From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.perfora.net (mout.perfora.net [74.208.4.195]) by huchra.bufferbloat.net (Postfix) with ESMTP id A2877208AD0 for ; Wed, 2 May 2012 06:40:45 -0700 (PDT) Received: from [192.168.83.3] (c-76-97-152-51.hsd1.ga.comcast.net [76.97.152.51]) by mrelay.perfora.net (node=mrus2) with ESMTP (Nemesis) id 0LxxbI-1S4pxO193U-015nhV; Wed, 02 May 2012 09:40:43 -0400 Message-ID: <4FA13959.9050405@techstarship.com> Date: Wed, 02 May 2012 09:40:41 -0400 From: "Ron Frazier (NTP)" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.9) Gecko/20100722 Eudora/3.0.4 MIME-Version: 1.0 To: thumbgps-devel@lists.bufferbloat.net References: <20120501151435.4a6a5373.gem@rellim.com> <20120502033345.GA11913@thyrsus.com> In-Reply-To: <20120502033345.GA11913@thyrsus.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Provags-ID: V02:K0:gNApsrs2Doe43zuHNs82zC3HAJXe3zBrg4pNR6As+yw DcO2U6odM+Joh1lb4uB/kxLL/FCziRW45Shj9WBbqC4ZJijJ3l PQFeIs10SjTznjHiQ2TLT6FdrTrh+UMtjKp9gFfAmAcpG4Gvxe ulSV9uZ4/FoADLaHlCVD2XQ0Ytw2WYZSrYpwLjTw+/dOPDYRJG 1mm2DWVEgt4O7NZH1pBB22nQftGJrbgE3fqHHo5xEgxULYBSRx XSxGrI1SQdKDDRrfzMABD1iIvjxI6VafK7tfHGAV6f0ApGY0Qx gmWNS08xRSfS2xlpfnfLGoYd1qjL+IllL05dQeT/l0M28F1FPH 0WQZg1Mojf5rDMCHeyvEojf908qCJS/80v3Ml9Px/ Subject: Re: [Thumbgps-devel] [gpsd-dev] PPS over USB X-BeenThere: thumbgps-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 May 2012 13:40:45 -0000 On 5/1/2012 11:33 PM, Eric S. Raymond wrote: > Dave Taht: > >> I'm a little confused. >> >> There are two threads going by today. One is about a sirfIII and the >> other a ublox 6 >> >> I have been assuming they are one and the same, but perhaps I'm confused. >> > You are. The first set of prototypes, from UniTraq, were SiRF-III + CP2101. > These won't do - turns out the CP2101 driver can't wait on a handshake state > change because the vendor never released enough programnming information. > > Gary is talking about the second set of prototypes, from NaviSys. > That's the uBlox + PL2303 device. It works. The next step is to > get them into volume production. > > >> Secondly an item that has not been looked into much is the quality of >> the antennas, or the quality of the clock source when only a single >> sat is available.... >> > Quality of antenna will matter for the device's ability to function in > weak-signal conditions, e.g. indoors. Clock time should be OK even with > a single sat - multiple birds are needed for the spherical trig to compute > position, but atomic time you get directly from each sat sample. > > >> Thirdly, wow.... when can I get one of these puppies to play with? >> > Gary has three. He's keeping one and sending me the second. Since OpenBSD > has no TICMIWAIT, Chris Kuethe is out of contention for the third and it > should logically go to you. > Hi guys, Just wondering. On the USB + PPS + PL2303 concept, has the long term variation that has been observed in NMEA data in other similar units without PPS been accounted for? I have personally observed a variation in NMEA data on my Globalsat Sirf III USB device of up to +/- 70 ms over several days. Will having the PPS coming though USB solve that problem? Sincerely, Ron -- (To whom it may concern. My email address has changed. Replying to former messages prior to 03/31/12 with my personal address will go to the wrong address. Please send all personal correspondence to the new address.) (PS - If you email me and don't get a quick response, don't be concerned. I get about 300 emails per day from alternate energy mailing lists and such. I don't always see new messages very quickly. If you need a reply and have not heard from me in 1 - 2 weeks, send your message again.) Ron Frazier timekeepingdude AT techstarship.com