|
|
(no email)
Date: Fri Oct 14 2005 - 01:48:31 EDT
You should leave the altitude function off if that option is available. It
requires one more satellite signal to compute altitude which can slow the
response and can reduce accuracy on your position calculations.
If you think of the satellite signals intersecting horizontally from
multiple sources and compare it to the old sextant plots you can see that
you should get a small center of probable location. But when you plot all
the vertical signals descending on your antenna you can see that the angles
between them are all within say a 90 degree window rather than the 360
degrees for horizontal location. So with the narrow angles available for
vertical resolution, the intersection errors can cause significant altitude
errors just like the Loran locations would get hairy when the loran signals
were nearly parallel (for those that remember LORAN).
Regards,
Andina Marie Foster,
----- Original Message -----
From: "Rosalie B." <>
To: <>
Sent: Thursday, October 13, 2005 12:55 PM
Subject: lv-ab: Error in altitude was Re: Heading info from GPS
> On Thu, 13 Oct 2005 15:37:00 +0000, you wrote:
> I've never been able to get our GPS to read altitude at all reliably,
> even when I've followed the directions and I've stopped trying. It
> either says we are at 200 feet or that we are underwater. Is this at
> all important?
>
> SNIP >>
>
> grandma Rosalie
>
___________________________________________________________________________
|| The Live-Aboard List : send a "subscribe" or "unsubscribe" request ||
|| in body of message to: ||
|