Forward scatter and backscatter low-frequency synthetic array measurements of the structural acoustic response from proud targets using a 48-m-long rail in a littoral environment.

Abstract

A series of short range (25-m) forward scatter and backscatter measurements in a littoral environment was conducted to quantify the structural acoustic response from proud targets in the 2–23 kHz frequency band. The water channel was 14 m deep in the Gulf of Mexico near Shell Island, Panama City FL. The bottom was a medium grained sand. The acoustic forward scatter response of the proud targets was measured in a bistatic configuration with the source 25 m from the target and a receiver mounted on a 48-m-long rail. The rail is used to position the receiver and synthetically quantify the structural acoustic forward scatter response. A second source was co-located with the receiver on the rail, and monostatic backscatter measurements were also taken for each target. The structural acoustic response was analyzed and will be reported. The synthetic array experimental results are compared and contrasted with laboratory measurements. The laboratory measurements are convolved with water channel propagation predictions using a parabolic equation model of the littoral environment. The convolved laboratory target strengths compare well with the synthetic array measurements, and a detailed discussion of the comparison will be presented. [Work supported by ONR.]