GTSAM includes a state-of-the-art IMU handling scheme based on:

• Todd Lupton and Salah Sukkarieh, “Visual-Inertial-Aided Navigation for High-Dynamic Motion in Built Environments Without Initial Conditions”, TRO, 28(1):61-76, 2012.

Our implementation improves on that work using integration on the manifold, as detailed in:

• Luca Carlone, Zsolt Kira, Chris Beall, Vadim Indelman, and Frank Dellaert, “Eliminating conditionally independent sets in factor graphs: a unifying perspective based on smart factors”, ICRA 2014.
• Christian Forster, Luca Carlone, Frank Dellaert, and Davide Scaramuzza, “IMU Preintegration on Manifold for Efficient Visual-Inertial Maximum-a-Posteriori Estimation”, RSS 2015.

If you use this factor in academic work, please cite the publications above.

In GTSAM 4, a newer and more efficient implementation based on integrating on the NavState tangent space is enabled by default. To switch back to the RSS 2015 version, set GTSAM_TANGENT_PREINTEGRATION to OFF.