Measuring Angular Variation of Target Strength for Simple Geometric ObjectsCDR Ed TucholskiUS Naval AcademyAnnapolis, MD

Active Sonar EquationsNoise Limited CaseReverberation Limited CaseFunction of geometry and scattering direction

Target StrengthThe reflected intensity (pressure) is dependent on the reflection, diffraction, and interference of sound scattered off the object. Target Strength is highly dependent on the scattering angle.The teaching point of this demonstration is to show the angular dependence. For simplicity, we will measure

ApparatusData AcquisitionSerial to USBTekVisaExcelTransducers

Envelope Detector

Square Plate

Circular Plate

CylinderL

Cylinder 360o Target Strength

Target Strength is a Decibel

Demonstration

SettingsWavetek Model 29Sine 40.04 kHz18.1 V p-pSR560Source A, AC Coupled6 dB/oct band pass, 10k-100k HZLow NoiseGain = 20

Scope 1Ch 1 10 V/divCh 2 50 mV/divt = 10.0 msScope 2Ch 2 100 mV/divt = 4.00 sVXM-1 72 s/rev