RE: GPS SA and Network Timing
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
Unnamed Administration sources reported that Ian A Finlay said:
I recently purchased a GPS. The manual indicates that SA has no effect on timing. SA only affects positioning.
Err... GPS is nothing but timing. I'm not quite sure how you'd change "position" without timing. Position is a function of time measurments...and a bunchamath. -- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
On Wed, 26 Sep 2001 21:39:37 EDT, David Lesher <wb8foz@nrk.com> said:
GPS is nothing but timing.
I'm not quite sure how you'd change "position" without timing. Position is a function of time measurments...and a bunchamath.
The vast majority of people will not notice that their clocks are 400 nanoseconds off. What are they going to check against? The vast majority of people WILL notice if they hit the concrete wall that's 400 feet past the highway exit. That's VERY easy to check against. Valdis Kletnieks Operating Systems Analyst Virginia Tech
Date: Wed, 26 Sep 2001 21:39:37 -0400 (EDT) From: David Lesher <wb8foz@nrk.com>
GPS is nothing but timing.
I'm not quite sure how you'd change "position" without timing. Position is a function of time measurments...and a bunchamath.
Of course, the Heisenberg Uncertainty Principle states (among other things) that "the more precisely position is determined, the less precisely the momentum is known". As long as we're getting technical, shall we add quantum mechanics to the discussion? ;-) (I suppose that GPS breaks down as we approach the speed of light...) Eddy --------------------------------------------------------------------------- Brotsman & Dreger, Inc. - EverQuick Internet Division Phone: +1 (316) 794-8922 Wichita/(Inter)national Phone: +1 (785) 865-5885 Lawrence ---------------------------------------------------------------------------
participants (4)
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David Lesher -
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Valdis.Kletnieks＠vt.edu