One of our customers is building wonderful things with the RasPiGNSS. Ingmar Stapel builds robot cars based on the Raspberry Pi and the RasPiGNSS. For precise navigation two RasPiGNSS are used in RTK mode, one set up as a fixed base station, while the other one is mounted on the robot car (rover), using RTKLIB to compute a precise RTK GNSS solution. The setup and installation of hardware and software is explained in detail at custom-build-robots.com/elektronik/praezise-gnss-positionierung-mit-dem-raspberry-pi-und-rtklib-einfuehrung (in German). Check out his website at custom-build-robots.com for more information!