Yes, that's a big problem. The gps outputs in the format 1234.5678, 12 is degrees, 34 is minutes, and 5678 are fractional seconds (multiply by 60 to get number of seconds, we instead just converted our coordinates to this format for ease of programming)
In our location our dimensional accuracy is approximately +/- 3 ft east/west and +/- 6 ft north/south WITHOUT calibration.
By calibrating it you can actually get it down to about +/-2 ft for both. This is pretty vital because some of the golf paths are as thin as 5 feet wide with dangers of hitting a tree or driving into a hazard on either side.
This is for conceptual design, it's likely it will never actually be patented or sold but it will be functional.