Ionosphere as a Medium of Radio Wave Propagation in Different Applied Tasks

It is known that one of the main problem in solving applied radiophysical tasks of radiolocation and radio direction finding is the lack of complete information about the medium of radio waves propagation. The aim of the paper is to discuss the different aspects of this problem such as the difficulties encountered in creating and testing climate models of the ionosphere, as well as many different data assimilation. Particular attention is paid to the causes of existing problems and the inevitable need of space weather monitoring for the correct solution of various applied tasks.