Versatile Echo Sounding System Using Dual Beam.
Masahiko Furusawa, Yoshimi Takao, Koichi Sawada, Terushi Okubo, Kyozo Yamatani · NIPPON SUISAN GAKKAISHI · 1993
A versatile quantitative echo sounding system using dual beam has been developed for acoustic surveys of fishey resources.Some new techniques were applied to this system to improve accuracy and precision in estimating fish abundance.The transmitting and receiving system was designed under the principle of minimum errors.Absolute echo levels can be measured by a paper recorder and by a color display facilitating a quantitative understanding of targets.The dual beam signals are utilized not only for target strength measurement, but also for schooling density observation and for echo integration.The sounder has been successfully used for walleye pollock Theragra chalcogramma surveys in the Bering Sea.