jremington:
Then they use some other external reference for yaw. A gyro alone cannot determine the yaw angle.
no, the ones I mean don't use external references, and of course they can retrieve relative yaw anglex by their gyros, e.g. for LEGO:
https://shop.lego.com/de-DE/EV3-Gyrosensor-45505
all can retrieve the yaw angle (e.g., for navigating a robot car) though.
so if they can , why can't a MPU6050?