If the rubber factory takes a day off, the truck in the field can still drive.
etc, etc.
Can't talk to a specific single space computer with no fallback? truck in the field might as well be a potato.
...All of which seems a little silly in comparison to setting up some solar powered, battery backuped wireless radios/beacons, and establishing a localized coordinate grid, no extraterrestrial equipment required.
Or is cutting out a tractors width of field around all beacons enough to render a farmer uncompetitive as well?
I just resent the implication that just because we have GPS satellites, that those are the only form factor such a solution can take. I always saw satellite GPS as A) a quick global win for the public and B) sort of an incentive to keep iterating on rocketry in parallel with establishing similar terrestrial nav gridding.
I don't think it is wise to just not establish terrestrial nav grids because GPS. Always, always, always build redundancies.