The article is devoted to the problem of forecasting the state of the ionosphere for processing single-frequency GNSS measurements. The problem of GLONASS signals with frequency division, for which there is no ionospheric model, is described. To calculate the total electron content of the ionosphere, a model of the ionosphere is built based on the spherical decomposition coefficients. Since the state of the ionosphere depends on solar activity, the dependences of the leading coefficients of the spherical decomposition of the ionospheric TEC on the solar activity index F₁0. 7 are given. It is shown that the behavior of these coefficients is well described by this index, respectively, good forecasting mechanisms for this index will improve the accuracy of processing single-frequency GLONASS measurements.
Trofimov et al. (Mon,) studied this question.