gpsmikey:
A gyro is a short term (yeah, I know - define "short term" - depends on quality of the gyro ($$$)) way to look at movement. All gyros tend to wander over time and you need to have some way of calibrating or zeroing it out periodically or you are always going to get "deviation from normal".mikey
My gyro has to have the string wound up on the shaft an pulled occasionally.
Paul