Highlights of ionospheric investigations at Comandante Ferraz Brazilian Antarctic Station

The ionospheric investigations have improved our understanding of the space weather role in the upper atmosphere conditions, particularly at higher latitudes where the geospace phenomena print their signatures. The simultaneous observations using multi-instruments have improved our knowledge of the coupling processes inside the ionosphere, and their connection with the magnetosphere and neutral atmosphere processes under the space weather phenomena. The ionosphere probing at EACF started on 1986 using an analogical very low frequency (VLF) system, and after the year 2004 using digital VLF system, global navigation satellite system (GNSS), riometers and Canadian digital ionosonde (CADI). This paper presents the different radio techniques that have been used at Brazilian Antarctic Station Comandante Ferraz (EACF) to characterize the ionospheric conditions, and the highlights of the studies using multi-instrument observations performed in the last few decades.