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Main Title: Improving the modeling of the atmospheric delay in the data analysis of the Intensive VLBI sessions and the impact on the UT1 estimates
Author(s): Nilsson, Tobias
Soja, Benedikt
Balidakis, Kyriakos
Karbon, Maria
Heinkelmann, Robert
Deng, Zhiguo
Schuh, Harald
Type: Article
Abstract: The very long baseline interferometry (VLBI) Intensive sessions are typically 1-h and single-baseline VLBI sessions, specifically designed to yield low-latency estimates of UT1-UTC. In this work, we investigate what accuracy is obtained from these sessions and how it can be improved. In particular, we study the modeling of the troposphere in the data analysis. The impact of including external information on the zenith wet delays (ZWD) and tropospheric gradients from GPS or numerical weather prediction models is studied. Additionally, we test estimating tropospheric gradients in the data analysis, which is normally not done. To evaluate the results, we compared the UT1-UTC values from the Intensives to those from simultaneous 24-h VLBI session. Furthermore, we calculated length of day (LOD) estimates using the UT1-UTC values from consecutive Intensives and compared these to the LOD estimated by GPS. We find that there is not much benefit in using external ZWD; however, including external information on the gradients improves the agreement with the reference data. If gradients are estimated in the data analysis, and appropriate constraints are applied, the WRMS difference w.r.t. UT1-UTC from 24-h sessions is reduced by 5% and the WRMS difference w.r.t. the LOD from GPS by up to 12%. The best agreement between Intensives and the reference time series is obtained when using both external gradients from GPS and additionally estimating gradients in the data analysis.
Subject(s): VLBI
Universal time 1
length of day
Kalman filter
tropospheric gradients
Issue Date: 11-Jan-2017
Date Available: 29-Apr-2021
Language Code: en
DDC Class: 550 Geowissenschaften
Journal Title: Journal of Geodesy
Publisher: Springer
Volume: 91
Publisher DOI: 10.1007/s00190-016-0985-7
Page Start: 857
Page End: 866
EISSN: 1432-1394
ISSN: 0949-7714
TU Affiliation(s): Fak. 6 Planen Bauen Umwelt » Inst. Geodäsie und Geoinformationstechnik » FG Satellitengeodäsie
Appears in Collections:Technische Universität Berlin » Publications

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