The DemoGRAPE system installed in the South African station SANAE IV between the end of December 2015 and the first days of January is already providing very interesting data. In particular, as noticed by the researchers of the upper atmospheric group of INGV (Istituto Nazionale di Geofisica e Vulcanologia), coordinators of the project, two important geo-magnetic storms already took place over Antarctica in the last month.
The Septentrio PolaRxS PRO GNSS receiver was able to identify a moderate ionospheric activity during both events. The 4tuNe GNSS bit grabber, coupled with a software receiver, was operational only during the second storm, and automatically collected some GNSS raw IF data, thanks to the automatic triggering, as expected. Unfortunately we still have no access to the raw data in our lab, but we were able to analyse them by remotely post-processing them.
As a first preliminary result, figure 1 depicts the phase scintillation for GPS PRN 7, during a few hours on January 21, as computed by our software receiver, compared with the same index computed by the Septentrio professional receiver. From the figure we can clearly see that the Phi60 index passes the threshold, fixed equal to 0.4, and thus enabling the saving of the raw data on an eternal hard drive, for further analysis in our lab.
Similarly, figure 2 reports the phase scintillation index for several satellites, as computed by the 4tuNe GNSS bit grabber on January 20. Also in this case a moderate ionospheric activity is revealed.
It is well known that, geomagnetic storm over Antarctica, generate mainly perturbations in the signal phase, rather than in the signal amplitude, as in equatorial regions. These results further confirm the thesis.
More info on our FROZEN NAVSAS BLOG.