From owner-freebsd-chat Wed May 3 15: 4:18 2000 Delivered-To: freebsd-chat@freebsd.org Received: from wopr.caltech.edu (wopr.caltech.edu [131.215.102.114]) by hub.freebsd.org (Postfix) with ESMTP id 272F337BE5F for ; Wed, 3 May 2000 15:03:54 -0700 (PDT) (envelope-from mph@wopr.caltech.edu) Received: (from mph@localhost) by wopr.caltech.edu (8.9.3/8.9.3) id OAA33647; Wed, 3 May 2000 14:59:30 -0700 (PDT) (envelope-from mph) Date: Wed, 3 May 2000 14:59:30 -0700 From: Matthew Hunt To: Poul-Henning Kamp Cc: chat@FreeBSD.ORG Subject: Re: GPS heads up Message-ID: <20000503145930.B33563@wopr.caltech.edu> References: <20000503200006.A35116@cichlids.cichlids.com> <2386.957377415@critter.freebsd.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <2386.957377415@critter.freebsd.dk>; from phk@critter.freebsd.dk on Wed, May 03, 2000 at 08:10:15PM +0200 Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org [ moved to -chat ] On Wed, May 03, 2000 at 08:10:15PM +0200, Poul-Henning Kamp wrote: > Not quite, the military system is only better because it has two > frequencies, and that doesn't improve things *that* much. So, I will apply my meager knowledge of pulsar observations to guess that the phase difference between the two frequencies gives you the integral of the electron number density along the path, and hence allows you to measure the delay introduced by the ionosphere, and subtract it off? (I have read elsewhere that the ionospheric fluctuations are the largest source of error, aside from SA.) -- Matthew Hunt * Stay close to the Vorlon. http://www.pobox.com/~mph/ * To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message