How can I identify GPS sattelites in TinyGPS++?
There is a bug in TinyGPS++ as it only counts GPS satellites. See https://github.com/mikalhart/TinyGPSPlus/issues/52 

PRN numbers are used to identify satellites:


  GPS = 1 to 32
  
  SBAS = 33 to 64 (add 87 for PRN number)
  
  GLO = 65 to 96