Re: [Thumbgps-devel] cold start of Macx-1 GPS receiver

["Jau-Yang Chen" <cjy@navisys.com.tw>]

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" <cjy@navisys.com.tw> 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
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