Comment Re:Better coverage through multiple systems (Score 1) 168
The problem isn't the GPS system. The problem is John Deere is trying to use the system at an accuracy (100% availability at 1m) greater than the specified [civilian] performance levels (95% availability at 7m).
While I can't speak as to the John Deere system in particular, most the Ag navigation systems are using WAAS on the low end and VRS RTK subscription systems on the high end.
Here in Ohio ODOT offers a reduced-fee reduced-accuracy VRS option for farmers, who don't need the sub-cm service.