On the Improvement of Combined EOP Series by Adding 24-h VLBI Sessions to VLBI Intensives and GNSS Data

Lengert, Lisa; Thaller, Daniela; Flohrer, Claudia; Hellmers, Hendrik; Girdiuk, Anastasiia

doi:10.1007/1345_2022_175

Cited by 2 publications

(1 citation statement)

References 14 publications

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“…In the following, we will not go into more detail about the results of the session-wise and multi-day , as they are covered in an other publication. These can be found in Lengert et al (2022).…”

Section: Resulting Ut1-utc Seriesmentioning

confidence: 97%

Intra-Technique Combination of VLBI Intensives and Rapid Data to Improve the Temporal Regularity and Continuity of the UT1-UTC Series

Klemm,

Thaller,

Flohrer

et al. 2024

International Association of Geodesy Symposia

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The difference UT1-UTC is the most variable quantity among the Earth Orientation Parameters (EOP) with significant unpredictable variation. It can be measured only with the quasi-space-fixed technique VLBI. The IVS organizes two different VLBI observation campaigns: The bi-weekly 24-hour Rapid campaigns and the daily 1-hour Intensive sessions. As a result, two independent UT1-UTC time series are estimated and published as official IVS EOP-S and EOP-I products. These have different strengths and weaknesses in terms of continuity and accuracy, but both are characterized by irregular temporal resolution. We present the current activities of BKG towards a combined processing of VLBI Intensive and Rapid data in one common adjustment. In this way, we unify the strengths of both sessions and generate a UT1-UTC time series characterized by a daily, continuous and temporally regular resolution, e.g., at 12:00 UTC. We achieved a significant improvement in accuracy of 35% lower WRMS values compared to the regular session-wise Intensive-only solution. By using a continuous EOP parameterization, the accuracy is almost at a constant level and less dependent on the irregularity of the VLBI observation period. The processing is based on homogenized, datum-free NEQs which allow a rigorous combination on the normal equation level instead of the observation level. Based on the improved combination method, we intend to set up a new operational VLBI EOP product at BKG. Its characteristics make it suitable as an input for EOP prediction algorithms.

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Section: Resulting Ut1-utc Seriesmentioning

confidence: 97%

Intra-Technique Combination of VLBI Intensives and Rapid Data to Improve the Temporal Regularity and Continuity of the UT1-UTC Series

Klemm,

Thaller,

Flohrer

et al. 2024

International Association of Geodesy Symposia

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Consistently Combined Earth Orientation Parameters at BKG—Extended by New VLBI Intensives Data

Klemm,

Thaller,

Flohrer

et al. 2024

International Association of Geodesy Symposia

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The Earth Orientation Parameters (EOPs) describe the rotation between the Terrestrial Reference Frame and the Celestial Reference Frame and represent an essential component of the Global Geodetic Reference Frame. This study presents the current activities of BKG in the area of combined processing of GNSS and VLBI data in one common adjustment with the main objective to generate a consistent combined EOP time series. In earlier studies, we have investigated different combination approaches using VLBI and GNSS data. We generate EOP series with latencies of about one to 14 days, depending on the input data we used. In this way, a significant improvement in accuracy compared to the individual technique-specific solutions was achieved, especially for the highly variable component dUT1. The combination process starts at the level of normal equations using an EOP parameterization with piece-wise linear offsets and a temporal resolution of one day. Our main objective is to generate a continuous, daily and regular EOP product with the shortest possible latency. The requirement for achieving these characteristics is the daily and rapid availability of the input data. In particular, the VLBI Intensive (INT) sessions play an important role in the precise and rapid estimation of the UT1-UTC component. Since 2020, an increasing number of VLBI Global Observing System (VGOS) INT campaigns has been conducted in addition to the legacy S/X INT sessions. The VGOS network is under continuous extension and the accuracy and latency of the VGOS INT sessions are at least at the level of the legacy S/X sessions. Therefore, an inclusion of the VGOS INT data is beneficial for rapid EOP estimation. The integration of the VGOS data into the combination process results in a constant slight decrease of the Weighted Root Mean Square (WRMS) level of the UT1-UTC residuals in comparison to the external EOP series. The growing number of available INT sessions with independent networks, up to four per day, increases the continuity and reliability of the combined EOP solution.

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On the Improvement of Combined EOP Series by Adding 24-h VLBI Sessions to VLBI Intensives and GNSS Data

Cited by 2 publications

References 14 publications

Intra-Technique Combination of VLBI Intensives and Rapid Data to Improve the Temporal Regularity and Continuity of the UT1-UTC Series

Intra-Technique Combination of VLBI Intensives and Rapid Data to Improve the Temporal Regularity and Continuity of the UT1-UTC Series

Consistently Combined Earth Orientation Parameters at BKG—Extended by New VLBI Intensives Data

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