Technique of ionospheric parameters automatic determination from data of vertical sounding with a continuous chirp signal

We present a technique for determination of ionospheric parameters based on automatic interpretation of vertical sounding (VS) ionograms. Ionograms are interpreted using points with significant amplitude, which were detected after secondary data processing with results of modelling of VS signal height-frequency characteristic (HFC). We have developed algorithms to extract HFC tracks of signals reflected from the E, F1, and F2 layers. These algorithms involve analyzing signal amplitude characteristics and plotting distribution histograms of points falling into the HFC model mask when it is moved over the ionogram. The algorithm to detect tracks of signals reflected from sporadic layers is implemented separately. From the resultant VS HFC, we can estimate ionospheric parameters and calculate the electron density profile.