SONAR Signal Analyser(SSA) Passive SONAR Active SONAR Range Resolution Transducer BeamWidth Transducer Beam Plot Scattering CW Oscillator CTFM SONAR Doppler Formulae Dev & Underwater Sounds SSA Demo…..then click AST Console Main Menu Acoustic Systems Trainer – SONAR R&D Platform Installations Acoustic Spectrum
Acoustic Systems Trainer – SONAR : US Naval Academy – Weapons Engineering : Royal Norwegian Navy-SONAR Engineering : Royal Saudi Naval Force – Saudi Arabia : King Fahd Naval Academy – Saudi Arabia : Alenia Marconi Systems – Dundridge College : HMS Daedalus – RN Fleet Air Arm : HMS Collingwood – RN Maritime Warfare School : Britannia Royal Naval College – Dartmouth : University of Plymouth – Underwater Research : Texas A&M University – Marine Engineering : PLPE Kuala Lumpur - Malaysia : Singapore Navy – ASW School Britannia Royal Naval College
Acoustic Systems Trainer – SONAR R&D Platform Royal Navy – Maritime Warfare School – HMS Collingwood
Acoustic Systems Trainer – SONAR R&D Platform Alenia Marconi Systems – Dundridge College
Acoustic Systems Trainer – SONAR R&D Platform Royal Saudi Navy – Technical Institute Naval Studies Royal Saudi Navy T.I.N.S
Acoustic Systems Trainer King Fahd Naval Academy
Acoustic Systems Trainer – SONAR R&D Platform TAMUG – Texas A&M University Galveston Main Menu
AWG with Burst Oscilloscope Spectrum Analyzer Instrument Task Bar SETUP Default Text Multi Meters Transient Recorder Main Menu SSAMenu SSA Menu SONAR Signal Analyzer (SSA)
Acoustic Spectrum Infra-SonicSonicUltra-Sonic (Audio) 30Hz18kHz 2kHz9kHz12kHz50kHz200kHz Passive Sonar Towed Arrays Long Range Sonar Active Search Sonar Dipping Sonar Torpedoes(Attack) AST Minehunting High Definition Oceanographic Sonar Sonic Regions Main Menu A.U.D.I – Acoustic Underwater Development Instrument
Dual Channel One Shot Memos Cursors Ref Channels Multi Trigger Maths Auto Set-up Configurable Peak-Peak RMS Mean Crest Frequency Maths Auto Freq.. Over 190 days Ref Channels Cursors Scroll Scan Memos Zoom Var Axis Dual Ch. Log Scale Averaging Cursors Windows Memos Harmonic Analyzer Exit Sine Triangle Square DC White Noise Sweep Symmetry Attenuation Instrument Configuration Text Colours Start-up CAL files Duty Cycle Directories SSA MenuMain Menu SSA Instrument Task Bar
Main Menu Function Generator AWG + Burst SSA Menu
SETUP Colors Duty Cycle Default Text Active Instruments Main MenuSSA Menu
Main Menu Doppler The Doppler effect is the frequency shift which occurs when a signal is transmitted from a moving platform towards a receiver, conversely, the transmitter could be stationary and the receiver could be in motion. In the most complex case, both transmitter and receiver could be moving with respect to each other. Whatever the case, there is a resultant change in frequency which can be detected and used to determine the speed and direction of motion. The following set-up is one method to enable the Doppler component to be extracted from a moving target echo. Use the Transient Recorder with the output from the Detector to record the Doppler shift.
Movie Doppler Observe the Phase change of the Doppler signal when the target changes direction, and the change in Signal Level as the target opens and closes
Doppler DC Coupling .04 Secs 1,000 Samples 20V Sensitivity. Notes AUX O/P GAIN <50% TX2 O/P GAIN <50% Detector IN/OUT ? Align Receiver Vary Speed/Direction OUTIN CW TransmitterReceiver Detector Main Menu
Range Resolution Movie Observe how both targets are resolved with optimum Pulse Width, and poor target discrimination with increasing PW.
Range Resolution Notes Align ‘Grill’ Target Observe Two Echoes Vary PRF/PW Reversible TX/RXGrill Target SCOPE Main Menu
Active SONAR Movie Observe the Transducer Ringdown, and the smaller amplitude echoes which appear to ‘follow’ the large target echo.
Active SONAR Movie Observe how Pulse Width + Ringdown Time determines the Minimum Range, and the Pulse Repetition Frequency or PRF, sets Maximum Range of the SONAR.
Active SONAR Notes Align Small Target Vary Speed/Direction Identify Echoes Vary PRF/PW/TX FREQ Reversible TX/RXTarget SCOPE Main Menu
Passive SONAR (Pulse) Movie Observe how the Active SONAR transmission, and the Target Echo are detected by the Passive SONAR Hydrophone.
Projector TXHydrophone RX Passive SONAR (Pulse) Notes Align TX and Hydrophone Vary TX FREQ See Spectrum Analyzer SCOPE Main Menu
Beam Plot Movie Observe the smaller Sidelobes either side of the Mainlobes. These manual plots are only intended to give an approximation of the transducer’s Beam Pattern. See the NPL Plot on the next screen which was recorded in a very large, acoustically damped tank under ideal conditions.
National Physical Laboratory Transducer Polar Plot – 192kHz BW = 8º at-3dB Main Lobe Side Lobes
Beam Plot DC Coupling .04 Secs 1,000 Samples 20V Sensitivity. Notes Acoustic Damping AUX O/P GAIN <50% Detector IN/OUT ? Rotate Test Transducer… CW…then CCW OUTIN Detector ProjectorTest Transducer Rotate Handle Acoustic Damping Main Menu
Beam Width Notes Acoustic Damping Observe Spectrum Analyzer Slide Test Transducer… Set 0dB Slide to first –3dB point… Back to 0dB… Slide to second –3dB point Calculate BW CW Signal SourceTest Transducer Acoustic Damping SPECTRUM
Spectrogram Underwater Sound Analysis Main Menu Dolphins Movie
Main Menu Formulae Power Gain = 10 log 10 Pout decibels Pin Passive SONAR equation SE = (SL-PL) – N - DT Active SONAR equation SE = (SL+TS-2PL) – N - DT Speed of Sound in Sea Water (Wilson) C = 1449+4.6T-0.055T 2 +0.0003T 3 +(1.39-0.012T)(S-25)+0.017D Doppler Shift f = + 0.69Hz per knot per kHz f = + 1.33Hz per metre per second per kHz See reference text ‘SONAR FOR PRACTISING ENGINEERS’
General Purpose & AUX Amps Array Beam Steering Power Supply Outputs AST Mk VIII Console S ONAR S ignal A nalyzer PRF TX Frequency Pulse Width Controls Echo Threshold Target Speed Controls Main Menu