From owner-freebsd-hackers Wed May 3 13: 8:52 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from orion.ac.hmc.edu (Orion.AC.HMC.Edu [134.173.32.20]) by hub.freebsd.org (Postfix) with ESMTP id 6D88237B663 for ; Wed, 3 May 2000 13:08:50 -0700 (PDT) (envelope-from brdavis@orion.ac.hmc.edu) Received: (from brdavis@localhost) by orion.ac.hmc.edu (8.8.8/8.8.8) id NAA11043; Wed, 3 May 2000 13:07:59 -0700 (PDT) Date: Wed, 3 May 2000 13:07:59 -0700 From: Brooks Davis To: Nate Williams Cc: Alexander Langer , Matthew Dillon , hackers@FreeBSD.ORG Subject: Re: GPS heads up Message-ID: <20000503130759.A15403@orion.ac.hmc.edu> References: <200005031744.KAA63550@apollo.backplane.com> <20000503200006.A35116@cichlids.cichlids.com> <200005031957.NAA01354@nomad.yogotech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0pre4i In-Reply-To: <200005031957.NAA01354@nomad.yogotech.com>; from nate@yogotech.com on Wed, May 03, 2000 at 01:57:08PM -0600 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Wed, May 03, 2000 at 01:57:08PM -0600, Nate Williams wrote: > My former employer (SRI) has done lots of research, and have gotten a > receiver good to 1cm, but it takes about 24 hours for it to > 'synchronize' to that accuracy. With dual receivers, you can get 2-3 mm > accuracy by comparing the wavelength offsets, but it's really, really, > really expensive to build the hardware, and there's very little > practical use for that kind of accuracy. Actually, there's a physics professor any my old college does use that feature. He mounts them on buildings around SoCal with dataloggers to determine building movement due to earthquakes and general plate movement. -- Brooks -- Any statement of the form "X is the one, true Y" is FALSE. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message