Detection of low frequency radio signals from space

Abstract

Low-frequency radio astronomy, particularly in the spectrum below 30 MHz, provides a unique opportunity to explore astronomical phenomena such as Auroral Kilometric Radiation, Magnetic reconnection event & Geotail, Galactic emissions, Interplanetary medium dynamics, and Heliosphere. This thesis examines the scientific potential and technical challenges associated with conducting radio astronomy at frequencies below 30 MHz, an area that remains largely unexplored due to limitations imposed by Earth’s ionosphere. Ground-based observations in this spectrum are severely affected by radio frequency interference (RFI) and ionospheric cutoffs, making space-based observations essential. The research presented here addresses these challenges by developing new algorithms and techniques for source localization and investigating space weather phenomena using low-frequency radio observations. A key contribution of this thesis is the development of the Snapshot Averaged matrix pencil Method (SAM), which enhances the Direction-of-Arrival (DoA) estimation for the SEAMS mission, designed to explore radio frequencies below 16 MHz. The SAM-DoA algorithm improves the accuracy of estimating the direction and polarization of electromagnetic waves, and its applicability to various antenna designs is demonstrated.