I see that there are 4 filter modes available -- Kalman, Q-GRAD, Q-COMP, and IMU. What is the difference between these, and which one should I be using?
The Kalman filter (which is currently the default filter) allows for rates of up to 250Hz, for both logging and real-time data acquisition. This is currently the filter that we recommend for everyday orientation data collection.
The Q-GRAD filter updates faster (up to 850Hz) and is more resistant to changes in magnetic field than the Kalman filter, but since it is slower at incorporating changes in the accelerometer and magnetometer readings it may take time to settle into the right orientation.
The Q-COMP filter updates at a rate of 850Hz or more over a USB connection with similar performance and accuracy to the Kalman filter. This is currently the filter we recommend for high-speed orientation data collection.
IMU mode does not do any orientation filtering (thus it allows for the highest data transfer rate of up to 1300Hz), and should only be used for getting data straight from the accelerometer, magnetometer, and/or gyroscope.