It uses GNSS and carrier phase DGPS to get centimeter level accuracy. You do not need to setup base stations with this method as you would with RTK. From there spec sheet in the link the OP provided there are several levels of precision available: meter and submeter use Satelite based corrections and Decimeter and Precision use real-time post processing.
- Meter -Worldwide with data connection; in most of the world via RTX Satellite delivered corrections
- SubMeter - Worldwide with data connection; in most of the world via
RTX Satellite delivered corrections
- Decimeter - Data connection required.
- Precision - Data connection required.