A propagation model for geolocating ionospheric irregularities along radio occultation ray-paths

We have developed a new propagation modeling technique for characterizing and geolocating ionospheric irregularities using radio occultation observations of amplitude scintillation. The approach taken is to solve an inverse problem for the propagation of radio waves through a phase changing screen. Referred to as Irregularity Parameter Estimation (IPE), this inverse technique infers the irregularity turbulence strength, spectral index, and Fresnel frequency from measurements of amplitude scintillation. A geometric model for the effective velocity at which the radio occultation ray path scans through the irregularity region is used to map the Fresnel frequency to Fresnel spatial scale, which yields the distance from the receiver to the irregularities. We demonstrate the approach by geolocating irregularities observed by the CORISS instrument onboard the C/NOFS satellite.