Global ionospheric imaging is currently limited by a lack of significant quantities of observations over the oceans. This deficiency of... Show moreGlobal ionospheric imaging is currently limited by a lack of significant quantities of observations over the oceans. This deficiency of measurements arises because coverage from Global Navigation Satellite System (GNSS) remote sensing tools is typically limited to regions over land by using ground-based receivers. This dissertation presents the opportunity to estimate ionospheric data over the oceans by using reflected GNSS signals received by the upcoming Low-Earth Orbit (LEO) satellite constellation Cyclone Global Navigation Satellite System (CYGNSS). CYGNSS is currently being developed by NASA primarily for hurricane predictions. Its eight micro-satellites will have a single-frequency Global Positioning System (GPS) receiver onboard and zenith and nadir antennas that collect GPS signals reflecting from the ocean surface of Earth. This study investigates the possibility of leveraging CYGNSS for a secondary science mission, using GNSS-Reflectometry for ionospheric remote sensing. A mathematical model is developed that retrieves ionospheric electron content by using ranging measurements from direct and ocean-reflected GPS signals onboard CYGNSS satellites. The measurement model terms can be grouped as geometric raypath and signal refraction components due to the troposphere and the ionosphere. Each term of the model is analyzed and quantified by applying fundamental physical principles and empirical models. The implementation of a multi-orbit simulation estimates the magnitudes of anticipated electron content measurements with CYGNSS. M.S. in Mechanical and Aerospace Engineering, December 2013 Show less
