How to get angles to which a device was rotated using info from an IMU6 sensor (gyroscope and accelerometer)?

Question

I have a device with an IMU6 sensor. When it is laying on the table, the gyroscope and accelerometer data are constantly changing. The values between two measurements are similar, but they are never equal. There is always noise.

I need a formula for calculating the real angles to which the device was rotated if rotation has really happened. This will be used for game controlling, so I need as small an input lag as possible (I can't accumulate inputs to a buffer and then smooth them; that will give too big a delay).

How do I calculate the real rotation angles?

Answer 1

No matter what you do, every measurement is noisy.

If your noise is too large, for your application, you need to filter it, and combine multiple observations.

But any kind of filtering has to be causal in reality (no effect without prior cause), and hence leads to lag. No way in this world around that! However, averaging is a pretty bad filter, so maybe a different filter would fit you better. But it's impossible to advise you on a better filter with the info you've given: we don't know your noise PSD, how sensitive your game is in terms of which frequencies, and what your acceptable lag is for different frequencies.