Also, RTK is an interesting way to correct the signal to get sub-centimeter accuracy. Using the timing differences between satellites with a stationary unit and then sending the that to the rover is a cool workaround and can be used without expensive equipment now.
VRS RTK can even get 1cm RMS without needing a stationary unit. Just need atmospheric correction data for your approx location. Which has been amazing for outdoor mobile robotic applications.
They sell robotic lawn mowers with LIDAR and RTK GPS. LIDAR combined with RTK GPS is very neat because you can place every point in the point cloud on earth's surface.