Fading of Wideband Signals Due to Propagation Through Equatorial Plasma Bubbles and Diversity Mitigation Effects

Abstract

Equatorial Plasma Bubbles (EPBs) and their ionospheric density irregularities exhibit structures with scale sizes that can vary from several hundred kilometers to tens of meters. These random irregularities degrade both the performance and the availability of space-based communication and navigation systems, in different ways. As examples of effects to be analyzed, wideband UHF (360 MHz – 380 MHz) transmissions received by Ascension Island (7.93°S, 14.25°W) monitors during an observational campaign in October 2016 displayed flat-fading and frequency-selective fading conditions. In this report, the ionospheric structures that are responsible for the harmful observed behavior (flat and frequency-selective fading) will initially be identified, through the application of a discrete version of the single phase-screen formulation to low-and high-resolution in-situ ion density data recorded by the Planar Langmuir Probe (PLP) onboard the Communications/ Navigation Outage Forecasting System (C/NOFS) satellite. Next, the resulting hypothesis will be confirmed, by the application of the continuous version of the same formulation to single-scale irregularities with different scale sizes. Finally, mitigation effects from space and frequency diversity on the observed behavior will be discussed, with basis on the application of the initial formulation to the high-resolution C/NOFS PLP data.