Sound beam scanning in sediment layer using phase conjugated pseudo sound source

Acoustical Science and Technology

Yoshiaki Tsurugaya⁴  Ryoichi Iwase²  Toshiaki Kikuchi¹  Koichi Mizutani³ 

[1] National Defense Academy;JAMSTEC (Japan Agency for Marine-earth Science and TEChnology);University of Tsukuba;NEC Corporation

关键词: Phase conjugate;    Buried object;    Pulse compression;    Pseudo sound source;   

DOI  :  10.1250/ast.29.9

学科分类：声学和超声波

来源: Acoustical Society of Japan

【 摘 要 】

References(7)Cited-By(2)When an object that is buried underwater in a sediment layer is detected from the diagonal, detection is often hampered by reflection from the bottom surface. Stated in different terms, the sound-wave energy that reaches the object is small because of reflection and refraction that occurs at the bottom surface when a sound wave is applied to the object in the sediment for diagonal detection. To alleviate that problem, a pseudo sound source can be set up in the sediment layer. The sound wave radiated from the pseudo sound source is then received by a time-reversal array. The sound wave can be injected into the sediment layer by reversing the received signal with time, and radiating it again from the time-reversal array. The beam can hit the target through movement of this pseudo sound source along the bottom surface. The sound wave that hits the target is reflected and returns in water. The sound wave is subsequently reflected many times at the surface and bottom, and is diffused over time. The passive-phase conjugate processing is then given to the received diffusing signal to reduce this diffusion. The pulse is compressed by this processing, thereby obtaining the target position.

【 授权许可】

Unknown