Conference ID : ASI2022_202
Title : STARFIRE: An algorithm for estimating radio frequency interference in orbits around Earth
Authors : Sonia Ghosh, Mayuri S Rao, Saurabh Singh
Abstract Type: Oral
Abstract Category : Instrumentation and Techniques
Abstract : A number of ground- and space-based experiments are attempting to detect the faint redshifted global 21-cm signal arising from the Cosmic Dawn (CD) and Epoch of Reionization (EoR). Ground-based experiments face three unique challenges, namely i) ionospheric distortions ii) coupling of the antenna properties to the Earth beneath and iii) terrestrial radio frequency interference (RFI). Terrestrial RFI is particularly challenging as the FM radio band spanning over 87-108 MHz lies entirely within the frequency range of experiments targeting the 21-cm signal from CD/EoR (~40-250 MHz). Several space-based experiments have been proposed to operate in the radio-quiet region on the lunar farside. PRATUSH (Probing ReionizATion of the Universe using Signal from Hydrogen) is a proposed lunar orbiter experiment from India with a primary science goal of detecting the sky-averaged 21-cm signal from CD/EoR on the lunar farside. An intermediate option in cost and complexity is deploying an experiment in space in an orbit around Earth. Our algorithm - STARFIRE (Simulation of TerrestriAl Radio Frequency Interference in oRbits around Earth) - provides an expectation of RFI in the FM band at different altitudes and spectral variation around Earth. STARFIRE uses, as its input, a database of FM transmitters from around the world. Applications of STARFIRE include identifying relatively RFI clean orbits around Earth, generating RFI heatmaps and spectra. STARFIRE can be easily adapted for different frequencies, altitudes, antenna properties, and terrestrial RFI databases. In this work, we explore low-interference orbits around Earth for a PRATUSH like CD/EoR experiment.