摘要：Dolphins have a very sophisticated short range sonar that surpass all technological sonar in its capabilities to perform complex target discrimination and recognition tasks. The system that the U.S. Navy has for detecting mines buried under ocean sediment is one that uses Atlantic bottlenose dolphins. However, close examination of the dolphin sonar system will reveal that the dolphin acoustic “hardware” is fairly ordinary and not very special. The transmitted signals have peak-to-peak amplitudes as high as 225 - 228 dB re 1 ?Pa which translate to an rms value of approximately 210 - 213 dB. The transmit beamwidth is fairly broad at about 10o in both the horizontal and vertical planes and the receiving beamwidth is slightly broader by several degrees. The auditory filters are not very narrow with Q values of about 8.4. Despite these fairly ordinary features of the acoustic system, these animals still demonstrate very unusual and astonishing capabilities. The dolphin biosonar system will be discussed from the perspective of a technological sonar system consisting of a signal projection section including signal generation, propagation through the head and directivity index, a reception section including receiving sensitivity, directivity, and internal filtering process, and a signal processing section.
Some of the capabilities of the dolphin sonar system will be presented and the reasons for their keen sonar capabilities such as discriminating and recognizing different fish species, differences in wall thickness of metal cylinders and differences in the composition of metallic targets will be discussed. Important features of their sonar include the broadband click-like signals used, adaptive sonar search capabilities and large dynamic range of its auditory system.
专家简介：Whitlow W.L Au教授是夏威夷大学海洋生物研究所海洋哺乳动物研究项目首席科学家，是世界鲸豚生物声纳研究领域的权威专家，在国际上享有极高的知名度。1998年他因对海豚声纳基础声学的卓越贡献而荣获美国声学学会动物声学银奖（该奖项设立以来首位获奖人）。此外，他长期担任《美国声学学会杂志》、《动物生物声学》等杂志的副主编，还曾担任美国声学学会理事长，美国声学学会、动物声学技术委员会联合主席。在学术成果方面，他曾出版过3本关于海洋哺乳动物声学研究的著作及多达数百篇学术论文，其中他的专著《The Sonar of Dolphins》已成为海豚生物声纳领域的经典著作。