Greetings,
there is a website, with public access, where you can subscribe, and recieve GPS information called NANUs, the website is managed by the US coast guard.
They are still launching satellites, big time, because, LEOs dont have a very long life time, especially when they use a lot of energy, to be kept on the ephemeris, and to transmit/receive GPS data.
Nevertheless you just need 5 satellites (baro aided capability, with RAIM handling Sat geometry as well) to do an RNAV RNP, RNP, NPA, GPS approach, with GPS as a primary sensor.
