Impact of Tropospheric Ties on UT1‐UTC in GNSS and VLBI Integrated Solution of Intensive Sessions

Wang, Jungang; Ge, Maorong; Glaser, Susanne; Balidakis, Kyriakos; Heinkelmann, Robert; Schuh, Harald

doi:10.1029/2022jb025228

Cited by 2 publications

(2 citation statements)

References 72 publications

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“…The cutoff satellite elevation was set to 7 degrees, and the weights of observations were determined depending on elevation. The BDS-3 data over 365 days from 18 August 2020 to 17 August 2021 was processed with the Positioning And Navigation Data Analyst software (PANDA) version 1.0 [21,38,39] which was used to estimate ERPs and other parameters from BDS-3 observations, in which each OD run was set for an orbit arc of 24 h, resulting in 365 runs. In this processing, the Phase Center Offset (PCO) values provided by the Operational Control Center (OCC) were used for the BDS3 satellites, while Phase Center Variation (PCV) values were ignored.…”

Section: Estimating Erps From Bds-3 Observationsmentioning

confidence: 99%

“…On the other hand, the GNSS technique provides an abundantly continuous signal, a stable and wide constellation of satellites, and a globally distributed network of ground stations, which is helpful to obtain good results when estimating short-term ERPs [16][17][18]. Integration of a few techniques together will produce reliable and continuous ERP estimates, as shown in studies on combining the earth orientation parameters from GNSS and VLBI [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

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Estimation of Earth Rotation Parameters Based on BDS-3 and Discontinuous VLBI Observations

Wang,

Sang,

et al. 2024

Remote Sensing

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Earth rotation parameters (ERPs) are fundamental to geodetic and astronomical studies. With its high measurement accuracy and stability, the Very Long Baseline Interferometry (VLBI) plays an irreplaceable role in estimating the ERPs and maintaining the earth reference frame. However, the imperfect global station distribution, observation discontinuity, and vast cost of the VLBI make the GNSS a more attractive technique. In 2020, the third generation of the BeiDou Navigation System (BDS), namely BDS-3, was constructed completely. In this study, we conducted a series of experiments to estimate Earth’s rotation parameters based on the continuous BDS-3 observation data, the discontinuous VLBI observation data, and the combined BDS-3 and discontinuous VLBI observation data. We used two methods, namely the weighted averaging method and the normal equation combination method, to obtain ERP combination solutions. The results are compared with the International Earth Rotation and Reference Systems Service (IERS) EOP 20C04 at 00:00:00 UTC. Final results show that (a) the estimation accuracy becomes stable when the number of BDS-3 tracking stations is more than 40. At the same time, both the number of stations and the volume of polyhedrons formed by the observing stations affect the accuracy of the ERPs estimated by the BDS-3 or VLBI. (b) Results have also shown that the inclusion of the BDS-3 IGSO and GEO satellites contributes little to the ERP estimation. (c) For the BDS-3-only MEO satellites solution, the root mean square (RMS) was 113.2 µas, 102.8 µas, and 13.1 µs/day for X-pole coordinate, Y-pole coordinate, and length of day (LOD), respectively. For the VLBI solution, the RMSs of the X-pole, Y-pole, and LOD were 100.4 µas for the X-pole, 94.2 µas for the Y-pole, and 14.1 µs/day. The RMS was 82.6 µas, 70.3 µas, and 10.5 µs/day for the combined X-pole, Y-pole, and LOD using the weighted averaging method. It was 78.2 µas, 62.6 µas, and 8.6 µs/day when the normal equation combination method was applied. This demonstrates that by taking advantage of the BDS-3 and VLBI technique combinations, accuracy in estimating the ERPs can be improved over that using either of them, in addition to enhanced stability and reliability.

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Section: Estimating Erps From Bds-3 Observationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Estimation of Earth Rotation Parameters Based on BDS-3 and Discontinuous VLBI Observations

Wang,

Sang,

et al. 2024

Remote Sensing

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On the importance of accurate pole and station coordinates for VLBI Intensive baselines

Kern,

Schartner,

Böhm

et al. 2023

J Geod

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Very long baseline interferometry (VLBI) is a geodetic technique capable of deriving the complete set of Earth orientation parameters, including the highly variable Earth’s phase of rotation. This observable can be expressed through UT1–UTC, the difference between the Universal Time and the Coordinated Universal Time. The so-called Intensive sessions, or Intensives, are typically 1-h sessions between two to three stations that are observed daily with the primary goal of determining UT1–UTC with a short latency. In this publication, we examine the impact of erroneous a priori information on the UT1–UTC estimation with VLBI Intensive sessions in a systematic way and on a global scale. Our findings are based on a simulation study which is carried out on a regular $$10 \times 10$$ 10 × 10 degree grid of artificial telescopes. In the simulations, realistic errors are introduced in the station coordinates, polar motion and nutation to get a global picture of the impact of these errors on the estimation of UT1–UTC. Our results reveal that in contrast to errors in the horizontal components of the station coordinates, an error in the station height only slightly affects the UT1–UTC estimate. North–south-oriented baselines are in general strongly affected by errors in the a priori information. In all cases, very short and very long baselines as well as baselines with a midpoint close to the equatorial plane are less robust. On the other hand, east–west-oriented baselines, except equatorial baselines, seem to be rather resistant against errors of these a priori values.

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Impact of Tropospheric Ties on UT1‐UTC in GNSS and VLBI Integrated Solution of Intensive Sessions

Cited by 2 publications

References 72 publications

Estimation of Earth Rotation Parameters Based on BDS-3 and Discontinuous VLBI Observations

Estimation of Earth Rotation Parameters Based on BDS-3 and Discontinuous VLBI Observations

On the importance of accurate pole and station coordinates for VLBI Intensive baselines

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