observatory ◽

Base Band ◽

Raw Observations

AbstractThe Onsala Space Observatory has installed a modern digital backend for geodetic and astronomical Very Long Baseline Interferometry (VLBI). This system consists of a Digital Base-Band Converter (DBBC) and a Mark 5B+ recorder. From 2011 until late 2014 this new system was run for geodetic VLBI observations in parallel with the old system consisting of a Mark 4 rack and Mark 5A recording system. Several of these observed sessions were correlated at the correlator in Bonn including both data sets. We present results from the analysis and comparison of these sessions. Both the original observed delays and corresponding geodetic parameters are compared. No significant differences are detected, for either the raw observations or for the geodetic parameters. This shows that the digital backend can be used operationally for geodetic VLBI observations.

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First Geodetic Observations Using New VLBI Stations ASKAP-29 and WARK12M

Publications of the Astronomical Society of Australia ◽

10.1071/as10048 ◽

2011 ◽

Vol 28 (2) ◽

pp. 107-116 ◽

Cited By ~ 6

Author(s):

Leonid Petrov ◽

Chris Phillips ◽

Tasso Tzioumis ◽

Bruce Stansby ◽

Cormac Reynolds ◽

...

Keyword(s):

New Zealand ◽

Very Long Baseline Interferometry ◽

Vertical Component ◽

Systematic Errors ◽

Horizontal Component ◽

Path Delay ◽

Random Errors ◽

Geodetic Vlbi ◽

The North ◽

Long Baseline

AbstractWe report the results of a successful 7-hour 1.4 GHz Very Long Baseline Interferometry (VLBI) experiment using two new stations, ASKAP-29 located in Western Australia and WARK12M located on the North Island of New Zealand. This was the first geodetic VLBI observing session with the participation of these new stations. We have determined the positions of ASKAP-29 and WARK12M. Random errors on position estimates are 150–200 mm for the vertical component and 40–50 mm for the horizontal component. Systematic errors caused by the unmodeled ionosphere path delay may reach 1.3 m for the vertical component.

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A Tri-band Low-noise Cryogenic Receiver for Geodetic VLBI Observations with VGOS Radio Telescopes

10.20944/preprints201912.0408.v1 ◽

2019 ◽

Author(s):

José A. López-Pérez ◽

Félix Tercero-Martínez ◽

José M. Serna-Puente ◽

Beatriz Vaquero-Jiménez ◽

María Patino-Esteban ◽

...

Keyword(s):

Radio Telescope ◽

Very Long Baseline Interferometry ◽

Low Noise ◽

Radio Telescopes ◽

Geospatial Information ◽

Ka Band ◽

Geodetic Vlbi ◽

Long Baseline ◽

Vlbi Observations ◽

X Band

This paper shows the development of a simultaneous tri-band (S: 2.2 - 2.7 GHz, X: 7.5 - 9 GHz and Ka: 28 - 33 GHz) low-noise cryogenic receiver for geodetic Very Long Baseline Interferometry (geo-VLBI) which has been developed by the technical staff of Yebes Observatory (IGN) laboratories in Spain. The receiver was installed in the first radio telescope of the Red Atlántica de Estaciones Geodinámicas y Espaciales (RAEGE) project, which is located in Yebes Observatory, in the frame of the VLBI Global Observing System (VGOS). After this, the receiver was borrowed by the Norwegian Mapping Autorithy (NMA) for the commissioning of two VGOS radiotelescopes in Svalbard (Norway). A second identical receiver was built for the Ishioka VGOS station of the Geospatial Information Authority (GSI) of Japan, and a third one for the second RAEGE VGOS station, located in Santa María (Açores Archipelago, Portugal). The average receiver noise temperatures are 21, 23 and 25 Kelvin and the measured antenna efficiencies are 70%, 75% and 60% in S-band, X-band and Ka-band, respectively.

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