Gyroscope drift on mobile phones

Question

Lots of posts talk about the gyro drift problem. Some guys say that the gyro reading has drift, however others say the integration has drift.

1. The raw gyro reading

Answer 1

In this discussion both Ali and Stefano have raised two fundamental aspects of drifts due to ideal integration.

Basically zero mean white noise is an idealized concept and even for such ideal noise integration offer higher gain over lower frequency component of noise, which introduces a low frequency drift in the integrated signal. By theory the zero mean noise should not cause any drift iff observed over significantly long time but practically ideal integration never works.

On the other hand, even a minor dc-offset in the reading (input signal) can cause a significant drift over a time, if an ideal integration (loss-less summation) is performed on it. It can ramp up a very small dc-offsets in the system, as ideal integration has infinite gain on DC component of an input signal. Therefore for the practical purpose we substitute ideal integration by a low pass filter whose cut-off can be as low as required but can not be zero or too low for practical purpose.