Re: Differential GPS

> Interesting stuff.  They are talking about 3-D
> accuracy to a meter and with a DGPS unit at the
> airport you are going getting the error to less than a
> centimeter at touchdown.

probably have mutiple transmitters arrayed around the area (on hills and
towers etc.) - but they still don't land using GPS - nor would I want to
do
so with the degree of variability you can get from even a DGPS unit from
second to second - did you know that Europe has their own series of GPS
satellites? EGNOS is due to be online in 2003 and promises and accuracy
of 9
metres 95% ofthe time (still want to use this for anything precise) -
the
WAAS and EGNOS netorks are good, DGPS helps greatly at close range but
the
system become truely cool when you have the latest satellite
co-ordinates
and the lag time decryption codes :_)

> I will be happy to see it as some approaches into the
> fog to get home have been quite dicey.  50 ft hover
> with no ground in site!

Yup and a ground controller with a bleeding ulcer and a substance abuse
problem telling him to ignore the GPS and follow the route on screen -
"what
mountain? don't you trust me? Listen I've been doingthis for years? no -
I'm
not bitterand twisted..."
 Paranoia notwithstanding GPS is cool and make my life easier and your
life
safer but practical experience demand we avoid as much industry
"information" as possible - they're not always giving us the whole
story.

Brendan