A Brief Review of Low-latitude Ionosphere: With Multi-frequency Observation Using GPS, NavIC, and GMRT

Abstract

A low-latitude ionosphere refers to the ionosphere region near the magnetic equator. Because of the horizontal orientation of the magnetic field at the geomagnetic equator, the equatorial and low-latitude ionosphere is the most dynamic and susceptible to sudden changes. Some features of this region include the Equatorial Ionization Anomaly (EIA), the Equatorial Electrojet (EEJ), and the equatorial plasma irregularities. Among the various techniques used to quantify and comprehend ionospheric perturbations and dynamics, two notable probes are GNSS/NavIC and Radio Interferometers (such as the indigenous Giant Metrewave Radio Telescope). These tools play prominent roles in studying and understanding the behavior of the ionosphere, offering valuable insights into this complex low-latitude ionospheric region. These methods aid in visualizing the ionosphere under various solar and geomagnetic disturbed or quiet conditions. This report provides a recent understanding of low-latitude ionosphere behavior with the help of GPS, NavIC, and GMRT observations. © 2025 selection and editorial matter, Dileep Kumar Gupta and Abhay Kumar Singh

individual chapters, the contributors.