Electromagnetic sounding technique using spectral and spatial sampling of the reception signals, application to the study of inhomogeneities in ionospheric plasma

The study of diffusion properties of ionospheric plasma was connected to inhomogeneities of free electrons density. The inhomogeneous studies were carried out by different methods, using very sensitive measuring systems. The backscatter sounding method necessitated important installations. A sounding station, using this principle, was constructed. Very accurate and precise measurements were readily obtained. Frequency resolutions better than 0,01 Hz are usually reached although measurements points are separated by only 0,05 s. Spatial resolutions were only limited by technological aspects. This technique was used in backscatter ionospheric soundings and allowed low value inhomogeneities in ionospheric plasma to be revealed, as well as certain brief local changes such as ionized meteor trails.