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Description
The ionosphere affects trans-ionospheric radio signals even at GHz frequencies and in the bands that are used for satellite based positioning and navigation. Density measurements by Langmuir probes on the Swarm satellites at altitudes between about 450 and 510 km can be used to roughly characterize the total effects on GNSS signals during a period of about 12 years since the Swarm launch. Comparison with data from SWEPOS system and scintillation receivers on the ground reveals both, a ionospheric delay which is largest in the hours before and after local noon and seen at all latitudes over Sweden, as well as irregular disturbances which are normally seen in the Northern parts of Sweden in the night, but expand to the south of Sweden and beyond in the large geomagnetic storms which have occurred around the most recent solar maximum.
