  We propose an indoor navigation algorithm based on pedestrian dead reckoning
(PDR) using an inertial measurement unit in a smartphone and map matching. The
proposed indoor navigation system is user-friendly and convenient because it
requires no additional device except a smartphone and works with a pedestrian
in a casual posture who is walking with a smartphone in their hand. Because the
performance of the PDR decreases over time, we greatly reduced the position
error of the trajectory estimated by PDR using a map matching method with a
known indoor map. To verify the proposed indoor navigation algorithm, we
conducted an experiment in a real indoor environment using a commercial Android
smartphone. The performance of our algorithm was demonstrated through the
results of the experiment.
