To accurately estimate the target distance and azimuth when the acoustic sound is the search sound.
When the acoustic sound emitted from the objective by a search sound detector 4 is the search sound, an azimuth detecting unit 6 reads out received signals received by staves 12a, 12b from received signal buffers 32a, 32b and estimates the target azimuth a from the maximum value of the correlation function R21(α). Rough propagation time lag estimating units 71, 72 estimate the rough propagation time delay D21* between wave receiver arrays 12, 11 and the rough propagation time lag D32* between wave receiver arrays 13, 12 on the basis of the azimuth α. Propagation time lag estimating units 81, 82 find the maximum value of the curve including the rough propagation time lag D*21, D*32 with respect to the correlation functions R21*(τ), R32*(r), and the maximum valve is estimated as the propagation time lag D21, D31. A target distance estimating unit 9 and a target azimuth estimating unit 10 respectively found the target distance and azimuth on the basis of the propagation time lag D21, D32.
MIZOTA TORU
OZAKI SHUNJI
OKITA YOSHIO
