Baseline Vector Repeatability at the Sub-Millimeter Level Enabled by Radio Interferometer Phase Delays of Intra-Site Baselines
Journal article, 2023
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.
GGOS
geodetic VLBI
phase delays
VGOS
reference frames
ITRF
Author
Minghui Xu
German Research Centre for Geosciences (GFZ)
Aalto University
T. Savolainen
Aalto University
S. Bolotin
National Aeronautics and Space Administration (NASA)
Simone Bernhart
Reichert GmbH
C. Plötz
Federal Agency for Cartography and Geodesy (BKG)
Rüdiger Haas
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Eskil Varenius
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Guangli Wang
Chinese Academy of Sciences
J. N. McCallum
University of Tasmania
R. Heinkelmann
German Research Centre for Geosciences (GFZ)
Susanne Lunz
Technische Universität Berlin
Harald Schuh
German Research Centre for Geosciences (GFZ)
Technische Universität Berlin
Nataliya Zubko
Finnish Geospatial Research Institute (FGI)
Niko Petteri Kareinen
Finnish Geospatial Research Institute (FGI)
Journal of Geophysical Research: Solid Earth
21699313 (ISSN) 21699356 (eISSN)
Vol. 128 3 e2022JB025198Subject Categories (SSIF 2011)
Telecommunications
Other Physics Topics
Signal Processing
DOI
10.1029/2022JB025198