Picking a gyro for field-centric swerve control

[vamfun]

Originally Posted by Golto

What about using a compass. Wouldn't this give absolute position, without the need for gyros? Sure, they're a little more expensive, but their accuracy would be much more than that of a gyroscope.

This little 1 deg compass is sure affordable. http://www.sparkfun.com/commerce/pro...oducts_id=7915. Not sure what the output 2.5 deg rms error spectral characteristics are like.

In the short term, the fine gyro could beat this for accuracy given a good initial alignment... but that's tough to do in FRC competitions.
Edit:

Alex:Others have reported (and it makes a lot of sense) that the compass modules they've used are very sensitive to the "natural" EMI environment around the permanent magnet motors in our bots. My own limited experience with such modules outside of a FRC environment matches their observations, so I don't have a high degree of confidence in that approach.

I too have not used a compass on an FRC and had this concern. I would guess the EMI noise would be amenable to low pass filtering and used for longer term automatic updating of the integrated rate. But again, we have introduced a two sensor complexity.