Ultra-rapid earth rotation determination with VLBI during CONT11 and CONT14

Haas, Rüdiger; Hobiger, Thomas; Kurihara, Shinobu; Hara, Tetsuya

doi:10.1007/s00190-016-0974-x

Cited by 4 publications

(3 citation statements)

References 13 publications

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“…Using a European and a global GPS network, including three of the GPS stations used in this study, Meindl et al (2004) showed that the north gradient has a clear dependence on latitude when averaged over long timescales. For the area of interest in this study, we specifically mention the Icelandic low-pressure system that typically evolves in the winter and disappears in the summer (Hewson and Longley, 1944). This is a component in the North Atlantic Oscillation and the Arctic Oscillation (Thompson and Wallace, 1998;Sanchez-Franks et al, 2016).…”

Section: Cause Of Horizontal Gradients and Modelsmentioning

confidence: 99%

On the information content in linear horizontal delay gradients estimated from space geodesy observations

et al. 2019

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Abstract. We have studied linear horizontal gradients in the atmospheric propagation delay above ground-based stations receiving signals from the Global Positioning System (GPS). Gradients were estimated from 11 years of observations from five sites in Sweden. Comparing these gradients with the corresponding ones from the European Centre for Medium-Range Weather Forecasts (ECMWF) analyses shows that GPS gradients detect effects over different timescales caused by the hydrostatic and the wet components. The two stations equipped with microwave-absorbing material below the antenna, in general, show higher correlation coefficients with the ECMWF gradients compared to the other three stations. We also estimated gradients using 4 years of GPS data from two co-located antenna installations at the Onsala Space Observatory. Correlation coefficients for the east and the north wet gradients, estimated with a temporal resolution of 15 min from GPS data, can reach up to 0.8 for specific months when compared to simultaneously estimated wet gradients from microwave radiometry. The best agreement is obtained when an elevation cut-off angle of 3∘ is applied in the GPS data processing, in spite of the fact that the radiometer does not observe below 20∘. We also note a strong seasonal dependence in the correlation coefficients, from 0.3 during months with smaller gradients to 0.8 during months with larger gradients, typically during the warmer and more humid part of the year. Finally, a case study using a 15 d long continuous very-long-baseline interferometry (VLBI) campaign was carried out. The comparison of the gradients estimated from VLBI and GPS data indicates that a homogeneous and frequent sampling of the sky is a critical parameter.

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Section: Cause Of Horizontal Gradients and Modelsmentioning

confidence: 99%

On the information content in linear horizontal delay gradients estimated from space geodesy observations

et al. 2019

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“…This supremacy of the baseline with Hobart is in fact beneficial for the SI program in view of a routine operation that should provide rapid service UT1−UTC. The general concept of e-VLBI and ultra-rapid operations for Earth rotation determination is described in Sekido et al (2008) and Haas et al (2017). Since the station Yarragadee does not facilitate e-transfer of the observation data, UT1− UTC cannot be delivered rapidly from the full SI baseline configuration.…”

Section: Conclusion and Future Perspectivesmentioning

confidence: 99%

Probing a southern hemisphere VLBI Intensive baseline configuration for UT1 determination

Böhm

Gruber

et al. 2022

Earth Planets Space

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The deviation of Universal Time from atomic time, expressed as UT1−UTC, reflects the irregularities of the Earth rotation speed and is key to precise geodetic applications which depend on the transformation between celestial and terrestrial reference frames. A rapidly varying quantity such as UT1−UTC demands observation scenarios enabling fast delivery of good results. These criteria are currently met only by the Very Long Baseline Interferometry (VLBI) Intensive sessions. Due to stringent requirements of a fast UT1−UTC turnaround, the observations are limited to a few baselines and a duration of one hour. Hence, the estimation of UT1−UTC from Intensives is liable to constraints and prone to errors introduced by inaccurate a priori information. One aspect in this context is that the regularly operated Intensive VLBI sessions organised by the International VLBI Service for Geodesy and Astrometry solely use stations in the northern hemisphere. Any potential systematic errors due to this northern hemisphere dominated geometry are so far unknown. Besides the general need for stimulating global geodetic measurements with southern observatories, this served as a powerful motivation to launch the SI (Southern Intensive) program in 2020. The SI sessions are observed using three VLBI antennas in the southern hemisphere: Ht (South Africa), Hb (Tasmania) and Yg (Western Australia). On the basis of UT1−UTC results from 53 sessions observed throughout 2020 and 2021, we demonstrate the competitiveness of the SI with routinely operated Intensive sessions in terms of operations and UT1−UTC accuracy. The UT1−UTC values of the SI reach an average agreement of 32 µs in terms of weighted standard deviation when compared with the conventional Intensives results of five independent analysis centers and of 27 µs compared with the 14C04 series. The mean scatter of all solutions of the considered northern hemisphere Intensives with respect to C04 is at a comparable level of 29 µs. The quality of the results is only slightly degraded if just the baseline HtHb is evaluated. In combination with the e-transfer capabilities from Ht to Hb, this facilitates continuation of the SI by ensuring rapid service UT1−UTC provision. Graphical Abstract

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“…The CONT08 observations were processed by OCCAM and the stronger diurnal ERP signals in summer were detected (Sun et al 2010). The ultra-rapid Earth rotation results were obtained by processing the CONT11 and CONT14 observations, and the results showed that the CONT results agree with IERS 08 C04 in terms of standard deviation during CONT11 on the level of 16-22 µs, but for CONT14 on the level of 9-12 µs (Haas et al 2016). The model of the diurnal and semidiurnal variations in ERP due to lunisolar tides in the world ocean influenced the ERP estimation of the VLBI experiment (Gubanov et al 2015).…”

Section: Introductionmentioning

confidence: 97%

Comparative Analysis of Earth Rotation Parameters Using VLBI Observations During CONT and GNSS Observations

Sun

et al. 2022

Preprint

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The Earth rotation parameters mainly include the displacement and rate of the Earth's poles, length of day, which can be estimated based on VLBI and GNSS. In order to obtain the ERP results with higher accuracy, two VLBI data processing schemes were compared. VLBI observations during 2008, 2011, 2014, and 2017 are processed with VieVS. In addition, the experiments to estimate ERP using CONT08, CONT11, CONT14, and CONT17 campaigns were also designed. The results showed that the higher accuracy of ERP were calculated using CONT campaigns. At the same time, ERP estimations using the 86 globally distributed GNSS observatories data during the same period were processed by GAMIT. The ERP results from the CONT campaigns and GNSS observations estimated were then combined in a weighted manner, based on the Helmert variance component estimation and the IERS14 C04 sequences, respectively. The weighted results showed that the Root Mean Square Error (RMSE) of polar motion was about between 0.05 and 0.10 mas, and the RMSE in UT1-UTC ranged from 0.005 and 0.02 ms.

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Ultra-rapid earth rotation determination with VLBI during CONT11 and CONT14

Cited by 4 publications

References 13 publications

On the information content in linear horizontal delay gradients estimated from space geodesy observations

On the information content in linear horizontal delay gradients estimated from space geodesy observations

Probing a southern hemisphere VLBI Intensive baseline configuration for UT1 determination

Comparative Analysis of Earth Rotation Parameters Using VLBI Observations During CONT and GNSS Observations

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