| 摘要 |
<p>PURPOSE:To discriminate acoustic waves from elastic waves in real time on the sea bottom. CONSTITUTION:An acoustic sensor 11 receives wave signals on the sea bottom by means of paired hydrophones arranged at prescribed intervals in parallel with three orthogonal axes. A signal converting section 12 converts received signals into digital signals. A phase processing section 13 finds the arriving time lags of the received signals at the paired hydrophones based on the digitized signals. A speed calculating section 14 calculates the three-dimensional propagating speed of the received signals from the arriving time lags and the arranging intervals of the hydrophones. An arriving direction calculating section 15 calculates the arriving direction of the received signals by using the calculated propagating speed. At the time of calculating the arriving direction, the section 15 finds the true arriving direction by adding the laying direction of the hydrophones detected by means of a direction sensor section 16 to the propagating speed. A signal discriminating section 17 discriminates whether the received signals are underwater acoustic signals or elastic wave signal propagated through the ground by using the calculated propagating speed and arriving direction.</p> |
