idea for Neo 2nd generation: Accelerometer
myopenmoko at richip.dhs.org
Fri Jan 26 19:02:07 CET 2007
On Fri, 2007-01-26 at 09:41 -0800, Tim Newsom wrote:
> Ok Steve. I grant you that the first derivative of acceleration is
> velocity... How do you propose to gain any velocity information when the
> acceleration measured is zero as would be the case if you are at a
> constant velocity? This is why I am saying you would need some better
> source for velocity.
> I grant you that the times when a car is at a constant velocity may be
> few... Or it may be that when on cruise control on any flat road you may
> actually see zero or almost zero acceleration.
I probably shouldn't engage this thread since most of it is academic
till official word is made regarding accelerometers, but what the heck?
Theoretically, if one tells the device to assume the velocity at a given
point in time is zero, then by carefully tracking the acceleration at
various points in time, you can determine the velocity vector at
present. The accuracy will be limited by how accurate the accelerometer
is, the orientation of the device as well as the sampling rate, but with
the lack of a connection between the car's information bus (CAN), it's
AGPS can also help determine velocity prior to entering the tunnel
(which could be a good starting point for determining velocity based on
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