Ionospheric Irregularities in GNSS Radio Occultation Data

Ankur Kepkar

GNSS radio occultation is based on satellite-satellite remote sensing technique. The general idea of this method is to track GNSS radio signal, as it passes through the Earth's atmosphere crossing Earth's limb. This weather independent method provides global data coverage, high accuracy and a high vertical resolution. Ionosphere being dispersive medium with free charge carriers affects the GNSS signal intensity to very large extent . The fundamental observable of this method is the bending angle '⍺'. Due to the refraction of the GPS electromagnetic waves induced by electron density gradients in Ionospheric altitudes, the GPS signals contain information on current Ionospheric conditions. Strong electron density gradients cause large fluctuations in the GPS signal amplitudes and Signal-to-Noise (SNR) profiles. The study will focus on GNSS radio occultation measurements performed by FORMOSAT-3/COSMIC satellites to detect disturbances especially in the Ionosphere.