[gtfoutttt]

Assuming GP is talking RTK GNSS[0] it can be down to cm accurate with good techniques.

GNSS can technically get down to mm accuracy but that typically requires static sites with lots of data.

[0] https://en.m.wikipedia.org/wiki/Real-time_kinematic_position...

[jamesgasek]

sub-centimeter with RTK enabled. The device has an onboard cellular modem to receive atmospheric corrections