Structure and variations of the south-polar ionosphere by GNSS-tomography

The paper is devoted to determination of the total electron content in the vicinity of the South geomagnetic pole using observations by global navigation satellite systems. Observations were carried out at the Russian Antarctic station Vostok in the periods February 2016 - January 2017, February 2018 - February 2019 and February 2020 - January 2021. Observations were made with satellites of GPS and GLONASS systems. Processing of observations was carried out by use of the TEC-suite software. Total electron content series were obtained for the specified time periods. Our results were compared with those of Center for Orbit Determination in Europe, there is a good agreement, based on which we conclude that our data are reliable. For all periods of observation, average daily profiles of changes in the total electron content in winter and summer were plotted. An excess of the winter total electron content measured from global navigation satellite systems observations over the model data provided by Center for Orbit Determination in Europe by about 5 total electron content unit was noted.