@michinyon
If true acceleration is not noise in the system, what is it then?
@longlongvn
As jjspierx pointed out you will need a magnetometer as well if you need a precise yaw measurement.
@wturn
To translate the gyro rate in to an angle simply multiply the reading by the delta time as I described in the blog post, but it will properly drift a lot if you use a gyro only.
@aziz-qessate_arduino
What do you mean? Please describe it in more detail.