Date: Thu, 4 May 2000 16:02:13 -0600 (MDT) From: Nate Williams <nate@yogotech.com> To: Warner Losh <imp@village.org> Cc: nate@yogotech.com (Nate Williams), hackers@FreeBSD.ORG Subject: Re: GPS heads up Message-ID: <200005042202.QAA09181@nomad.yogotech.com> In-Reply-To: <200005042156.PAA43697@harmony.village.org> References: <200005041411.IAA17374@nomad.yogotech.com> <2288.957418565@critter.freebsd.dk> <200005040801.BAA67715@apollo.backplane.com> <200005042156.PAA43697@harmony.village.org>
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> : That's very different from what the GPS experts at SRI tell me. They > : start to average things out in a matter of hours, and within a week can > : have it almost gone. However, they're also using multiple satellites, > : which allows them to more quickly find the center. > > The experts here tell me that professional surveyers get sub meter > accuracy with in about an hour with commercially available hardware. > This was with SA. That's more in line with what my 'expert' friends have told me as well. ~24 hours to get 1 cm accuracy with tweaked gear with SA enabled. > He estimates that now it would take about 6-10 > minutes to do the same thing since SA is turned off. Wow, that's even faster than I thought it would take, since you've still got ionosphere noise, which is harder to 'average out'. In any case, this discussion has been a refreshing and enjoyable change from some of the others on the mailing lists. :) Nate To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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