МЕТОДЫ И АЛГОРИТМЫ ОЦЕНКИ ОСНОВНЫХ ПАРАМЕТРОВ МНОЖЕСТВА ПАРЦИАЛЬНЫХ КАНАЛОВ ИОНОСФЕРНОЙ КВ-СВЯЗИ ПРИ ЗОНДИРОВАНИИ ИХ СЛОЖНЫМ СИГНАЛОМ ТИПА FMCW
Authors: Иванов В.А. , Рябова Н.В. , Елсуков А.А. 
Published: February 2025

Рассмотрены вопросы моделирования ионосферного распространения КВ в рамках канальной модели. Представлены методики и алгоритмы оценки основных параметров ФРК при зондировании ионосферной линии КВ-связи сложным сигналом типа FMCW. Показано, что периодическое зондирование таким сигналом позволяет для каждого частотного канала определить профиль задержки мощности и отношение сигнал/шум. Развит метод оценки рассеяния по доплеровскому смещению частоты, который основан на использовании данных рассеяния во временной области. Развиты алгоритмы определения суточного хода параметров ФРК множества ионосферных каналов.

Introduction. The perspectives of short wave (HF) ionospheric communication are the long distance operation, relatively low cost in comparison with satellite communication, and fast recoverability. Due to these advantages, HF ionospheric communication is actively being developed, acquiring new modern qualities. The main achievements are due to the results of studying the ionosphere as a linear system based on the development of a channel model, as well as methods and facilities for radio channel sounding. The aim of the research was to develop methods, algorithms and facilities for experimental estimation of the main parameters of the ionospheric HF communication channel depending on the its average frequency. To achieve the goals, the following tasks were tackled: analysis of the issues of modeling HF ionospheric propagation within the framework of the channel model; development of methods and algorithms for estimating the main parameters of the CSF by means of sounding ionospheric HF communication link with the use of FMCW signal; development of a method for estimating Doppler spread with the use of data on delay spread; development of algorithms for measuring diurnal variations of the parameters of CSF of multiple ionospheric channels. Methods. The solution of the posed problems and the main scientific and practical results are based on the methods of mathematical analysis, computational mathematics, the theory of radio wave propagation in the ionosphere. The main theoretical results were verified by computational, laboratory and full-scale experiments. Findings. Studying the issues of HF propagation modeling within the framework of the channel model allowed us to develop methods and algorithms for estimating the main parameters of the CSF by sounding ionospheric HF communication link with the use of FMCW signal. It was shown that periodic sounding with such signal allows to determine the power delay profile and estimate the signal-to-noise ratio for each partial channel. The method for estimating Doppler spread was developed. It is based on the use of data on scattering in the time domain. Practical significance.Diurnal measurements of the signal-to-noise ratio were carried out for partial channels of the Cyprus-to-Yoshkar-Ola radio link. Experimental studies on the mid-latitude HF communication link showed that considerable attention should be paid to the influence of man-made interferences. It seems reasonable to study the interference spectrum in the HF range with the use of monitoring method. However, in this case, one should take into account diurnal variations of the scattering parameters and the signal-to-noise ratio, which can be detected by the method of periodic (with the scales of changes in ionospheric conditions) sounding of multiple channels when estimating SCF parameters.