Various mobile robots are used for practical mission such as package delivery, house cleaning, mowing the lawn. The
attitude of mobile robots describing as Euler angles is essential data to complete the mission. The attitude estimation is
generally fused by the algorithm to compensate the measurement errors of inertial measurement units and
magnetometer. The magnetometer is especially good to measure the yaw angle without drift. However, yaw angle
measured by magnetometer is easily disturbed by magnetic objects such as steel, iron bars, electromagnetic sources. So,
it is need to additional process rejecting the magnetic disturbance. In this talk, we proposed an algorithm to reject the
magnetic disturbance to be stable attitude estimation for practical mobile robots.