A Technique for Passive Ionosphere Sounding Based on Incident Wave Doppler Evaluation

The present paper proposes and tests an ionosphere sounding technique designed to evaluate the Doppler shift determined by oblique sky-wave propagation on high frequency radio waves. To this end, preexisting radio infrastructure components - consisting of a broadcast emitter and three KiwiSDR receivers - were employed, based on two software applications developed in Python and Matlab. The novelty of the proposed technique stems from the lack of dedicated sounding infrastructure, which renders the entire measurement approach low-cost. The experimental testing of the algorithm under discussion is performed through three 24hour study scenarios that revolve around two sky wave oblique sounding channels and a direct wave propagation channel. As anticipated, the results obtained throughout the paper are in line with the theory in the field and thus prove the potential that this type of techniques have with regard to ionosphere sounding.