If there is a standard interpretation of bias repeatability as it applies to a gyroscope, what is that interpretation?
This document indicates that it represents the average change in bias between successive turns-on. So if I estimate bias to be 10 deg/hr and the bias repeatability is 1 deg/hr, I could power off the gyroscope, power it on, and expect the next bias estimation to return something between 9 deg/hr and 11 deg/hr (in 68% of trials).
This forum implies that it reflects how bias changes as the gyroscope ages, but it isn't obvious to me why. If initial bias is changing over years of use, but I'm correcting that bias with proper bias estimation each time, this aspect of aging should not affect performance.
Bias repeatability provides an estimate for long-term drift in the bias, as observed during 500 hours of high temperature operating life at +105C.
This seems to estimate the change in bias over a single 500-hour run. So if I leave my gyro on for 500 hours after bias correction, I would observe the bias after that time period to be 252 deg/hr (value taken from spec) on average. If I don't set aside moments in that 500 hours for bias re-estimation, this results in severe gyro inaccuracy.
This other IMU shows its "Bias repeatability (1 yr)" as 1800 deg/hr, which could be (1) the average bias change in a continuous 1-year test, (2) the average change in turn-on bias over a year of usage, or (3) something else entirely.
These different interpretations have drastic differences in implied performance. So while I'm analyzing spec sheets to find the right part for my use case, is there a uniform definition of bias repeatability, or does each manufacturer design their own test to reveal different information about their device?