I know this question is asked before, but the reason why was still not clear to me.
If you've a 6-DOF IMU, the gyroscope measures is degrees/s or radian/s.
Why do we want to convert the body rates to Euler rates. If you could measure the gyroscope angle by multiply it by dt. Than the starting point is the reference for the object. So this calculates the angle with respect to the body frame with a reference to the starting point. Why bother using the Euler rates?
I know Euler angles describe the orientation of an object with respect to a fixed coordinate system, the problems that Eulers angles has like gimbal lock and how to solve those with quaternions. But what are the advantages/ difference of using Euler angles and why instead of multiply the output of the gyroscope by elapsed time (dt).
Theoretically the drone would be able to fly in both cases.