| 摘要 |
<p>In a method and apparatus for surveying for nodular targets of a grain size of 1 to 15 cm present on the sea floor, pulse waves in each of three frequency ranges of 3 to 4, 10 to 14 and 25 to 50 KHz are radiated onto the sea floor from a ship navigating on the sea. The reflected sound waves of the three frequency pulse waves are received and the reflexibilities of the respective sound waves are measured from the reflected sound pressures and the reflexibilities are composed. The population of the nodular targets is determined from the composed reflexibility and, as required, the grain size of the nodular targets can be determined from at least one of the ratio of the reflexibility of the sound waves of the frequency range of 3 to 4 KHz to the composed reflexibility and the ratio of the reflexibility of the sound waves of the frequency range of 3 to 4 KHz to the reflexibility of the sound waves of range of 25 to 50 KHz.</p> |
