GPS

Russell Sears sears at cs.berkeley.edu
Fri Jul 11 23:34:52 CEST 2008


I'm in the san francisco bay area, and am seeing very slow GPS fixes. 
It took 5 minutes to get the time code from the satellite this morning 
(didn't get a fix in 12 minutes...), and I've only gotten a fix once so 
far (after > 10 minutes...), and it's failed to get a fix during a few 
~10 minutes walks outdoors.  I've been carrying the phone screen up, 
away from my body, away from buildings taller than a story or two...

Anyway, if you still haven't duplicated the problem, let me know.

Also, I'm getting a bit of GSM data noise on my speaker during phone 
calls.  Is that normal, or is it unexpected signal leakage?  I plan to 
retest GPS with the GSM (and all other radios) disabled.

-Rusty

steve wrote:
> Well,
> 
>    Sean is sick in bed from taking Malaria shots since he is traveling to
> Ghana to speak. I have been
>    Busy at the wharehouse and Wolfgang is aware of your issue and we have
> folks on it trying to duplicate
>    the issue and figure it out. Sean, for example, has had no issues in TPE,
> west coast USA, east coast USA,
>    and columbia with his phone.  So, after we duplicate the problem then we
> can figure the cause. Software,
>    component failure, test leakage.
> 
>    On the inside of your phone there is a datecode, serial number etc.
> Email that to wolfgang
> 
> Steve  
> 
> -----Original Message-----
> From: Marcus Bauer [mailto:marcus.bauer at gmail.com] 
> Sent: Monday, July 07, 2008 10:05 AM
> To: List for Openmoko community discussion
> Cc: Sean Moss-Pultz; Wolfgang Spraul; steve
> Subject: Re: GPS
> 
> On Mon, 2008-07-07 at 18:24 +0200, Mathias Ballner wrote:
>> hi all,
>> today i tried to get the gps running, but i didn't get a gps fix i 
>> tested it with tangogps (nice tool!) and openmoko-agpsui the only 
>> output i got was:
> 
>> http://scap.linuxtogo.org/files/6d11990f0c82d92f0252742d7ef44950.png
>> what do i do wrong?
>> mathias
> 
> It seems nobody gets a quick fix. Times range from 10 to 60 minutes if any
> fix at all. There is a similar thread running on the developer list but no
> answers from Openmoko. Normal for a cold start would be 45secs-2min and with
> agps ~15secs. This is industry standard and stated on the specs page of
> u-blox. The GTA01 (Neo 1973) gets a fix in one minute after a cold start.
> 
> All modern chips (and the u-blox is a modern chip) can get a fix without
> downloading the full almanac (which takes 12.5 minutes). The ephemeris is
> sufficient and comes in 30secs.
> 
> I think this is an important issue and hope that Sean or Wolfgang can give
> answers. I CC'd Steve too, because this equally effects the VAR markets.
> 
> If they don't answer it is probably the best to send your FR back before the
> warrenty expires and buy a new FR once this issue is resolved.
> 
> Marcus
> 
> 
> 
> 
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