Evaluation of Dynamic Attributes and Variability of Ionospheric Slant Total Electron Content Using NavIC Satellite System

Abstract

The ionosphere is an inhomogeneous and anisotropic medium in nature. It causes degradation in the performance of positioning through Global Navigation Satellite Systems (GNSS). Generally, the vertical total electron content (VTEC) is used to characterize the ionosphere. The present study can further be used to enhance positional accuracy with a Navigation with Indian Constellation (NavIC) dual-frequency receiver, especially in the Northern region of India where the elevation angle is consistently very low. At such low elevation angles, converting Slant Total Electron Content (STEC) to VTEC and vice versa introduces errors. Therefore, in this study, STEC is used directly instead of VTEC. STEC can be used to analyze dynamic variations in the ionosphere and investigate local and regional ionospheric disturbances. The STEC is dependent on various factors such as solar activity, elevation and azimuth angle of the satellite, seasonal variation etc. Therefore, it is necessary to evaluate the dynamic attributes and variability of STEC to maintain high accuracy in any ionospheric conditions. This research paper focuses on the evaluation of dynamic attributes and variability of Ionospheric Slant Total Electron Content using Navigation with Indian Constellation (NavIC) satellite system. This study utilizes 19 months (from June 2017 to December 2018) dual frequency NavIC data to compute and analyze STEC. The results show a significant effect of satellite elevation angle, azimuth angle, and seasonal STEC variability. The discussion highlights the suitability of NavIC geostationary satellites (PRN3, PRN6, and PRN7) of NavIC for ionospheric studies, space weather applications, and identification of local ionospheric irregularities. The research findings demonstrate the importance of considering dynamic attributes and variability of STEC to model applications for maintaining high accuracy in case of any ionospheric irregularity. Additionally, this research could serve as a reference for future studies in the field of ionospheric-plasmapheric studies and space weather applications using NavIC system.