Modern aspects of ionospheric propagation research

Ionospheric propagation research has seen substantial progress through (a) large capacity digital data storage, computing facilities and methods, (b) new satellite systems and receivers onboard satellites providing novel data sources. This paper concentrates on the possibilities gained with ionosphere tomography and satellite to satellite radio links. The improved information about the state of the ionosphere and the progress in ionospheric modelling brings advantages in all fields of application for radio wave propagation affected by the ionosphere, from classical to modern HF applications to applications of transionospheric propagation with signal frequencies from VHF to L band and higher.