Две методики измерения aмплитудно-частотных характеристик многолучевых ионосферных коротковолновых радиолиний по данным наклонного радиозондирования ионосферы

Abstract

Two methods of measuring the amplitude-frequency characteristics of multipath ionospheric shortwave radio channels with high frequency resolution (tens-hundreds of hertz) are presented. Since traditional narrow-band channels do not allow to separate the various modes of ionospheric propagation of short waves interfering with each other, it is proposed in this paper to use broadband signals, which makes it possible to separate the received modes of ionospheric propagation of a radio signal, as well as to distinguish the signal from interference. The advantage of the first technique is that, together with the amplitude-frequency characteristic of the radio line, as a result, the mode pattern of multipath propagation of short waves becomes known, which allows us to draw qualitative conclusions about the propagation of radio waves, as well as to apply classifications according to empirical multipath models. Disadvantages of the first technique: the manual stage of the selection of mode tracks on the ionograms of oblique sensing, as well as the loss of some information about the energy of the mode tracks due to the diffuseness (blurring) of the traces of mode tracks on the ionogram. The second method, on the contrary, gives only an estimate of the amplitude-frequency characteristics of a multipath shortwave radio line without revealing the mode pattern of multipath, but does it automatically and without losing information about the energy of diffuse tracks. The presentation of both methods in one article allows you to indicate the advantages and disadvantages of each of them, and, accordingly, the preferred areas of application. Since it is important to have a set of techniques with an integrated system approach to the study and measurement of the characteristics of the ionosphere and ionospheric radio channels.