smirfi at googlemail.com
Mon Jul 14 11:08:01 CEST 2008
again: its not a software issue. This chip should work out of the box.
39 s to fix with good antenna is possible on my dev board, without any
agps or anything.
2008/7/14 Timo Jyrinki <timo.jyrinki at gmail.com>:
> 2008/7/13 BlueStar88 <BlueStar88 at xenobite.eu>:
>> Feeding assist data to compensate bad hardware based reception is no real
>> solution, since there are some FRs, which seem not to have any problems to
>> get a fast fix at all.
> My personal current belief is that those FRs are generally no better
> than eg. yours or mine. It's simply a matter of software used and
> especially the place used (some countries have also better GPS
> coverage than others), plus whether one really has a table or so where
> the device can easily be mounted firmly. If you hold it in your hand,
> still otherwise, it might not be steady enough to get the fix (or does
> someone know otherwise, eg. what kind of movement might corrupt the
> received bits?). Or are there some people who get a fix while moving
> Neo around?
A good GPS reciever like some properly build SIRF3 systems and others
get a fix within 1 minute under "good conditions" (clear view to sky)
cold boot no matter how you hold your device. (proved here several
times) The openmoko does not get a fix in reliable time (<3 minutes).
If you plug in a external antenna and keep it away from the device it
works like with a good SIFR3 chip. So lets face it: IT IS NOT A
> Since the software has zero GPS data saving features etc., it's no
> wonder people easily think "it's broken". Especially, like in my case,
> if people don't have previous GPS usage experience or don't know how
> hard it's actually to "start from scratch" (scanning the whole sky)
> without any eg. estimate on current whereabouts or any other help. And
> also it doesn't help that if eg. people use AGPS UI which clears any
> received data every time it's started. One reason I believe it's not
> bad hardware reception is that when the fix is gotten, the fix stays
> better than on many "real" GPS hardware.
As you can see if you search for the thread "GPS External antenna
detect issue" it is a hardware issue.
And there are a lot of people on this list having experienced with gps
systems like me.
Reading the manual of the chip you can see, that it should work out of
the box without "software" support.
39 s is what this chip is able to. But of course not if the antenna
system is broken.
Some people expect it to be a combination of:
* broken antenna switch
* bad antenna
* antenna too near to device
> Still, I've yet to experiment more on what would be best ways to get
> the initial fix. Even if feeded initial data, it seems relatively
> impossible to get the fix around my place. I'm not sure what could be
> improved still for the first fix, since after the fix is gotten it
> stays so well one would imagine the fix should also be possible to get
> in an (relatively) open area with a clear sky.
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