Does simpleRTK2B requires ground station?

Might sound stupid but I don’t get my head around the ground station part of the gps. Do I necessarily need a ground station and if yes wich one to choose?
Again I am going to use ardusimple simpleRTK2B with the ublox antenna.

You can get rtk with one receiver via ntrip, providing you have an internet connection and are within 150km of a base station.

Thank you very much!