ACOUSTIC DEPTH SOUNDER

PURPOSE:To make it possible to easily and accurately detect the depth of water even if there is disturbance, by taking the correlation between an estimated theoretical receiving wave from and an actually obtained receiving wavelength to detect the difference with an estimated value. CONSTITUTION:A correlation processor 9 receiving an estimated theoretical wave form (standard reflected wave form) signal 18 and a receiving signal 6 outputs the correlation signal 19 showing the correlation of input signals 18, 6. A max. correlation detector 10 outputs a depth-of-water signal 21a showing the depth-of-water value of a vertical component on the basis of the correlation shown by the correlation signal 19 and the delay time at the time of the max. correlation. As mentioned above, because the max. value of correlation may be detected by taking correlation, the depth of water can be easily and accurately detected even if the receiving wave form is distorted because of the presence of a disturbance factor.