[42938] in North American Network Operators' Group
RE: GPS SA and Network Timing
daemon@ATHENA.MIT.EDU (Ian A Finlay)
Wed Sep 26 10:05:30 2001
Date: Wed, 26 Sep 2001 10:03:02 -0400 (EDT)
From: Ian A Finlay <iaf@andrew.cmu.edu>
To: Eric Germann <ekgermann@cctec.com>
Cc: <nanog@merit.edu>
Message-ID: <Pine.GSO.4.33L-022.0109260956060.5008-100000@unix1.andrew.cmu.edu>
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Errors-To: owner-nanog-outgoing@merit.edu
Hello Eric,
I recently purchased a GPS. The manual indicates that SA has no effect on
timing. SA only affects positioning.
Actually, I just downloaded the latest firmware. They now have something
called WAAS (http://www.magellangps.com/press/general/pr010521waas.htm).
Quoting from that URL:
"WAAS, developed by the United States government, calculates errors in the
GPS signal then transmits correction messages to WAAS-capable GPS
receivers. Upgraded Magellan receivers provide higher accuracy, not only
from WAAS signals, but also when receiving correction signals from the
European Geostationary Navigation Overlay System (EGNOS), which covers
Europe. Additionally, projected specifications for the forthcoming
Multifunctional Transport Satellite-based Augmentation System (MSAS) for
Asia suggest that upgraded Magellan receivers will work with this system
as well. As a result, Magellan customers will gain better than three-meter
positioning accuracy throughout much of the world."
Regards,
Ian
