From:
kgramp@csc.com
Sent: 1/23/2001 4:38:31 PM
To:
gpsstash@egroups.com
Cc:
Bcc:
Subject:

averaging a GPS position


Not wanting to be controversial, but I believe the averaging people
talk about doing when recording the lat/long of a cache is of little
use unless the averaging is for a long time, like 24hrs.

The reasoning behind this is that at any one time the GPS position
one gets is based on the current visible satellites and their position.
If you do averaging over say 10 minutes you will get a meaningless
accuracy of very small numbers like +/- 0.1m. That is the GPS position
is very stable over a short time.
The important number is the HDOP.

When someone goes to visit your cache they will more than likely be
seeing different satellites in different positions so will get a nice
stable
position but up to the HDOP from the actual position of the cache.

In some cases this may make the finding a cache difficult.

Karl.