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首页> 美国政府科技报告 >Fish School Target Strength and Doppler Measurements.
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Fish School Target Strength and Doppler Measurements.

机译：鱼群目标强度和多普勒测量。

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A study of the acoustic characteristics of fish schools necessary to establish engineering parameters for the design of acoustic systems for the Navy was undertaken. Target strengths of 10,534fish schools in the California Current System (CCS) were measured. For pulse durations of 10milliseconds,the average target strength was -7.3decibels with a standard deviation of 5.3and the average target strength for intensity was -2.4decibels. Of all schools 73% had target strengths greater than or equal to -10decibels;no values greater than 20decibels were measured. Peak target strength was found to be both pulse length and range dependent. Although the Doppler data were considered to be preliminary, 32% of the 260schools examined displayed speeds greater than or equal to 1knot. No ship avoidance by the schools was observed,and no speeds greater than 5knots were recorded. Schools size varied in extent from 5to 250meters,measured acoustically along the axis of the sound cone. The mean target extent was 64meters with a standard deviation of 42meters; a strong mode existed at 35meters.

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