Warranty after fix for GTA02 GPS rework forSD card interferenceissue

[steve]

A proper Kalman Filter, I would think, would have such limits since it
should have a model of vehicle dynamics. 
Andy do you have any idea of the duration of SD IO? 


-----Original Message-----
From: community-bounces at lists.openmoko.org
[mailto:community-bounces at lists.openmoko.org] On Behalf Of Andy Green
Sent: Thursday, July 31, 2008 7:44 AM
To: List for Openmoko community discussion
Subject: Re: Warranty after fix for GTA02 GPS rework forSD card
interferenceissue

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Somebody in the thread at some point said:
| steve schrieb:
|>   Amaybe when SD I/O occurs one could use the accelerometers to dead
reckon?
|
| Dead reckoning without gyros is pretty hard.  In theory, the two 
| accelerometers are not mounted in the same place and thus could be 
| used to derive rotation, but in practice they're pretty close to each 
| other, and given the noise of measurement one is unlikely to derive a 
| good rotation from them.

I don't think we need to worry about it, but in fact we wouldn't need to
dead-reckon.  All we would need it for would be to put a ceiling on claims
from noisy GPS about what accelerations we could have experienced.  If the
GPS sample says we jumped 100m in 1s, but the accels didn't really see
anything, we could ignore or meddle with the GPS sample.

Whether that is any better than just filtering between previous and later
samples I doubt.

- -Andy
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