Ionospheric Measurement Using a Linearly Polarized Tri-Band Small Satellite Beacon

Radio waves propagating the ionosphere are subject to a number of unpredictable and corrupting effects, the most significant of which are phase path reduction, Faraday rotation, and scintillation. A method of measuring these effects is therefore necessary in order to study, understand and anticipate their impact. The rise in popularity of small satellites presents a new cost-effective opportunity to study the ionosphere in detail, however the challenge of realizing a beacon within the constraints of a CubeSat system must be overcome. First we introduce a measurement technique that builds on past multi-frequency beacons, incorporating the well established differential phase technique, as well as introducing a new differential polarization technique. We achieve this by employing linearly polarized beacon signals, which enables us to separate phase path reduction and Faraday rotation into a phase and polarization change respectively. The introduction of linear polarization overcomes some of the key limitations in current ionospheric measurement techniques: eliminating errors associated with indirect Faraday rotation measurement, and enabling absolute unambiguous parameter measurement. To validate the capability of measuring the ionosphere within the constraints of a small satellite package, we establish the influence of system noise, weak scattering, clock errors and antenna characteristics on the measurement technique. We then use this to inform a practicable CubeSat beacon design solution which achieves absolute and high resolution measurement of ionospheric parameters within the constraints of the system.