Short-baseline interferometry local-tie experiments at the Onsala Space Observatory

Haas, Rüdiger; Nilsson, Tobias

doi:10.1007/s00190-021-01509-5

Cited by 12 publications

(23 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These two kinds of broadband observables thus actually refer to different directions, with possibly a large separation on the sky. If the phase observables from VGOS can be used in geodetic solutions, as was recently done for very short baselines (see, e.g., Varenius et al 2021;Niell et al 2021;Xu et al 2021c), the source position differences need to be addressed. Based on Eqs.…”

Section: Differences In Vgos Group Delay and Phase-delay Source Posit...mentioning

confidence: 99%

Impact of the image alignment over frequency for the VLBI Global Observing System

Mei-ling

Savolainen

Anderson

et al. 2022

A&A

View full text Add to dashboard Cite

Aims. The VLBI Global Observing System (VGOS), which is the next generation of geodetic very long baseline interferometry (VLBI), observes simultaneously in four frequency bands in the range 3.0-10.7 GHz (expected to be extended to 14 GHz). Because source structure changes with frequency, we aim to study the source position estimates from the observations of this new VLBI system. Methods. Based on an ideal point source model, simulations are run to determine the relation between the source positions as determined by VGOS observations and the locations of the radio emission in the four bands. Results. We obtained the source positions as determined by VGOS observations as a function of the source positions in the four frequency bands for both group and phase delays. The results reveal that if the location of the radio emission in one band is offset with respect to that in the other bands, the VGOS position estimates can be shifted by a larger amount (up to more than three times that offset), possibly in the opposite direction. Conclusions. The VGOS source positions will be highly variable with time and imprecise as to the locations of the radio emission in the four bands if the effects of source structure are not modeled. The image alignment over frequency is essential for modeling these effects, which is the only way to mitigate the impact of such frequency-dependent radio emission on the resulting VGOS source positions.

show abstract

Section: Differences In Vgos Group Delay and Phase-delay Source Posit...mentioning

confidence: 99%

Impact of the image alignment over frequency for the VLBI Global Observing System

Mei-ling

Savolainen

Anderson

et al. 2022

A&A

View full text Add to dashboard Cite

show abstract

“…The IVS VTRF2020b (BKG 2020) and the ITRF2014 (Altamimi et al 2016) were used as a priori values for the VLBI and GNSS station coordinates, respectively. The VTRF2020b coordinates that were determined through dedicated shortbaseline interferometry campaigns, were used for the VGOS Onsala twin telescopes (Varenius et al 2021). The ICRF3 (Charlot et al 2020) realization of the celestial reference frame and the IERS-14-CO4 series (Bizouard et al 2019) was used as a priori information on source positions and EOP.…”

Section: Analysis Options and Parameterizationmentioning

confidence: 99%

Combining VGOS, legacy S/X and GNSS for the determination of UT1

Diamantidis

Haas

Schartner

et al. 2022

J Geod

Self Cite

View full text Add to dashboard Cite

We perform a combination on the observation level (COL) between VLBI and co-located GNSS in the context of VLBI intensive sessions. Our approach revolves around an estimation procedure which uses 3 h of GNSS data that uniformly encapsulate the 1-h VLBI data, in order to provide consistent troposphere information. We test this approach on both VGOS and Legacy S/X using the VGOS-B and concurrently observed INT1 sessions. The COL strategy is found to increase the precision by 15 % over both session types and leads to an increase of 65 % in the agreement between the sessions when estimating tropospheric gradients every 3 h. A more frequent estimation of the gradients every 1 h, which can be rigorously pursued with the utilization of multi-GNSS, results in a further convergence of the two session types by 30 %. The COL-aided length-of-day (LOD) products also show a 55 % better agreement to external GNSS-derived LOD. In the light of the increasing precision of broadcast GNSS orbits and clocks, this COL strategy can be used to derive rapid UT1-UTC products.

show abstract

“…Varenius et al. ( 2021 ) describe mixed-mode observations between the legacy and the VGOS twin telescopes at the Onsala Space Observatory. Using X-band phase delay observations, they successfully determine the coordinates of the new twin telescopes and investigate other systematic errors.…”

Section: Introductionmentioning

confidence: 99%

“…Mixed-mode observations have also been performed by other groups within the IVS, mainly for the purpose of determining the local tie vectors between existing and new VGOS telescopes. Varenius et al (2021) describe mixedmode observations between the legacy and the VGOS twin telescopes at the Onsala Space Observatory. Using X-band phase delay observations, they successfully determine the coordinates of the new twin telescopes and investigate other systematic errors.…”

Section: Introductionmentioning

confidence: 99%

The Australian mixed-mode observing program

McCallum

Chuan

Krásná

et al. 2022

J Geod

View full text Add to dashboard Cite

Global geodetic VLBI is upgrading to its next-generation observing system, VGOS. This upgrade has turned out to be a process over multiple years, until VGOS reaches its full capabilities with the envisaged continuous observations. Until then, for the Australian stations, the upgrade means ceasing their legacy S/X observations, leaving a large gap in the global network as well as in the station time series. The Australian mixed-mode observing program is a series of sessions where the VGOS stations in Hobart and Katherine observe legacy S/X VLBI together with other stations in the region. This paper describes the technical details of these observations and their processing strategies and discusses their suitability for geodetic results by comparison with those of standard legacy S/X sessions. The presented mixed-mode sessions allow a continuation of the station time series, a benefit for the stations themselves as well as for future realisations of the terrestrial and celestial reference frames. A novel mode of observing is introduced and tested. The results are promising and it is suggested for acceptance into standard legacy S/X IVS observations, overcoming current gaps in the network due to VGOS upgrades and preventing a worsening of global results otherwise.

show abstract

Short-baseline interferometry local-tie experiments at the Onsala Space Observatory

Cited by 12 publications

References 16 publications

Impact of the image alignment over frequency for the VLBI Global Observing System

Impact of the image alignment over frequency for the VLBI Global Observing System

Combining VGOS, legacy S/X and GNSS for the determination of UT1

The Australian mixed-mode observing program

Contact Info

Product

Resources

About