On Thu, 22 Dec 2011 20:43:43 -0500, JustWait
wrote:

On 12/22/2011 8:09 PM, Wayne.B wrote:
On Thu, 22 Dec 2011 18:46:22 -0500, JustWait
wrote:

On 12/22/2011 6:11 PM, Wayne.B wrote:
On Thu, 22 Dec 2011 16:18:38 -0000, "Alisdair Gurney"
wrote:

It seems to me real sailors needn't be concerned about this at all. Who
needs GPS inland or very near coastal anyway where landmarks and
navigation marks are eyeball visible?

.. sorry, but I have to agree with this view.

======

Not really. A lot of navigation is done in coastal waterways and
inland rivers, some of it at night or in reduced visibility.

It turns out that one of the best connected opponents to the proposed
Lightspeed service is tractor manufacturer, John Deere. Apparently a
lot of new farm tractors are equipped with precision GPS units for the
purpose of accurate seed planting and other hi tech applications.


Been going on for a long time. GPS grids are running tractors, plowing,
planting, and working millions of acres with no drivers...

===

Holy cannoli ! Robotic tractors? Hope none of them have been
drinking and plowing a wide furrow. :-)


Well, I think they must use something to aid the GPS because iirc the
tolerance of GPS is +/- 30 feet or something like that...


One can get accuracy to 3 ft, and even to 6 inches. Just have to throw
money at it.

Years ago, before GPS, my company did a custom radio control for a
local cane farmer's tractor, with all the necessary failsafes. He
would drive the harvester and the R/C tractor with a fifth wheel
trailer alongside. When the trailer was full, he'd drive the tractor
to the pickup site, disconnect and hook on an empty and continue.

He was able to stack 'um up for the trucks to pick up all by himself.

Rick