Ionospheric Scintillations of Satellite Signals

The scintillation of satellite-emitted radio signals has been observed using two different techniques, namely, Doppler-shift frequency measurements and radio direction finding. In this shortened version of our complete paper, there are given the results obtained using Doppler-shift measurements only. Variations from a smooth Doppler-shift curve obtained during individual orbits give a measure of the frequency scintillation occurring and thus of the roughness of the ionospheric path between the satellite and the observer. As expected, these variations are a function of frequency, and they become less as the frequency is increased.