Re: A strange problem with my GPS receiver

From: Stan Gosnell (fakename_at_fakeaddress.com)
Date: 06/20/04 

Date: 20 Jun 2004 16:14:54 GMT

"Zeldus" <no@mail.com> wrote in news:40d538e7$0$282$626a14ce@news.free.fr:

>
> I've been to Royal Observatory of Greenwich, near London with my Garmin
> emap and I have watched my position just on the famous meridian (wich is
> marked on the ground) and there, surprise: I had a given precision of
> 5,7 meters by the receiver and I've noticed a real error about 130
> meters with the precise position of the Observatory (which is noticed on
> the wall of it). My receiver seems to be OK and I'm sure the Greewich
> meridian is at the right place in the garden of the Observatory :-) So,
> where is the problem ?

The problem is that WGS84 wasn't used to set the prime meridian. That was
done before the precise shape of the earth was known. Using different datums
will give different locations. Don't expect the Brits to change things to
conform to WGS84, even though that's the most precise datum extant. 

-- 
Regards,
Stan