GTA04A5 ready to be pre-ordered

Jiří Pinkava j-pi at seznam.cz
Thu Jan 24 08:31:12 CET 2013


Dne 24.1.2013 07:35, robin napsal(a):
> maybe I have misunderstood then. From your initial response I understood that
> the gps receiver of the gta04a4 would have a lower sampling frequency than the
> gps receiver of the gta04a5 due to some hardware wiring and as I you stated
> in the gta04a5 anouncement the gta04a5 can provide now with the hardware fix a
>
> * the GPS receiver can provide a 1 second impulse interrupt to the CPU
It is interrupt to synchronize time precisely, this is not related to 
sample rate but to time synchronization.

This artice explains it nicely

http://linlog.blogspot.cz/2009/07/synchronizing-ntp-server-to-gpspps.html
>
> so my conclusion was that the gta04a4 cannot sample at with 1Hz but must be
> slower. I haven't had the time to change my gta02 to an gta04 so I could not
> test the difference myself, but I remember reading the thread [1] it was re-
> ported that the gta02 gps was capable to sample at much higher rates (4Hz
> standard, max 20Hz reported).
> Sampling at 1Hz at 60km/h means an update every ~17m which in most navigation
> situations should be ok, but if you have complex crossings with more than two
> alternative lanes then the lag becomes a problem.
>
> best regards
>
> robin
>
>
>
> [1] http://comments.gmane.org/gmane.comp.handhelds.openmoko.community/62642
>
>
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