In this paper, sensor modules which are consisted of a low cost IMU and a magnetic fluxgate are attached to both shoes to build a dual foot PNS. To implement the dual foot PNS, 1) the navigation algorithm for the dual foot PNS is proposed, 2) an accurate and robust step detection algorithm is designed by combining the advantage of the peak detection method and flat zone detection method, 3) two heading estimation methods are applied: the walking zone mean and the supporting zone mean methods. The heading bias from individual walking pattern is effectively compensated in the dual foot PNS, while it is accumulated in the single foot PNS. The experiments with real data show that the supporting zone mean method gives better result in the single foot PNS, but the effect of the heading estimation methods is small or ignorable in the dual foot PNS.

Keywords: IMU, PNS, heading