AVAILABILITY AND PERFORMANCE ASSESSMENT OF MULTI-GNSS RADIO OCCULTATION DATA

Abstract

Occultation, which occurs when one celestial body ceases to be visible due to the superposition of another, has been widely used with stars and probes to study the atmosphere of other planets using a technique so-called radio occultation (RO). The advance of GNSS (Global Navigation Satellite Systems) missions and LEO (Low Earth Orbit) satellites has allowed RO to be applied to the exploration and analysis of the Earth's atmosphere. RO is based on the principle that the signals sent by GNSS satellites are affected by the atmosphere (neutral and ionized) as they pass through it. This interaction during signal propagation makes it possible to calculate the refractive indices of the atmosphere, making it possible to extract atmospheric profiles such as humidity, pressure, temperature and electron density. Since the first RO mission, several others have been launched, making many products available. One of the most recent, the COSMIC-2 (Constellation Observing System for Meteorology, Ionosphere and Climate) mission, provides not only occultations made with GPS (Global Positioning System) satellites, but also from other GNSS systems. In this context, this research aims to analyze and validate the availability and performance of multi-GNSS RO profiles for the Brazilian region. In addition, the project aims to investigate methods of validating RO data, through comparisons between missions or different data sources.