NEURAL NETWORK-BASED PREDICTION MODEL FOR THE DYNAMICS OF THE IONOSPHERIC EQUATORIAL ANOMALY USING THE TOTAL ELECTRONIC CONTENT

In this paper we present the prediction model for the dynamics of the ionospheric equatorial anomaly that is based on the use of the Principal Component Analysis (PCA) and Artificial Neural Networks (ANN). The prediction model was developed by using global maps of the ionosphere Total Electronic Content (TEC) for the period from 2001 to 2018. We show that in case of correct data centering and elimination of diurnal and seasonal factors, the equatorial anomaly makes major contribution to the variance of fluctuations in the TEC data. We applied several neural network-based prediction models that were trained independently for each component of the decomposition. The approach based on a hybrid model consisting of a convolution network and a network with long short-term memory with preanalysis of the principal components reduced the prediction error of TEC maps by 2 hours. The prediction error of this model was 4 times less than the error of the linear regression model.

Development of differential correction of coordinate-time and consumer navigation support based on trajectory data comparisons

The article deals with the use of the results of measuring the catalogued space objects coordinates by a radar station for long-range detection in the interests of differential correction of coordinate-time and navigation support for consumers. We describe the idea of comparing trajectory data that allows us to calculate the total electronic content in the direction of a catalyzed space object under the assumption of a thin layer at the height of the ionosphere maximum. The main stages of the method of differential correction of coordinates-but-time and navigation support for consumers based on the results of comparing trajectory data are described. The results of modeling are presented, which allow us to evaluate the possible positive effect when using the proposed approach.

Meteorological Storm Influence on the Ionosphere Parameters

This paper presents the observations of ionospheric parameters in Kaliningrad (54° N, 20° E) during a meteorological storm in the Baltic Sea during October 2017 and 2018. Analysis of the total electronic content (TEC) during the storm showed that perturbations of the TEC values from the median can reach two standard deviations of the value. For the critical frequency of the F2 layer, it was 1.5–1.6 times the standard deviations. On days of a meteorological storm, significant changes were noted in the dynamics of the E-layer’s critical frequency. The reasons for the occurrence of the observed phenomena were due to the propagation of acoustic-gravity waves generated by convective processes in the lower atmosphere during periods of a meteorological storm. Spectral analysis of TEC variations revealed an increase in the amplitudes of ionospheric variations 10–16 min over the area of a meteorological storm. The analysis allowed us to conclude that ionospheric perturbations during the meteorological perturbation were caused by increased acoustic-gravity wave (AGW) generation processes in the lower atmosphere. The most likely cause of negative ionospheric disturbances were processes associated with the dissipation of AGW propagating from the area of a meteorological storm and increased turbulence in the lower thermosphere.

Responses to the preparation of strong Kamchatka earth-quakes in the lithosphere–atmosphere–ionosphere system, based on new data from integrated ground and iono-spheric monitoring

The experience of short-term forecasting of Kamchatka earthquakes based on complex well measurements at the Petropavlovsk-Kamchatsky geody-namic polygon (PGP) shows that, as a rule, the preparation of strong Kamchatka earthquakes is fairly reliable in the medium-term time scale (months or years be-fore the earthquake). However the determination of the stage beginning imme-diately preceding an earthquake (weeks or days before the main event) is a very difficult task. At present time, the solution of this problem is largely associated with the involvement in the preparation of forecast conclusions of data from continuous monitoring of the ionosphere, carried out by ground-based means of vertical radiosonding and measurements of total electronic content (TEC) using the global navigation satellite system GLONASS and GPS. This is due to the fact that significant changes in a number of ionospheric parameters occur mainly 1-5 days before the Kamchatka earthquakes. The results of the compar-ison of the data of daily monitoring of the ionosphere, including information on TEC, with the data integrated downhole measurements showed a rather high correlation of occurrence of anomalies in the ionosphere before strong earth-quakes with changes in the complex parameters in borehole measurements. As one example, the report presents the results of ionospheric and borehole monitoring obtained in the time neighborhood of the strong (MW = 7.5) the earth-quake that occurred on March 25, 2020 in the area of the Northern Kurils. The results show a high correlation between changes in the specific electrical resis-tivity of the Geospace in the area of the PGP with variations in the TEC and the formation of a number of other anomalies in the ionosphere a few days be-fore the earthquake. These results indicate that it is possible to determine fairly reliably the beginning of the final stage of preparation for a strong earthquake. Currently, methods based on atmospheric parameters monitoring are used quite successfully for predictive estimates of the epicenter and magnitude of an earth-quake: the method of chemical potential corrections for measurements at an altitude of ∼ 100 m, as well as data from measurements of outgoing long-wave infrared radiation (OLR) at the level of the upper edge of clouds (heights of 10 -15 km).

