DPSD algorithm for AC magnetic tracking system

6 DOF (degree-of-freedom) tracking system is one of the key device to realize the sense of immersion and human computer interaction in a VR or AR (Virtual or Augmented Reality) system. This paper presents the design of an AC magnetic tracking system and a DPSD (digital phase sensitive detector) algorithm to extract the received signals. The proposed magnetic tracking system is composed of 3-axis orthogonal magnetic sensor, 3-axis orthogonal magnetic transmitter, 2-axis accelerometers, data acquisition and processing system etc. After obtaining the orientation of the receiver by measuring the Earth magnetic and gravity field with the DC output of magnetic sensors and accelerometers, the position of the receiver can be calculated from the received AC magnetic field generated by the magnetic transmitter. The performance of the existing DPSD algorithm when being used to extract the received AM (amplitude modulation) signals is studied and a new DPSD algorithm as well as its performance are presented. Experimental results show that the proposed algorithm can be used to measure the AM signal embedded in background noise and the feasibility of its application in the AC magnetic tracking system.