[nathan_hui]

Multiple inputs from multiple sensors couple together should give the best possible approximation of measured phenomena, right? Therefore, following that logic, a gyro and encoder inputs (from the wheels, if that wasn't clear) should give you a fairly good approximation of which direction you are pointed on the field. A gyro won't care about being slammed, but won't (I don't think) have the stability and resolution that you could get from examining the encoder input from the wheels, which would be useless when hit and somewhat useless when skidding.

But oh, this wouldn't work for WCDs or tank treads, only robots with omniwheels, or perhaps swerve drives (and I have absolutely no idea about mecanum). I see your point.

I guess I've just proved that it really depends on what you're measuring and the nature of measured phenomena.