Imaging ionosphere's wave like structure using interferometry data

Abstract

The ionosphere is an ionised region in the Earth's upper atmosphere, which significantly impacts radio signal propagation by refracting and reflecting them. As a result, ionospheric disturbances can degrade the performance of navigation, communication, and space-based systems. Understanding the dynamics and processes of the ionosphere is essential, leading to significant advancements in instrumentation and analytical techniques. This study presents an ionospheric imaging technique using interferometric data. Radio interferometers, such as the Giant Meter-wave Radio Telescope (GMRT), are highly sensitive to phase fluctuations, enabling the detection of total electron content (TEC) variations with a precision of 10-3TECu and TEC gradients with an accuracy of approximately 7×10-4TECukm-1. We introduce an antenna-based approach for constructing phase screens using measured TEC gradients for each interferometric baseline by employing a surface reconstruction algorithm. To incorporate the necessary integral constant as a boundary condition, we utilized output from the International Reference Ionosphere (IRI-2016) model. The generalized least squares method was applied to ensure an optimal reconstruction of the ionospheric phase screen, enhancing the accuracy of ionospheric imaging. © 2025 Elsevier B.V., All rights reserved.