Wayne.B wrote:

On Thu, 24 Feb 2005 23:20:22 GMT, Rich Hampel
wrote:

there was a general 'roll-over' for GPS receivers just after Y2K that
required sofware / e-prom, etc. changes to keep them 100% compatible
with the international system. You should ckeck to see if this was
done (or not) on this unit.

There was the 1024-week rollover of GPS time which happened in August
of 1999. But the unit in question locked onto satellites and
apparently came up with the correct position and date/time, in which
case it handled the roll-over correctly.

If not then the unit would not be totally
realiable with the worldwide system upgrade.

If it gave correct position and date/time when it locked on then
the rollover was handled correctly and there shouldn't be any
concern about that issue.

That's true but for me the real issue would be lack of WAAS
capability. WAAS has increased average accuracy of GPS positions from
+/- 100 yards down to about 15 yards.

No, accuracy had already improved from a nominal 100m to 15m when
Selective Availability was turned off in May, 2000. Actual measurements
have shown the 95% accuracy to be closer to 7m without WAAS capability.

WAAS further improved the 95% accuracy in areas that are covered to
about 3m.

That is a REALLY significant
improvement, and is now frequently more accurate than the charts.

Even without WAAS the accuracy is frequently better than that of the
charts, so WAAS is mainly of benefit when going back to a place
where you've already taken (or been given) GPS positions.

If
you doubt the significance, take a look at the number of channels and
inlets that are less than 200 yards wide, or take a close look at your
visible range in heavy fog or rain.