180 likes | 367 Views
Measuring Angular Variation of Target Strength for Simple Geometric Objects. CDR Ed Tucholski US Naval Academy Annapolis, MD. Reflected Wave. Object. Transmitter/ Receiver. Original Wave. Distance r. Drawing Source: Wikipedia. Active Sonar Equations.
E N D
Measuring Angular Variation of Target Strength for Simple Geometric Objects CDR Ed Tucholski US Naval Academy Annapolis, MD
Reflected Wave Object Transmitter/ Receiver Original Wave Distance r Drawing Source: Wikipedia Active Sonar Equations Function of geometry and scattering direction Noise Limited Case Reverberation Limited Case
Target Strength The 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
Filter Pre-Amp Target 1.15 cm 0.8 cm Transducers and Positioning System Envelope Detector Motor Controller Signal Generator 40 kHz 25 kHz O-scope O-scope Apparatus • Data Acquisition • Serial to USB • TekVisa • Excel Transducers
- + IN914 Diodes LM741 Operational Amplifier Envelope Detector
a Data Theory Square Plate
a Data Theory Circular Plate
Data Theory Cylinder L
Wavetek Model 29 Sine 40.04 kHz 18.1 V p-p SR560 Source A, AC Coupled 6 dB/oct band pass, 10k-100k HZ Low Noise Gain = 20 Scope 1 Ch 1 10 V/div Ch 2 50 mV/div t = 10.0 ms Scope 2 Ch 2 100 mV/div t = 4.00 s VXM-1 72 s/rev Settings