@article{12792d9fef8a43a780b776fb8029f1f8,
title = "Baseline Vector Repeatability at the Sub-Millimeter Level Enabled by Radio Interferometer Phase Delays of Intra-Site Baselines",
abstract = "We report the results of position ties for short baselines at eight geodetic sites based on phase delays that are extracted from global geodetic very-long-baseline interferometry (VLBI) observations rather than dedicated short-baseline experiments. An analysis of phase delay observables at X band from two antennas at the Geodetic Observatory Wettzell, Germany, extracted from 107 global 24-hr VLBI sessions since 2019 yields weighted root-mean-square scatters about the mean baseline vector of 0.3, 0.3, and 0.8 mm in the east, north, and up directions, respectively. Position ties are also obtained for other short baselines between legacy antennas and nearby, newly built antennas. They are critical for maintaining a consistent continuation of the realization of the terrestrial reference frame, especially when including the new VGOS network. The phase delays of the baseline WETTZ13N–WETTZELL enable an investigation of sources of error at the sub-millimeter level. We found that a systematic variation of larger than 1 mm can be introduced to the Up estimates of this baseline vector when atmospheric delays were estimated. Although the sub-millimeter repeatability has been achieved for the baseline vector WETTZ13N–WETTZELL, we conclude that long term monitoring should be conducted for more short baselines to assess the instrumental effects, in particular the systematic differences between phase delays and group delays, and to find common solutions for reducing them. This will be an important step toward the goal of global geodesy at the 1 mm level.",
keywords = "geodetic VLBI, GGOS, ITRF, phase delays, reference frames, VGOS",
author = "Xu, {Ming H.} and Tuomas Savolainen and Sergei Bolotin and Simone Bernhart and Christian Pl{\"o}tz and R{\"u}diger Haas and Eskil Varenius and Guangli Wang and Jamie McCallum and Robert Heinkelmann and Susanne Lunz and Harald Schuh and Nataliya Zubko and Niko Kareinen",
note = "Funding Information: We would like to thank Arthur Niell very much for the comments during the reviews. The results reported in this paper used the data coordinated by the International VLBI Service (IVS) and its international self‐funded member organizations. We are grateful to the IVS stations at Hartebeesthoek (South Africa Radio Astronomical Observatory), Ishioka (Geospatial Information Authority of Japan), Kokee Park (U.S. Naval Observatory and NASA GSFC, USA), Ny‐{\AA}lesund (Norwegian Mapping Authority, Norway), Onsala (Onsala Space Observatory, Chalmers University of Technology, Sweden), Shanghai (Shanghai Astronomical Observatory, China), Wettzell (Bundesamt f{\"u}r Kartographie und Geod{\"a}sie and Technische Universit{\"a}t M{\"u}nchen, Germany), and Yebes (Instituto Geogr{\'a}fico Nacional, Spain), to the staff at the Bonn Correlator, the Washington Correlator, the Onsala Observatory Correlator, and the MIT Haystack Observatory correlator for performing the correlations and the fringe fitting of the data, to the NASA GSFC VLBI group and the BKG VLBI group for doing the geodetic solutions, and to the IVS Data Centers at BKG (Leipzig, Germany), Observatoire de Paris (France), and NASA CDDIS (Greenbelt, MD, USA) for the central data holdings. This research has made use of the Generic Mapping Tools package, the pgplot library, and the SAO/NASA Astrophysics Data System. The work was supported by the Academy of Finland project No. 315721. Open Access funding enabled and organized by Projekt DEAL. Funding Information: We would like to thank Arthur Niell very much for the comments during the reviews. The results reported in this paper used the data coordinated by the International VLBI Service (IVS) and its international self-funded member organizations. We are grateful to the IVS stations at Hartebeesthoek (South Africa Radio Astronomical Observatory), Ishioka (Geospatial Information Authority of Japan), Kokee Park (U.S. Naval Observatory and NASA GSFC, USA), Ny-{\AA}lesund (Norwegian Mapping Authority, Norway), Onsala (Onsala Space Observatory, Chalmers University of Technology, Sweden), Shanghai (Shanghai Astronomical Observatory, China), Wettzell (Bundesamt f{\"u}r Kartographie und Geod{\"a}sie and Technische Universit{\"a}t M{\"u}nchen, Germany), and Yebes (Instituto Geogr{\'a}fico Nacional, Spain), to the staff at the Bonn Correlator, the Washington Correlator, the Onsala Observatory Correlator, and the MIT Haystack Observatory correlator for performing the correlations and the fringe fitting of the data, to the NASA GSFC VLBI group and the BKG VLBI group for doing the geodetic solutions, and to the IVS Data Centers at BKG (Leipzig, Germany), Observatoire de Paris (France), and NASA CDDIS (Greenbelt, MD, USA) for the central data holdings. This research has made use of the Generic Mapping Tools package, the pgplot library, and the SAO/NASA Astrophysics Data System. The work was supported by the Academy of Finland project No. 315721. Open Access funding enabled and organized by Projekt DEAL. Publisher Copyright: {\textcopyright} 2023. The Authors.",
year = "2023",
month = mar,
doi = "10.1029/2022JB025198",
language = "English",
volume = "128",
journal = "JOURNAL OF GEOPHYSICAL RESEARCH: SOLID EARTH",
issn = "2169-9313",
publisher = "Wiley-Blackwell",
number = "3",
}