| Name: Tanmay Das |
| Affiliation: NCRA-TIFR |
| Conference ID: ASI2026_209 |
| Title: Understanding the ionosphere above the GMRT using GNSS TEC data |
| Abstract Type: Poster |
| Abstract Category: Facilities, Technologies and Data science |
| Author(s) and Co-Author(s) with Affiliation: Tanmay Das(National Centre for Radio Astrophysics,Tata Institute of Fundamental Research (NCRA-TIFR), Pune -411007, India), Sarvesh Mangla(University Observatory, Faculty of Physics, Ludwig-Maximilians-Universität, Scheinerstr. 1, 81679, Munich, Germany), Divya Oberoi(National Centre for Radio Astrophysics,Tata Institute of Fundamental Research (NCRA-TIFR), Pune -411007, India), Navnath Shinde(National Centre for Radio Astrophysics,Tata Institute of Fundamental Research (NCRA-TIFR), Pune -411007, India) |
| Abstract: The Giant Metrewave Radio Telescope (GMRT) is located at lat: 19.10°N, long: 74.05°E, geographic; dip: 23°N magnetic. This region lies in the vicinity of the Equatorial Ionization Anomaly (EIA), a dominant low-latitude ionospheric feature which shows significant dynamics and has a considerable impact on trans-ionospheric radio signal propagation. These effects of ionospheric propagation are especially important at the metrewave part of the spectrum where the GMRT operates. Additionally, for linearly polarization studies, ionospheric Faraday rotation (FR) introduces a potentially significant contamination in the measured polarization signals. Global Navigation Satellite System (GNSS) based Total Electron Content (TEC) measurements have long been used in characterizing the ionosphere on a global scale. In this paper we explore the use of GNSS-TEC measurements for addressing the ionospheric challenges for the upgraded GMRT (uGMRT). The International Reference Ionosphere (IRI) empirical model, which has evolved and improved since the 1960s and is a vital resource for ionospheric characterization, has been used as a fiducial reference for this study. This study aims at understanding and quantifying the limitations imposed by the use of simple mapping functions routinely employed across the community to convert the slant-TEC (STEC) measured towards the lines-of-sight to the GNSS satellites to the TEC in the vertical column towards the local zenith, vertical-TEC (VTEC) in the GMRT sector. An effort has also been made to quantify systematic differences, if any, between the data derived from the IRI model and the GNSS datasets. Furthermore, investigation has been made to estimate the range of ionospheric FR contamination by employing these two datasets. The GNSS data used in these studies were obtained from two stations: one located at the uGMRT and the other at NCRA (lat: 18.55°N, long: 73.80°E, geographic; dip: 23°N magnetic), which is approximately 80 km South-East of the uGMRT.
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