Space and time statistical data processing in HF ionospheric sounding

The paper describes spectral and correlation processing of the HF radio signals scattered by small scale ionospheric inhomogeneities (5 to 50 m in size). The measurements at frequencies above MUF were performed on single-hop midlatitude propagation paths. The probing signals from suitable broadcasting stations were received with small size dipole antennas and a highly directional large array, and were used to analyze azimuthal and elevation-angle scattering patterns, space, time and frequency correlation functions and Doppler shift spectra. Comparison with a theoretical model allowed restoring a number of ionospheric statistical parameters, including the power spectrum of anisotropic electron density fluctuations and plasma drift velocities