So I can get away with two accelerometers measuring X/Y acceleration in
the horizontal plane, and a single axis gyro measuring yaw to track
position over a time period, given an accurate temperature reference and
correcting for gyroscopic precession?  Would this redundancy avoid
double integration problems?  What kind of accuracy can I expect?  Where
can I find the integration formulas I need?

I should have been a physics major...

- Jeff Cesnik


Sean Breheny wrote:

> The problem with using accelerometers to measure position information
> is
> that it requires integrating twice (accel = 2nd deriv of position) and
> this
> means that any little offset error in the output of the accelerometer
> gets
> accumulated over time. So, the setup would be accurate for a little
> while
> but after a few minutes (a guess abt exact length of time), the whole
> setup
> would need recalabration to be accurate.
>

<snip!>

> Now, you can integrate ang. accel. with respect to time and get an
> approximate answer.
>
> IMHO, a gyro would be much more accurate and maybe even not as
> expensive
> (if you end up needing two accelerometers). There is one consideration
> with
> the gyro, though. Due to friction in the gyro bearings and other
> factors,
> the gyro will begin to precess and re-align its axis after a while.
> So, it
> is difficult in general to sense angle by inertial means.
>
> I think that you probably just want to use a plumb weight and an
> optical
> encoder wheel! :-)
>
> Good Luck
>
> Sean
>
> +--------------------------------+
> | Sean Breheny                   |
> | Amateur Radio Callsign: KA3YXM |
> | Electrical Engineering Student |
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