Because 6 axis MotionFusion has no way to directly sense the earth’s magnetic field, it estimates heading by integrating the gyroscope sensor outputs. The gyroscope sensor will have some small amount of noise and may have small biases. Since the technique of gyroscope integration keeps a running sum of gyroscope sensor outputs and those sensor outputs include small errors, the sum will slowly accumulate an error over time. 6-axis MotionFusion can only correct part of this error using information from the accelerometer.

Because 6 axis MotionFusion has no way to directly sense the earth’s magnetic field, it estimates heading by integrating the gyroscope sensor outputs. The gyroscope sensor will have some small amount of noise and may have small biases. Since the technique of gyroscope integration keeps a running sum of gyroscope sensor outputs and those sensor outputs include small errors, the sum will slowly accumulate an error over time. 6-axis MotionFusion can only correct part of this error using information from the accelerometer.

9 axis MotionTracking® combines gyroscope, accelerometer, and TMR magnetometer sensor data. The resulting angular frame is relative to both gravity (down) and north.

The advantages of 9 axis MotionTracking® over 6 axis MotionTracking® are that 9 axis MotionTracking® results are usable for navigation and other applications which require information about the angle relative to north. It also eliminates any heading drift which may be present in a 6 axis MotionTracking® solution so that users are pointed in the correct direction without delay due to recalibration.