Re: GBR21
- From: "Pieter Litchfield" <pvcl@*nospam*plitch.com>
- Date: Sat, 30 Sep 2006 12:55:17 GMT
Ahh - on a fishing boat we know 2 things - (1) weight and size aren't so
important, and (2) there is a well developed set of DGPS ground stations for
correction data locally along the coasts.
The GPS 120 is NOT a WAAS enabled GPS, the GPSMAP76CS IS WAAS enabled. You
may not be able to tell the difference in accuracy between the GPS 120 with
the GBR21 attached and working compared to the GPSMAP76CS when WAAS is in
use. The difference is a matter of a meter or two in position fix
calculation.
I'd suggest either is a good solution, and probably the accuracy differences
between them aren't terribly significant in your intended purpose.
"Rick" <fsholbrook@xxxxxxxxx> wrote in message
news:12hr4q565g07r24@xxxxxxxxxxxxxxxxxxxxx
Pieter Litchfield wrote:
If you have a GPS receiver with WAAS, and live in an area where WAAS isI was planning to use it on the west coast on my fishing boat. I have
available, the answer is "no - you don't need it." If you don't have a
WAAS capable GPS, then the answer is that a DGPS equipped receiver will
produce a smaller error that one no so equipped. The closer you are to
the transmitting base station, the better the result - in theory.
For years I hauled around a GBR21 with H-loop antenna and a Garmin 12xl
with external antenna (and a big battery) on a pack frame to map hiking
trail locations. It was great when SA was in effect, because it could
completely eliminate it. Big difference. When SA was dropped, it still
produced a significant difference from non-DGPS receivers. I was
working mainly within 20 miles of a DGPS base, so coverage was full time
and locally accurate. 100 miles away, it was easy to drop the DGPS
signal, and accuracy was not so good.
Today, I have a couple of handheld GPSs with WAAS. Why bother to haul
the pack full of equipment through the woods? I find my handhelds give
excellent reception under canopy, and WAAS corrections are constantly
available in my location and accurate.
Remember that WAAS is not avaialable world wide ( no details about use
given in your post).
"Dennis Pogson" <dennis_nospampogson@xxxxxxxxxxxx> wrote in message
news:1g7Tg.53093$G72.18058@xxxxxxxxxxxxxxxxxxxxxxx
Rick wrote:
I have a GBR21 DGPS beacon receiver I am wondering if I really needThe need for DGPS has receded considerably in the past 4-5 years but it
it I also have a GPSMAP76CS that appears to be almost as accurate as
the GBR21 is when hooked up to my GPS 120.
the question is do I need the GBR21?
is
still reckoned to improve postion accuracy over a non-DGPS receiver.
found that the GPSMAP76CS is almost as accurate but, the 120 is not as
accurate as the 76CS. thanks
--
Rick Holbrook
Fargo, ND
N 46.53.251
W 096.48.279
Having abandoned my search for truth.
I am now looking for a good fantasy.
.
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