I've been working on a microchip-based system to stabilize a sensor platform
using an ADXL202 and an angular rate sensor.  The platform is moving around
in all directions (it's mounted on a robot) so the linear ADXL can't really
be trusted to give a consistent or even accurate reading.  It has been off
by as much as 80 degrees in the limited testing I've done.  Most of the
correction is currently coming from the integrating the rate sensor, but
it's subject to too much drift and really needs the corrections from a
linear accelerometer.  Does anybody know a work-around to this problem?

Right now it's integrating at about 60Hz, and checking tilt on the ADXL
every 100ms, then correcting 1/10th the offset indicated by the ADXL to
create a crude time delay filter.  This combination (so far) gives the best
stability at low levels of tilt, but at high rates of tilting (<150
deg/second) the position vector takes too long to catch up to where it
should be.

If you need or want more details let me know.

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