Consistency and precision of very long baseline interferometry source coordinate time series

@misc{zhang2026consistency,
  title = {{Consistency and precision of very long baseline interferometry source coordinate time series}},
  author = {X. -X. Zhang and N. Liu and S. B. Lambert and K. Le Bail and H. Krásná and O. Titov and M. Karbon and T. Nilsson and Z. Zhu and J. -C. Liu and I. N. Huda and J. Yang and X. -P. Cheng and B. -W. Sohn and F. -C. Shu and X. He and Z. -W. Wang and Z. -Y. Zhang and H. -F. Yu and J. Yao and D. -D. Zhang},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2609.13681},
  eprint = {2609.13681},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.13681},
}

TY  - UNPB
TI  - Consistency and precision of very long baseline interferometry source coordinate time series
AU  - X. -X. Zhang
AU  - N. Liu
AU  - S. B. Lambert
AU  - K. Le Bail
AU  - H. Krásná
AU  - O. Titov
AU  - M. Karbon
AU  - T. Nilsson
AU  - Z. Zhu
AU  - J. -C. Liu
AU  - I. N. Huda
AU  - J. Yang
AU  - X. -P. Cheng
AU  - B. -W. Sohn
AU  - F. -C. Shu
AU  - X. He
AU  - Z. -W. Wang
AU  - Z. -Y. Zhang
AU  - H. -F. Yu
AU  - J. Yao
AU  - D. -D. Zhang
PY  - 2026
DA  - 2026/10/19
PB  - arXiv
DO  - 10.48550/arxiv.2609.13681
UR  - https://arxiv.org/abs/2609.13681
AB  - Coordinate time series of extragalactic radio sources from very long baseline interferometry observations are widely used to evaluate source positional stability, select stable sources for celestial reference frames, assess reference-frame axis stability, and investigate source-related astrometric variability. Their external consistency, realistic errors, and relation to processing strategies and analysis configurations remain to be investigated. We aim to compare coordinate time series solutions from different analysis centers and investigate how processing strategies and configurations contribute to their differences. We collected eight solutions from seven analysis centers and selected 496 common sources after data selection, reference-frame alignment, and extraction of common observing sessions. Inter-solution differences were characterized with pairwise positional offsets and correlation analysis, and realistic positional errors with the N-cornered-hat (NCH) method and bootstrap resampling. Most solutions have median weighted root mean square (WRMS) values of a few hundred microarcseconds (μas), and the median NCH-derived precision is about 200-300 μas in right ascension and 250-400 μas in declination. Solutions with similar strategies, software, or source constraints show higher consistency, with more similar WRMS values, stronger correlations, and closer precision estimates. Consistency is affected not only by the global or independent mode distinction but also by detailed analysis configuration. NCH-derived precision depends on declination, being poorer in the southern sky, and stabilizes with more observing sessions. Processing strategies and configurations introduce marginal differences; solutions remain generally consistent. Inter-solution comparisons independently estimate realistic stochastic errors beyond formal errors.
ER  -