Real-time Kinematic GPS (RTK-GPS) [1], available from Sparkfun for $200 [2] (and cheaper elsewhere), gets you centimeter accurate positioning in the US and most

Real-time Kinematic GPS (RTK-GPS) [1], available from Sparkfun for $200 [2] (and cheaper elsewhere), gets you centimeter accurate positioning in the US and most other countries. [1] https://en.wikipedia.org/wiki/Real-time_kinematic https://en.wikipedia.org/wiki/Real-time_kinematic [2] https://learn.sparkfun.com/tutorials/what-is-gps-rtk/all https://learn.sparkfun.com/tutorials/what-is-gps-rtk/all