From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.perfora.net (mout.perfora.net [74.208.4.194]) by huchra.bufferbloat.net (Postfix) with ESMTP id 0CAC1201A91 for ; Wed, 2 May 2012 21:07:23 -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=mrus1) with ESMTP (Nemesis) id 0M2387-1SAL4W49Nr-00u5fg; Thu, 03 May 2012 00:07:22 -0400 Message-ID: <4FA20476.5070204@techstarship.com> Date: Thu, 03 May 2012 00:07:18 -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: "Gary E. Miller" References: <20120501151435.4a6a5373.gem@rellim.com> <20120502033345.GA11913@thyrsus.com> <4FA13959.9050405@techstarship.com> <20120502124227.28ef9fa6.gem@rellim.com> In-Reply-To: <20120502124227.28ef9fa6.gem@rellim.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Provags-ID: V02:K0:dZ2IG00Cvbpv56zkh2ajldvwepcHtM/90gTz7rKmj5M Yqp1qJ7x8Zr9JsPzUVx3dEPIBGlJLEO1ZLukHFbcmDhDFyKNaB MRbzZH1ZzVIIPyM1++Stzf4tOpICmmCNLD7jNalaomwyLYoL6v cEsi6HcHOPqZIo90eOL+7J2VnIDIfrEt2GMg7M8HfjTBounkj4 45wynyzQk6yZcPEUJU6IOr7mz4e/5WGpr0a26uZZwPsrt8xHUy 93dNfqCwAT3RtyLf+p8SMLwcX5o6bh7ljdWx5K7qQ/5YPtJmRA wfBEw1mt5F722h4iRKQOk2nASfEYAkkrv4qL2PwBaxugSyHW5d YgktI4jYCfq+3L+5Yi+aQFFqoBkKXOv+tD5HlHX4x Cc: thumbgps-devel@lists.bufferbloat.net 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: Thu, 03 May 2012 04:07:24 -0000 Hi all, Gary said his posts are bouncing, and to please post this to the list. So, this post serves that purpose, as well as being my reply. Thanks for the note Gary. I guess you're right, as long as PPS is in control. I presume you could still get the numeric value for the second from NMEA and start time for it from the PPS. Check what return address shows up when you send a message to thumbgps-devel and make sure it matches what you signed up with. You may have to put a custom identity in your email, like I did with my return address above, to get it to accept your posts. Sincerely, Ron On 5/2/2012 3:42 PM, Gary E. Miller wrote: > Yo Ron! > > On Wed, 02 May 2012 09:40:41 -0400 > "Ron Frazier (NTP)" wrote: > > >> 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? >> > Of course, it is an unavoidable side effect of the variable length NMEA > protocol and the variable time for the GPS to compute depending on > satellite configuration. > > >> I have personally observed a >> variation in NMEA data on my Globalsat Sirf III USB device of up to >> +/- 70 ms over several days. >> > Yup, sounds right. If you look closely, the time jump is when the > number of sats used in the cmopuatation changes. > > >> Will having the PPS coming though USB >> solve that problem? >> > Nope. NMEA is NMEA and PPS is PPS and they are not related except > to the partial second. So the NMEA jitter will still be there, but who > cares when the PPS is stable to 0.5 milliSec. > > BTW, for some reason thumbgps-devel rejects my posts, so pass this on > to the list. > > RGDS > GARY > --------------------------------------------------------------------------- > Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97701 > gem@rellim.com Tel:+1(541)382-8588 > -- (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