Investigation of Ionospheric Effects in the Planning of the AlfaCrux UHF Satellite Communication System

Abstract

Recent technological advances and new launch opportunities have allowed the development and spread of small satellite missions for commercial and educational purposes and different applications. Among this category of small satellites, CubeSats have attracted lots of attention given their low design-and-deployment costs. Such satellites usually operate in the narrow ranges of the UHF frequency band to perform the communication activities. Although it provides lower data rate, the use of narrowband can be advantageous when compared to broadband, due to its better penetration and lower attenuation in the troposphere. However, the signals in this frequency band can be significantly affected by the ionosphere. This work investigates the ionospheric effects, namely the Faraday rotation and scintillation, on the UHF satellite communication systems, taking as a case study the AlfaCrux CubeSat mission, which is an 1U CubeSat mission planned for conducting research activities in the field of satellite-mediated communication. In particular, we investigate the variability of Faraday rotation and amplitude scintillation with the daytime, season, and geographic position for periods of low and high solar activity. In addition, this work presents a methodology of risk estimation for communication outage over the Brazilian sector. Aiming to address the most realistic communication scenario, we include in this analysis the effects due to scintillation, free-space propagation, tropospheric attenuation, and polarization losses. By doing so, the regions with the high risk of communication outage may be estimated in advance and used for optimal mission planning.