I am new and I have a question regarding these corrections, I had understood that to correct it was necessary to read the emlid, CORS data and NASA ephemerides. In the Emlid Studio it only asks for the EMLID data and the CORS data, in the Emlid Studio result I got 2mm of error (the reading was 7 hours).
will it be enough?
The ephemeris data (GPS/GLONNAS… ) are found in the reach .P data and are from transmitted orbit.
Nasa ephemeris data is orbit accurate (Sometimes may be relevant, depending on your project). But with transmitted orbit data you also have good accuracy for topography.
I can see that @jose.oro already answered your questions. I can only add that the time of observations depends mainly on the sky view conditions. We recommend logging static data for an hour if you use PPK with CORS data and at least 4 hours in case of the PPP option.
Regarding your case, 7 hours of logging is more than enough for PPK.