(a) a storage device storing position association unique information associating position coordinates and unique information indicating a unique feature amount associated with the position coordinates;

(b) a transmission device transmitting a detection signal assigned identification information;

(c) a reception device receiving a reflection signal corresponding to the detection signal transmitted by said transmission device;

(d) a generation device generating signal unique information based on a unique position from the reflection signal received by said reception device; and

(e) an identification device comparing between the signal unique information generated by said generation device and the unique information associated with the position coordinates included in the position association unique information and indentifying a current position,

wherein:

(f) said identification device compares between the signal unique information generated by said generation device and the unique information included in the position association unique information stored in said storage device;

(g) the identification device calculates the correlation value indicating the correlation between the position coordinates associated with the unique information and the current position;

(h) the identification identifies the current position based on the calculated correlation value:

(i) said identification device complements a correlation value at a position different from the position coordinates from the calculated correlation value;

(j) the identification device calculates a distribution of the correlation values corresponding to the position coordinates; and

(k) the identification device identifies the crest of the distribution of the correlation values as the current position.