Date: Thu, 04 May 2000 00:41:33 -0700 From: Kent Stewart <kstewart@3-cities.com> To: Mike Nowlin <mike@argos.org> Cc: Wes Peters <wes@softweyr.com>, Warner Losh <imp@village.org>, Matthew Dillon <dillon@apollo.backplane.com>, hackers@FreeBSD.ORG Subject: Re: GPS heads up Message-ID: <391129AD.3050461@3-cities.com> References: <Pine.LNX.4.05.10005040321200.4046-100000@jason.argos.org>
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Mike Nowlin wrote: > > > This is what "Differential GPS" provides: a standard time source that > > can be used to remove the SA meanderings from the GPS fix. > > If I'm understanding this correctly (with very little actual research into > it) is that a DGPS station essentially transmits the difference between > what it "hears" as it's location and what it's actual measured location > is to the clients, which apply this change to their local "heard" > position. (Assuming that both sides are within the appropriate range of > each other that allows them to hear the same satellites.) > > Do I have it about right? > > (I just hooked up my Garmin GPS-20 and my Delorme Tripmate again to my > "figure out what the differences are between these two GPS units are and > plot them on the screen" program -- it'll be interesting to compare the > results from now and 6 months ago...) > > Out of curiosity, how many people in this discussion are hams? > > --mike N8NVW > > (Funny how the GPS changes are two weeks after the FCC Part 97 licensing > changes took place... I wonder if there's any (even remote) > connection...) I think there is one or more GPS systems up there. When you have the only one, you can introduce side effects like that and they matter. When someone else has one, it doesn't matter that much any more. IIRC Russia was starting to put one up more than a year ago. If we don't think it matters anymore, than one of them is operational. Kent - ka7gkw > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message -- Kent Stewart Richland, WA mailto:kstewart@3-cities.com http://www.3-cities.com/~kstewart/index.html FreeBSD News http://daily.daemonnews.org/ SETI(Search for Extraterrestrial Intelligence) @ HOME http://setiathome.ssl.berkeley.edu/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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