Publications

Open-source resources available on this website are provided under the GNU General Public Licence unless an alternative licence is provided in source.

Open Source IMU and AHRS algorithms

In 2009 Sebastian Madgwick developed an IMU and AHRS sensor fusion algorithm as part of his Ph.D research at the University of Bristol. The algorithm was posted on Google Code with IMU, AHRS and camera stabilisation application demo videos on YouTube. The algorithm received thousands of downloads but the code project was never maintained or updated. All resources are now provided and maintained here. The algorithm source code is available in C, C# and MATLAB. The source code also includes Madgwick's implementation of Robert Mayhony's 'DCM filter' in quaternion form.

Resources

• Original internal report (.pdf)
• IEEE conference paper (IEEE Explore)
• MATLAB code (Includes example data and script)
• C# code (x-IMU Example project used to create this video)
• C code (Header and source files)

User contributions

• LabVIEW library by Roger Isaksson (Google Code)

Quaternions

3D orientations are commonly represented using rotation matrices and Euler angles. Quaternions offer an alternative representation that is computational more efficient than rotational matrices and is not subject to the problem of a singularity (AKA gimbal lock) that can make an Euler angle representation hazardous. The resources below include a document summarising this use of quaternions and an accompanying MATLAB library.

• Quaternions (.pdf)
• MATLAB quaternion library (MATLAB functions and test script)