Wang Li, Zhang Zheng, and Sun Ping


AHRS, gradient descent, inertial sensors, magnetic sensors, orientation estimation, quaternions


In this paper, an improved quaternion-based attitude estimation algorithm is developed for attitude and heading reference system (AHRS). It can be used as an attitude estimation method in a quadrotor. In the proposed algorithm, we utilize quaternions to represent the rotation between navigation frame and body frame. The level attitude (pitch and roll) is determined by the tri-axis accelerometer and the tri-axis gyroscope using the gradient descent algorithm. To avoid magnetic distortion in the level attitude estimation, we only use magnetometer output to estimate the yaw angle. Besides, an ellipse hypothesis compensatory model is adopted to compensate the magnetometer output. A small-size AHRS experimental platform is built in the paper, which can be used as a quadrotor flight controller. Experimental results show that the improved approach can track the quadrotor flight controller movement in real time with free-magnetic distortion impact and reduced delay in fast-moving conditions.

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