A Novel 6-D Tracking Method by Fusion of 5-D Magnetic Tracking and 3-D Inertial Sensing

Pose tracking based on a permanent magnet is not limited by line of sight. In general, a high-remanence and axially magnetized cylindrical permanent magnet is utilized as the magnetic source, which is regarded as a magnetic dipole model. However, this magnetic tracking approach cannot estimate the rotation information along the direction of the magnetic moment. Thus, only 3-D linear motion and 2-D rotational motion of the magnet can be tracked. On the other hand, inertial sensors provide effective 3-D orientation tracking. In this paper, an inertial measurement unit was attached on the surface of a permanent magnet. Then, the tracking information of these two modes was fused based on the adaptive weighted fusion algorithm. Experiments show that the full 6-D pose is acquired with an improved orientation accuracy, where the average orientation errors for <tex-math notation="LaTeX">α </tex-math> , <tex-math notation="LaTeX">β </tex-math> , and <tex-math notation="LaTeX">γ </tex-math> , obtained by the fusion algorithm, were 0.81°, 0.93°, and 1.26°, respectively. This paper is helpful to those who want to accurately track the full 6-D pose of an object.