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<div class="csl-entry">LAHA, A., Schartner, M., Soja, B., Böhm, J., Balasubramanian, N., & Dikshit, O. (2024, December 9). <i>Evaluating Intensive Baseline Precision with a Future Indian VGOS Telescope: A Comparative Study</i> [Poster Presentation]. AGU Fall Meeting 2024, Washington, United States of America (the). http://hdl.handle.net/20.500.12708/207527</div>
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dc.identifier.uri
http://hdl.handle.net/20.500.12708/207527
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dc.description.abstract
Irregularities in the Earth’s rotation speed are quantified by the difference between the Universal Time (UT1) and the Coordinated Universal Time (UTC). This precise observable is expressed as UT1-UTC and only estimated through Very Long Baseline Interferometry (VLBI). Typically, 1-hour sessions, known as Intensives, are conducted daily between two to three stations, with the primary goal of determining UT1-UTC with a short latency. These intensive sessions, organized by the International VLBI Service for Geodesy and Astrometry (IVS), are limited to few baselines and primarily use stations in the northern hemisphere. To achieve the IVS’s strategic vision in the next ten years, it is necessary to organize twice daily 1-hour intensive sessions to meet the accuracy requirement of 1 μs for UT1-UTC estimation. With the proposed plan of India having its own VLBI Global Observing System (VGOS) telescope, it is necessary to identify the optimal location of the VGOS telescope and the ways it can help the IVS to improve the precision of UT1-UTC. This study investigates the change in precision of different baseline solutions when a third station from India is added in both regular mode and tag-along mode. Additionally, it identifies a new baseline, which includes one Indian station, that could be part of future Intensive sessions. Extensive simulations were conducted using VieSched++ software, varying the VGOS telescope’s location in India on a regular 5 × 5 degree grid. The simulated data, with the Indian telescope as third station, were compared with different baseline solutions: three from the northern hemisphere (NH), two from the southern hemisphere (SH) and one passing through the equator. To identify the new baseline including India, the second station is chosen from the current and future VGOS telescopes of different countries. The results reveal that adding an Indian station in regular mode does not improve the precision of the baseline solutions, except for the one passing through the equator. However, it improves the precision of the southern baseline solutions when an Indian station is added in tag-along mode. Additionally, it is observed that baselines with a first station in India and a second station in the USA have an average mean formal error (MFE) of less than 20 μs for all possible locations in India. This level of error is comparable to the average MFE of the baseline solutions in the NH. Finally, the study concludes that the optimal location for a VGOS telescope in India for UT1-UTC estimation is in the northeastern part of the country.
en
dc.language.iso
en
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dc.subject
VLBI
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dc.subject
Earth rotation
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dc.title
Evaluating Intensive Baseline Precision with a Future Indian VGOS Telescope: A Comparative Study
