From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from nt.navisys.com.tw (navisys.com.tw [60.250.203.123]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id D87BB201B20 for ; Thu, 10 May 2012 21:20:54 -0700 (PDT) Received: from CJYPC (60-250-203-126.HINET-IP.hinet.net [60.250.203.126]) (authenticated bits=0) by nt.navisys.com.tw (8.13.4/8.13.1) with ESMTP id q4B4KjQe027799; Fri, 11 May 2012 12:20:46 +0800 From: "Jau-Yang Chen" To: "'Gary E. Miller'" Date: Fri, 11 May 2012 12:20:49 +0800 Message-ID: <012d01cd2f2d$7348b130$59da1390$@navisys.com.tw> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 14.0 Thread-Index: Ac0vLW6QkFIgDGAVT9idCYWv/xxB1Q== Content-Language: zh-tw Cc: thumbgps-devel@lists.bufferbloat.net, 'veronica' , tcf@navisys.com.tw, gloria@navisys.com.tw, 'lily' Subject: Re: [Thumbgps-devel] cold start of Macx-1 GPS receiver 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: Fri, 11 May 2012 04:20:55 -0000 Dear Gary, Frankly, we are curious why one GR-601W sample took so long time to fix the position when you tested it in the very first time. Did you ever issue cold start to test it? Is it back to normal (say, to fix position within one minute under open sky) afterwards? Yes, per tz's comment, if GR-601W keeps the ephemeris data collected in Taiwan, it won't help to hot/warm start in USA. On the contrary, some old GPS engines might mislead the internal algorithm and get deadlock. Of course, u-blox6 engine will apply the cold start algorithm automatically to re-collect the correct ephemeris data. > Also the Ephemeris doesn't help if you move more than about 500 miles from the last place it was turned on. Until it can get at least a 2d fix and new latitude/longitude, it won't know which satellites to look for. Best regards, JY -----Original Message----- From: Gary E. Miller [mailto:gem@rellim.com] Sent: Friday, May 11, 2012 12:44 AM To: Jau-Yang Chen Cc: 'Dave Taht'; thumbgps-devel@lists.bufferbloat.net; 'veronica'; tcf@navisys.com.tw; gloria@navisys.com.tw; 'lily'; Eric S. Raymond Subject: Re: [Thumbgps-devel] supercap vs. battery in Macx-1 GPS receiver Yo Jau-Yang! On Thu, 10 May 2012 18:38:41 +0800 "Jau-Yang Chen" wrote: > After being fully charge, the supercap in Macx-1 could last around 4 > hours, and around one week for Li-ion battery, Well, that explains my one hour cold start when receiving the sample units. One week hold-up is pretty short, and 4 hours hardly worth the effort. Luckily the thumbgps project is for always on, but for weekend use neither is good. Most mouse GPS have batteries are good for a month or more of standby. RGDS GARY --------------------------------------------------------------------------- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97701 gem@rellim.com Tel:+1(541)382-8588