Using natural footstep-accurate traces for indoor positioning evaluation

In this paper, an evaluation method using natural footstep-accurate traces as ground truth is proposed. Said ground truth was obtained by video-taping people who were naturally walking in the foyer of our company building. These video-clips were then manually analyzed, using the tiles of the foyer's floor as a coordinate system. The result of this analysis are not simply the positions of the filmed users as they progress through the foyer, but the coordinates of each single footstep of each user including timestamps for each step. To evaluate the position accuracy of an indoor positioning system, these traces were laid out on the floor and `re-walked' while carrying the hardware for the positioning system. A short sound was played according to the timestamps of each recorded step of the ground truth, to ensure that the walking speed was close to the real walking speed. The distances of these `target system traces' to the ground-truth traces were then calculated and analyzed.