The Global Ionospheric Flare Detection System (GIFDS) of the DLR consists of a ground-based network of VLF receivers (Perseus SDR - Software Defined Radio), which provides amplitude and phase measurements at multiple frequency channels from 10 to 60 kHz. One of the main objectives of GIFDS is the immediate and continuous detection of solar flares as a result of their impact on the bottomside ionosphere and consequently their sudden effects on VLF signals. In general, these measurements are determined by solar irradiation and geophysical conditions. The influence of diurnal variations on VLF amplitudes can be corrected by applying time series analysis followed by detrending. The VLF data is regularly adjusted by various transformation techniques to ensure a stabilized output. Finally, the results are compared with the X-ray flux obtained from GOES satellites to validate the magnitude and shape of flares recorded by GIFDS. As solar events can only be detected during daytime, DLR has been installing a uniform array of receivers at selected locations around the globe. Measurements carried out at the dayside part of the Earth will be provided 24/7 in the near future.
On our systems, a new modular software defined radio program will run, allowing to add or change recorded frequencies. This is the base for direct evaluation algorithms for detecting flares in real time. The raw measurements will be released periodically to a central managed storage, allowing easy uniform access and database search. The high-level warning information shall be transferred continuously in order to enable raising alerts.
GIFDS is part of the International Space Weather Initiative (ISWI).