Ionospheric effects of two solar flares in the maximum of solar cycle 23 and in the minimum of solar cycle 24

Using data from the GPS and GLONASS navigation satellite systems, we analyze the responses of the mid-latitude ionosphere to the extreme solar flares that occurred at the maximum of solar cycle 23 (October 28, 2003) and at the minimum of solar cycle 24 (September 6, 2017) during the same season at close solar zenith angles. To obtain the response, we use the rate of change of the total electronic content, which is practically independent of characteristics of equipment and is determined only by parameters of a propagation medium (the ionosphere in our case). The ionospheric response is shown to be almost independent of the total duration of the flare. In both cases, the duration of the main response at a level of 0.5 is about 1.5–2 min, whereas the total duration of the response is about 10 min and fairly independent of solar flare importance.

Ionospheric effects of two solar flares in the maximum of solar cycle 23 and in the minimum of solar cycle 24

Using data from the GPS and GLONASS navigation satellite systems, we analyze the responses of the mid-latitude ionosphere to the extreme solar flares that occurred at the maximum of solar cycle 23 (October 28, 2003) and at the minimum of solar cycle 24 (September 6, 2017) during the same season at close solar zenith angles. To obtain the response, we use the rate of change of the total electronic content, which is practically independent of characteristics of equipment and is determined only by parameters of a propagation medium (the ionosphere in our case). The ionospheric response is shown to be almost independent of the total duration of the flare. In both cases, the duration of the main response at a level of 0.5 is about 1.5–2 min, whereas the total duration of the response is about 10 min and fairly independent of solar flare importance.

Solving a navigation problem with the total electron content model GEMTEC

This article explores the possibility of improving the accuracy of positioning in single-frequency satellite radio navigation equipment through the use of an empirical model of the total electronic content GEMTEC. The effectiveness of this model is compared with that of the Klobuchar model, which is recommended for the GPS interface control document. We conducted testing at our observation points, using data from the international network of IGS stations in the GPS system. The use of the international network allowed us to select a long period of time for the testing from 2001 to 2017. As a result, it was shown that the GEMTEC model significantly reduces the average positioning errors as compared to the Klobuchar model. We also demonstrate the possibility of introducing the GEMTEC model and its full-featured use in single-frequency home-class receivers, for example, in the Russian receiver MNP-M7.

Solving a navigation problem with the total electron content model GEMTEC

This article explores the possibility of improving the accuracy of positioning in single-frequency satellite radio navigation equipment through the use of an empirical model of the total electronic content GEMTEC. The effectiveness of this model is compared with that of the Klobuchar model, which is recommended for the GPS interface control document. We conducted testing at our observation points, using data from the international network of IGS stations in the GPS system. The use of the international network allowed us to select a long period of time for the testing from 2001 to 2017. As a result, it was shown that the GEMTEC model significantly reduces the average positioning errors as compared to the Klobuchar model. We also demonstrate the possibility of introducing the GEMTEC model and its full-featured use in single-frequency home-class receivers, for example, in the Russian receiver MNP-M7.