When we talk about satellite navigation, people usually associate it with "only" GPS. However, there are multiple GNSS systems deployed and modern smartphones, for example, can utilize different GNSS constellations. There are American GPS, Russian Glonass, Chinese BeiDou and the forthcoming European Galileo.
I'm curious, does anyone know how the avionics in typical modern airliner actually use the satellite navigation? Is it only GPS or a combination of all systems, or only some of those? I mean If only GPS is jammed, does the system notice this and switch over, or prefer one over another?