Reason for GPS problems found!

Timo Jyrinki timo.jyrinki at gmail.com
Fri Jul 18 11:25:34 CEST 2008


2008/7/17 Timo Jyrinki <timo.jyrinki at gmail.com>:
>> | I tried the kernel too, but it didn't help. Didn't get any fixes in 3
>> | minutes when having SD card in (not in use, ie. maps not there).
>> | Removed the SD card and got a TTFF in 34 seconds.
> I haven't seen any other readily available builds besides those
> mwester's andy+wester builds, but hopefully others can test eg. them
> also.

I now okpg upgraded to the current stable ones including the SD fixes,
and did a bit more testing than before. I now got a fix in this
"difficult" place, albeit after 140-250 seconds instead of 34
depending on the run. What I didn't mention earlier is that I used the
assistive data to get that 34 seconds (ie. power on in AGPS UI, then
quickly switch to terminal and retrieve the assistive data from
u-blox). Somehow it doesn't seem to help as much (or at all) now with
SD card in, since I get TTFF of over 100s both with or without, or so
it seems. A few times I didn't get a fix in 5 minutes, so it's
definitely on the borderline now instead of being reliable like
without SD card.

But anyway, the great news is that this is definitely a big
improvement. This is in a place where I used to be for half an hour
without getting even UTC time from GPS if I used SD card, and now I'm
getting fixes with SD card in.

It seems it's not as good as without SD card, but definitely a visible
improvement.

-Timo




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