VLBI-derived troposphere parameters during CONT08

Heinkelmann, Robert; Boehm, J.; Bolotin, S.; Engelhardt, G.; Haas, Rüdiger; Lanotte, R.; MacMillan, D. S.; Negusini, M.; Skurikhina, E.; Titov, Oleg; Schuh, Harald

doi:10.1007/s00190-011-0459-x

Cited by 21 publications

(6 citation statements)

References 18 publications

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“…These estimations correspond very well (better than 1 cm) and are consistent with meteorological models (at the centimeter level). Numerous authors have dealt with this subject: Heinkelmann et al (2011), Behrend et al (2002), Niell et al (2001), etc. Among them, Steigenberger et al (2007) and Teke et al (2013) studied ZTD estimations during CONT02 and during all the CONT campaigns, respectively, on the basis of the data of GNSS, VLBI, DORIS, water vapor radiometers, and meteorological models.…”

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confidence: 99%

Comparison of individual and combined zenith tropospheric delay estimations during CONT08 campaign

Pollet

Coulot

Bock

et al. 2014

J Geod

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CONT campaigns are 2-week campaigns of continuous VLBI observations. The IERS working group on combination at the observation level uses these campaigns to study such combinations. In this work, combinations of DORIS, GPS, SLR, and VLBI technique measurements are studied during CONT08. We present different results concerning the use of common zenith tropospheric delay (ZTD) during the combination. We compare the ZTD obtained separately using each individual technique data processing, the combined ZTD, and the ZTD derived from a meteorological model. This resulted in a high level of consistency between each of these ZTD at a sub-centimeter level, a consistency which especially depends on the number of observations per estimated ZTD and the humidity level in the troposphere. We noted that GPS provides the main information about the combined ZTD, the other techniques providing complementary information when a lack of GPS observations occurs.

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confidence: 99%

Comparison of individual and combined zenith tropospheric delay estimations during CONT08 campaign

Pollet

Coulot

Bock

et al. 2014

J Geod

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“…The formal error is however in general always underestimating the real uncertainty. Heinkelmann et al (2011) addressed this question by comparing the ZWD results from ten different analysis centres and concluded that overall there was an underestimation with approximately a factor of 2. Their results also show that the formal uncertainties of the ZWD from the different centres for the same experiment also vary with a factor of 2, depending on the assumptions made when setting up the analysis.…”

Section: Intermediate Discussionmentioning

confidence: 99%

Water vapour radiometry in geodetic very long baseline interferometry telescopes: assessed through simulations

Forkman

Flygare

Elgered

2021

J Geod

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The accuracy of geodetic Very Long Baseline Interferometry (VLBI) is affected by water vapour in the atmosphere in terms of variations in the signal propagation delay at the different stations. This “wet” delay may be estimated directly from the VLBI data, as well as from independent instruments, such as collocated microwave radiometers. Rather than having stand-alone microwave radiometers we have, through simulations, evaluated the possibility to use radiometric data from the VLBI receiver in the VGOS telescopes at the Onsala Space Observatory. The advantage is that the emission from water vapour, as sensed by the radiometer, originates from the same atmospheric volume that delays the VLBI signal from the extra-galactic object. We use simulations of the sky brightness temperature and the wet delay together with an assumption of a root-mean-square (rms) noise of the receiver of 1 K, and observations evenly spread between elevation angles of 10$$^\circ $$ ∘ –90$$^\circ $$ ∘ . This results in an rms error of the estimated equivalent zenith wet delay of the order of 3 mm for a one frequency algorithm, used under cloud free conditions, and 4 mm for a two frequency algorithm, used during conditions with liquid water clouds. The results exclude rainy conditions when the method does not work. These errors are reduced by a factor of 3 if the receiver error is 0.1 K meaning that the receivers’ measurements of the sky brightness temperature is the main error source. We study the impact of ground-noise pickup by using a model of an existing wideband feed. Taking the algorithm uncertainty and the ground noise pickup into account we conclude that the method presented will be useful as an independent estimate of the wet delay to assess the quality of the wet delays and linear horizontal gradients estimated from the VLBI data themselves.

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“…The ICRF is a catalogue of positions of extragalactic radio sources with the highest precision, which are crucial to many applications. For example, the ICRF provides sources that are observed in the geodetic VLBI observations conducted by the IVS to measure the orientation of Earth in space and station motions (Hellmers et al 2021), which in turn contributes to the realization of the ITRF and allows studies of the motion of the tectonic plates and the interior of the Earth (Carter and Robertson 1993), and measurements of the ionosphere and troposphere which allows for atmospheric studies (Heinkelmann et al 2011). High-accuracy celestial reference frames are also crucial for many other applications such as satellite tracking, orbit determination, and deep-space navigation (Thornton and Border 2000), alignment of the planetary ephemerides (Park et al 2021), studies of special and general relativity (Fomalont et al 2009) such as Galacto-centric acceleration (MacMillan et al 2019), and for phase-referencing observations in astronomy (Beasley and Conway 1995;Rioja and Dodson 2020).…”

Section: Introductionmentioning

confidence: 99%

On more than two decades of Celestial Reference Frame VLBI observations in the deep south: IVS-CRDS (1995–2021)

Weston

Witt

Krásná

et al. 2023

Publ. Astron. Soc. Aust.

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The International VLBI Service for Geodesy & Astrometry (IVS) regularly provides high-quality data to produce Earth Orientation Parameters (EOP), and for the maintenance and realization of the International Terrestrial and Celestial Reference Frames, ITRF and ICRF. The first iteration of the celestial reference frame (CRF) at radio wavelengths, the ICRF1, was adopted by the International Astronomical Union (IAU) in 1997 to replace the FK5 optical frame. Soon after, the IVS began official operations and in 2009 there was a significant increase in data sufficient to warrant a second iteration of the CRF, ICRF2. The most recent ICRF3, was adopted by the IAU in 2018. However, due to the geographic distribution of observing stations being concentrated in the Northern hemisphere, CRFs are generally weaker in the South due to there being fewer Southern Hemisphere observations. To increase the Southern Hemisphere observations, and the density, precision of the sources, a series of deep South observing sessions was initiated in 1995. This initiative in 2004 became the IVS Celestial Reference Frame Deep South (IVS-CRDS) observing program. This paper covers the evolution of the CRDS observing program for the period 1995 to 2021, details the data products and results, and concludes with a summary of upcoming improvements to this ongoing project.

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VLBI-derived troposphere parameters during CONT08

Cited by 21 publications

References 18 publications

Comparison of individual and combined zenith tropospheric delay estimations during CONT08 campaign

Comparison of individual and combined zenith tropospheric delay estimations during CONT08 campaign

Water vapour radiometry in geodetic very long baseline interferometry telescopes: assessed through simulations

On more than two decades of Celestial Reference Frame VLBI observations in the deep south: IVS-CRDS (1995–2021)

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