We propose to characterize and develop a new technique that can open a new field: the GNSS-Astronomy. Indeed, a new low-cost, all-time, all-weather, all-sky, high-cadence technique proposed by the PI of this proposal (HP), the Blind Global Navigation Satellite System (GNSS) search of Extraterrestrial EUV Sources (BGEES, Hernandez-Pajares & Moreno-Borras 2020), has allowed the likely first detection and source location of stellar superflares with GNSS. The direct EUV rate measures might contribute to key questions in Astrobiology, like the Habitable Zone (HZ) for exoplanets near active M-type dwarf stars. And it should be considered that the stellar superflares might be more frequent than expected as it was shown for the Sun (Monte & HP, 2014, see bibliography in proposal). And now BGEES can be characterized, to monitor huge stellar flares, and in general the EUV signature of high energy explosions, by the first time in a 24/7 testbed feed with Near Real-Time (NRT) multi-frequency measurements of +130/+300 globally distributed multi-GNSS/GPS receivers in NRT/RT. BGEES is a new technique partially based on a scientific finding done by HP in 2012, which links the GNSS signal and the EUV flux rate of the external flare. The initial technique (GSFLAI, a.k.a. SOLERA), allows detecting strong, medium, and weak solar flares, according to direct measurements from spacecrafts. It was based on a simple first-principles-based model of the sudden over-ionization produced by them, in the very sensitive EUV range of 26-34~nm on the Earth's Ionosphere. Presently this technique is being continuously applied to monitor the solar flares in the SSA program (see Borries et al. 2020). Main reference (at the end of proposal) Hernandez-Pajares, M., & Moreno-Borras, D. (2020). Real-time detection, location and measurement of geoeffective stellar flares from Global Navigation Satellite System data: new technique and case studies. Space Weather, 18(3), https://doi.org/10.1029/2020SW002441
