GPS problems, summary

Christian Adams morlac at morlac.de
Wed Jul 16 23:06:42 CEST 2008


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thanks for your summary ..
and also a lot of thanks go to the OM-team for such fast response  
(and solution) and the patience with some annoying people on this  
lists ..

Morlac

Am 16.07.2008 um 21:38 schrieb Alasal:

> A summary of everything related to the GPS problem.
>
> Does the people of Openmoko know the problem?
>  - Yes.
>
> Do they work on the problem?
>  - Yes, they are actively searching for a solution.
>
> What is the problem?
>  - The Openmoko Freerunner have a long TTFF with the SD card in the  
> phone. So it takes a long time (10min+) before you get your first  
> GPS data.
>
> Wat is TTFF?
>  - This is the time to first fix of the GPS. This is the time the  
> GPS has needed to get the first clue on where you are on planet  
> earth. So you have to do this only once. After you have a FF (first  
> fix), you can get more fixes without any problems with the SD card  
> in the phone.
>
> So if we have a first fix, the SD card isn't blocking the GPS anymore?
>  - yes, the SD card isn't blocking the GPS if we have a first fix.  
> (Some people even claim it's more stable)
>
> Does they have a solution?
>  - yes. Their is already a highly alpha software workaround. The  
> software just disables the SD card when the GPS tries to get it's  
> first fix They are also examine a hardware solution.
>
> Do we have to return our Freerunners to Openmoko?
>  - Probably not, because the software workaround should work too.
>
> But we can't read of the SD card when the GPS is on?
>  - Wrong, you will be able to read the SD card when the GPS is on.  
> You will probably not be able to read the SD card when you're  
> starting the GPS (appr. 30 sec), because the GPS will only block  
> the SD card when it's searching it's first fix. After that you will  
> be able to read the SD card again.
>
> Is their a better software solution?
>  - Maybe. From reading the mailing list, I have understood that  
> half the Openmoko team is looking into this bug. All this  
> information is only 1 à 2 days old and the bug is also young, so I  
> suspect they can finetune the software workaround and make it only  
> slowdown the SD card or even better.
>
> Did Openmoko test the GPS with a SD card in it?
>  - yes
>
> Whey didn't they find it while testing the Freerunner?
>  - Because they have to do the tests with a fake GPS signal and  
> with that signal it worked. (In a fab you haven't a decent GPS  
> signal) They already have modified the test, so it correspond the  
> GPS signal better.
>
> Summary of the summary:
> You will be able to use the SD card in the same time of the GPS  
> except for the first appr 30 seconds. (And that's the worst case,  
> because maybe Openmoko can find better hacks/fixes)
>
> ps: I have read all the mails about the GPS problem, but I'm still  
> human. If there is a fault or wrong conclusion in this summary,  
> please let the community know.

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   eMail:	morlac at morlac.de
		adams at stud.informatik.uni-trier.de
   Jabber:morlac at skavaer.homelinux.org
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