Accession Number : ADA303052

Title :   Estimation of Bottom Scattering Strength from Measured and Modeled AN/SQS-53C Reverbation Levels.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Scanlon, Gary A.

PDF Url : ADA303052

Report Date : JUN 1995

Pagination or Media Count : 204

Abstract : Hamilton type geoacoustic models were developed for Area Foxtrot, a NUWC test bed for emerging active sonar systems where the surface sediment type is highly spatially variable. Reverberation levels (RL) were modeled using the FEPE propagation model to augment the GSM propagation model because the bottom loss model in GSM did not estimate transmission loss accurately in shallow water. FEPE estimates reveal there is over a 15 dB difference between TL for sand and silt-clay sediments in Area Foxtrot. The comparison between modeled RL and measured RL (from a 1991 ASW exercise conducted by MUWC) enabled bottom scattering strength kernels to be developed for Area Foxtrot Bottom scattering strength was found to be a function of sediment type. Hard sand sediment has a bottom scattering strength which obeys Lambert's law (sin2 (theta)) while that of silt clay sediment is consistent with volume scattering (sin (theta)). The RLs in Area Foxtrot are azimuth-dependent and are a function of TL and bottom scattering strength (and hence bottom sediment type). Sonar beams steered towards the hard sand show higher

Descriptors :   *ACOUSTIC SCATTERING, *REVERBERATION, *BOTTOM LOSS, TEST BEDS, THESES, SAND, SHALLOW WATER, CLAY, SONAR, SEDIMENTS, OCEAN BOTTOM SOILS, TRANSMISSION LOSS, UNDERWATER SOUND SIGNALS, SILT, SOIL MODELS.

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE