[ayeckley]

I see two relatively simple things that might be done, that are sort of device-agnostic. Rather than focusing on eliminating gyro error, perhaps you could instead make it easier to tolerate.

The first solution (the higher-tech route) would be to use the accelerometers in conjunction with the gyro. Since the majority of the gyro error is accumulated during gross impacts (as opposed to "normal" robot vibration), preserve the "good" value of the gyro until each impact is over. Then, compensate for the FPGA-produced value via addition or subtraction. A more sophisticated version of this approach might calculate the impact vector, and adjust the heading output based on the gyro's directional impact sensitivity (which I suspect you'd have to measure yourself). Dunno, never tried that before; probably not worth the effort frankly.

The second (lower tech) solution is to give your turret operator the ability to re-zero the heading when necessary. For example, whenever the turret passes through an "observed" orientation (0 deg, 90 deg, etc.), give them a button to press which forces the gyro-based heading value to "agree" to that orientation. The upside is that this is easy to program, the downside is that it takes a little more work for the turret operator; ideally it would still result in an easy-to-operate system. We did something functionally equivalent on our Breakaway bot, wherein if things got hinky for the driver he could look at the indicated heading on the dashboard (to verify that it had indeed drifted) and manually re-zero the gyro heading by momentarily reorienting the robot and hitting a "re-zero" button. It sounds a lot more complicated than it was. In the end our competition driver decided that he preferred to operate things robo-centric rather than field-centric but at least he had the option available. Other drivers preferred the field-centric approach.

I'm sure there are other, probably even better ways to do this. I don't think there's a "perfect" gyro out there that will eliminate the problem - best to find a way to work around it instead.