The GPS/GNSS module used in the Rock Seven devices (RockAIR, RockFLEET, RockSTAR) is the NEO-M8 from u-blox.

The module automatically uses both GPS and GNSS, with no operator intervention required. 

The accuracy of this module in optimal conditions (civilian commercial SA, good view of the sky) is 2.5m with no local area augmentation.

The manufacturer's datasheet is attached to this article.