Vienna VLBI and Satellite Software (VieVS) for Geodesy and Astrometry

Böhm, Johannes; Böhm, Sigrid; Boisits, Janina; Girdiuk, Anastasiia; Gruber, Jakob; Hellerschmied, Andreas; Krásná, Hana; Landskron, Daniel; Madzak, Matthias; Mayer, David J.; McCallum, Jamie; McCallum, Lucia; Schartner, Matthias; Teke, Kamil

doi:10.1088/1538-3873/aaa22b

Cited by 63 publications

(38 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In total this data set includes about 13 million observations of about 4,500 sources. The VLBI CRF solutions were generated using the Vienna VLBI and Satellite Software (Böhm et al 2018), which is developed by TU Wien. These solutions follow the IERS Conventions 2010 by Petit and Luzum (2010) for reducing the observations and geophysical modeling.…”

Section: Dataandanalysismentioning

confidence: 99%

Comparing Vienna CRF solutions to Gaia-CRF2

Mayer

Boehm

2020

International Association of Geodesy Symposia

Self Cite

View full text Add to dashboard Cite

We are using various models and analysis strategies, such as galactic aberration, ray-tracing etc., to create different Vienna celestial reference frame (CRF) solutions. These solutions are then compared against the Gaia reference frame (Gaia-CRF2). This is done using a degree 2 vector spherical harmonics approach. The estimated parameters are used to investigate the impact of the various analysis methods on the differences between Gaia and the Very Long Baseline Interferometry (VLBI) CRF. We find that correcting for galactic aberration reduces the difference between the Gaia-CRF2 and the VLBI CRF significantly (30 µas in D 2 and 13 µas in D 3 ). Furthermore, we find that using a priori ray-traced tropospheric delays in addition with low absolute constraints on tropospheric gradients reduces the a e 20 parameter by 20 µas. Using these analysis strategies we can explain almost all significant differences between the Gaia-CRF2 and the VLBI CRF. However, the vector spherical harmonic (VSH) parameter a e 20 is still highly significant and can not be explained by modeling and analysis choices from the VLBI technique.

show abstract

Section: Dataandanalysismentioning

confidence: 99%

Comparing Vienna CRF solutions to Gaia-CRF2

Mayer

Boehm

2020

International Association of Geodesy Symposia

Self Cite

View full text Add to dashboard Cite

show abstract

“…Over the last several years, several groups that include WG8 members have made solutions for the secular aberration vector A using Calc/Solve (Ma et al 1990) or VieVS (Böhm et al 2018), where it was not assumed that it was in the Galactic center direction. Table 2 shows the estimates and uncertainties of the secular aberration vector components: Galactic center component A G = A X , the component A Y in the direction of motion around the Galactic center, and the component A Z toward the Galactic pole, and the direction of the vector that was estimated for each solution.…”

Section: Geodetic Vlbi Solutionsmentioning

confidence: 99%

Galactocentric acceleration in VLBI analysis

MacMillan

Fey

Gipson

et al. 2019

A&A

View full text Add to dashboard Cite

Aims. The IVS Working Group on Galactic Aberration (WG8) was established to investigate issues related to incorporating the effect of Galactic aberration in IVS analysis. The circular motion of the solar system barycenter around the Galactic center causes a change in aberration, which in the case of geodetic VLBI observing is over time scales of several decades. One of the specific goals was to recommend a Galactic aberration model to be applied by the IAU ICRF3 working group in the generation of ICRF3 as well as in other IVS analysis. Studies made by working group members have shown that the three-dimensional acceleration vector of the solar system barycenter can be estimated from VLBI delay observations. Methods. Among the working group members, three methods were used to estimate the acceleration vector. One is to directly estimate the acceleration vector as a global parameter. The second is to estimate the acceleration vector from source proper motions determined from estimated source position time series. A third method estimated a global reference frame scale parameter for each source and derived the acceleration vector from these estimates. The acceleration vector estimate consists of a galactocentric component along with the non-galactocentric components. Results. The geodetic reference frame VLBI estimates of the galactocentric aberration constant from the different working group members are in the range 5.1-6.4 µas yr −1 . These estimates are relatively close to independent estimates of 4.8-5.4 µas yr −1 that can be derived from astrometric measurements of proper motions and parallaxes of masers in the Milky Way galaxy. Based on the most recent geodetic VLBI solutions, we find an upper bound of 0.8 µas yr −1 for the non-galactocentric component of the secular aberration. Conclusions. The working group made a recommendation only for the galactocentric component of the observed acceleration vector. For the recommended galactocentric aberration constant, the working group chose a geodetic value to be consistent with geodetic VLBI applications. The recommended value 5.8 µas yr −1 was estimated directly in a global solution that used the ICRF3 solution data set: 1979-May 2018.

show abstract

“…The single session analysis and setting up of the VLBI normal equations are performed with the VLBI module of the Vienna VLBI and Satellite Software VieVS (Böhm et al, 2018). Using vgosDB as input format, we set up single session normal equations for four different networks, for the original XA and XB networks and for the two subnets as depicted in Fig.…”

Section: Preparation Of Vlbi Normal Equationsmentioning

confidence: 99%

Earth rotation variations observed by VLBI and the Wettzell “G” ring laser during the CONT17 campaign

et al. 2019

Self Cite

View full text Add to dashboard Cite

Abstract. The VLBI (Very Long Baseline Interferometry) technique can provide the full set of parameters needed for the transformation between celestial and terrestrial reference frames with high accuracy. Yet it has some limitations regarding temporal resolution and continuity, and the accuracy of the resulting Earth Orientation Parameters (EOP) varies depending on the network geometry. In this work we explore the benefit of combining VLBI observations with the measurements of the large ring laser gyroscope “G” in Wettzell for deriving highly resolved ERP (Earth Rotation Parameters, i.e. polar motion and universal time variations, δUT1). We examine the observations collected by two simultaneously operating VLBI networks during the 15 d of the CONT17 campaign. These two networks, of 14 globally distributed telescopes each, were designed for the estimation of Earth rotation variations, for which reason the resulting hourly ERP are appointed as benchmark in this investigation. To evaluate the advantage of a VLBI and ring laser combined solution, we create degraded versions of the original networks, containing only six stations. The ERP derived from those sparse networks and from the VLBI sparse plus ring laser solutions are then compared in terms of differences to the reference values. It should certainly be considered that these are relative numbers, since they are also determined by the number and selection of the stations remaining in the sparse networks. The root mean square of the difference to the benchmark is reduced by 24 % in case of δUT1 from one network. The polar motion yp component from the same network moves 14 % closer to the reference value due to the inclusion of the ring laser data. The impact on xp and on all ERP from the other network ranges between 2 % and 9 %. The research again confirms the feasibility and also the potential gain of a combined evaluation of VLBI and ring laser observations, but the full capacity of such a sensor fusion will emerge once the ring laser gyroscopes reach a level of accuracy similar to VLBI.

show abstract

Vienna VLBI and Satellite Software (VieVS) for Geodesy and Astrometry

Cited by 63 publications

References 38 publications

Comparing Vienna CRF solutions to Gaia-CRF2

Comparing Vienna CRF solutions to Gaia-CRF2

Galactocentric acceleration in VLBI analysis

Earth rotation variations observed by VLBI and the Wettzell “G” ring laser during the CONT17 campaign

Contact Info

Product

Resources

About