To enable position estimation in only a small number of base stations.
One sound wave base station 3 transmits sound waves in a pulse line in accordance with a predetermined transmission interval and pulse information. Swing motion is applied to a user terminal 1, and a swing detection part 16 detects a swing section from the acquisition direction of a direction sensor part 15. A sound wave receiving part 12 receives the sound waves, and an interval calculation part 14 calculates reception interval of the sound waves in the swing section. A direction estimation part 17 estimates the direction of the sound wave base station 3 during the swing using the principal similar to the Doppler effect on the basis of a difference between a predetermined transmission interval and a predetermined reception interval. A distance estimation part 18 estimates a distance to the sound wave base station 3. On the basis of the estimated direction and distance, a position estimation part 19 estimates a position of the user terminal 1 to the sound wave base station 3 whose position is known.
YOSHIHARA TAKAHITO
Kaori Tanaka
Sanji Tanabe
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