Both are Differential Global Positioning System (DGPS). There are a large
number of ways to get the correcting signals. Nothing changes the fact that
they are the same technique implemented by two different communication
paths. You can also do differential by modulation of the LORAN signal as is
done in Europe. You can also use a local reference by short wave. It is
all differential.

WAAS is a little more sophisticated but the basics are the same.

Try it this way...if the differential signal from a USCG site was forwarded
to you by a satellite...say via Iridium...would it cease to be DGPS and turn
into WAAS? No I don't think so.

I also suggest that "Me" not comment until the question is understood.
"Bzzzt Wrong Answer"

Jim Donohue
"Me" wrote in message
...
In article paPwd.83$iD.50@fed1read05,
"Jim Donohue" wrote:

Actually WAAS is DGPS...Jim

Bzzzt Wrong answer. Would you like to try for what is behind Door #3?

WAAS is a SAT based Service, whereas DGPS is a MF Terrestrial based
Service. Two different things that try to correct the same GPS
accuracy.


Me