An Electromagnetic Tracking Method Based on Phase Difference Detection

Electromagnetic tracking has widely been used in many fields, such as virtual reality, motion tracking, and biomedicine. Especially in surgical navigation systems, electromagnetic tracking offers a cost-effective alternative to traditional X-ray fluoroscopy. In this paper, we present a new magnetic tracking method based on phase difference detection. Two 3-axis magnetic sources and one 3-axis sensor are needed in the tracking system. The position and orientation of the sensor can be obtained simply by measuring the phase difference between the square of the synthetic magnetic induction intensity at the position of the sensor and the square of the excitation current of the magnetic source. The experimental results indicate that this method has a good tracking accuracy and speed. The mean position error is less than 0.1 cm, and the theoretical tracking time can be less than 3.5 ms when the frequency of the excitation current is no less than 1 kHz. Furthermore, antinoise simulations show that the tracking performance of this method is more robust against environmental noise than that of existing methods. Therefore, the electromagnetic tracking method proposed in this paper has good application prospects in many respects. It enables real-time tracking with high accuracy and a strong antinoise ability.