Hsb 2011 diffuse

Low Frequency Sound Technologies HSB Workshop, Rotterdam, 10/11/2011, Frederic Mosca, PhD

Contents ,[object Object],[object Object],[object Object],[object Object]

IXSEA Overview ,[object Object],[object Object],SYSTEMS SOLUTIONS PRODUCTS TECHNOLOGIES

IXSEA Products and Technologies ,[object Object],[object Object],[object Object],[object Object],[object Object]

Acoustic Research & Technology ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Low Frequency Sound Technology Low Frequency 0.1 kHz 1 kHz 10 kHz 100 kHz 1000 kHz 1000 km 100 km 10 km 1 km 0.1 km Seismic Subbottom Profilers Passive Military Sonars Active Military Sonars Transmission and Positionning Imaging Sonar (SSS, SAS) MultiBeam Echo Sounder Fishery Echo Sounders and Sonars Acoustic Camera

High Resolution Seismic Reflection ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

High Resolution Seismic Reflection: Principle Platform Trajectory Water Column Signal enveloppe Seismic profile Ref. X.Lurton, An introduction to Underwater Acoustics

High Resolution Seismic Reflection: Theory ,[object Object],[object Object],[object Object],At each interface an echo is generated Medium 1 Medium 2 p i p t p r

High Resolution Seismic Reflection: Theory ,[object Object],[object Object],[object Object],Medium 1 Medium 2 p i p t p r h θ

High Resolution Seismic Reflection: key parameters ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

High Resolution Seismic Reflection: key parameters ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Work near the bottom Solid state source

High Resolution Seismic Reflection: key parameters ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Working at low frequency

High Resolution Seismic Reflection: key parameters ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

High Resolution Seismic Reflection: Linear System Theory ,[object Object],Source Function Medium Function Sediment column Dirac comb

High Resolution Seismic Reflection: Source spectrum effect ,[object Object],Sediment column Absorption Ideally flat BW source F t Sediment column Absorption Real source F t

High Resolution Seismic Reflection: Image quality ,[object Object],[object Object],SL Source Level Spectrum F SL max SL max -3dB B A 0 A 0 /2 A t T A s

High Resolution Seismic Reflection: Intrinsic tradeoff ,[object Object],[object Object],[object Object],[object Object]

High Resolution Seismic Reflection: Sound technologies ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Ref. Woods Hole University website Air Gun Principle Ref. Woods Hole University website

High Resolution Seismic Reflection: Sound technologies Impulsive source Resonant source Poor Performance… … but strong potential Ref. Verbeek et al. (1995) ; Moscher et al. (1999) Boomer Airgun Sparker Piezoelectric Energy output High (230dB) High (235dB) Medium (225dB) Low (215dB) Typical BW 0.5-5kHz 20-300Hz 0.5-5kHz Q = 10% Arbitrary WF No No No Yes Directivity Yes No No Yes Repeatability High Poor Poor High Deep-tow Capability No No <1000m Full depth Other Bubble pulse Bubble pulse

High Resolution Seismic Reflection: Chirp technology ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],c/2B B.T

High Resolution Seismic Reflection: Chirp technology Sediment column Absorption Pulse source F t Sediment column Absorption Chirp source F Better penetration

High Resolution Seismic Reflection: Chirp technology ,[object Object],[object Object],How increasing Q ? Boomer Airgun Sparker Piezoelectric Energy output High (230dB) High (235dB) Medium (225dB) High (235dB) After pulse compression Typical BW 0.5-5kHz 20-300Hz 0.5-5kHz Q = 10% Arbitrary WF No No No Yes Directivity Yes No No Yes Repeatability High Poor Poor High Deep-tow Capability No No <1000m Full depth Other Bubble pulse Bubble pulse

Low Frequency Sound Technology: Coupled resonator

Low Frequency Sound Technology: Design Process ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Low Frequency Sound Technology: Flapping Tonpilz ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Q = 100% High SL Depth limited

Low Frequency Sound Technology: Janus-Helmholtz ,[object Object],[object Object],[object Object],[object Object],[object Object],Q = 100% Full Depth Medium SL

Low Frequency Sound Technology: Bandwidth Flatness ,[object Object]

Low Frequency Sound Technology: Transmission Chain Power Amplifier Transducer Waveform Generator Power Supply Impedance Matching 10dB

Low Frequency Sound Technology: Transmission Chain Power Amplifier Transducer Waveform Generator Power Supply Impedance Matching 3dB Compensation Stage

High Resolution Seismic Reflection: Sound technologies Boomer Airgun Sparker Flapping Tonpilz Janus-Helmholtz Energy output High (230dB) High (235dB) Medium (225dB) High (235dB) After pulse compression Medium (225dB) After pulse compression Typical BW 0.5-5kHz 20-300Hz 0.5-5kHz Q = 100% Q = 100% Arbitrary WF No No No Yes Yes Directivity Yes No No Yes No Repeatability High Poor Poor High High Deep-tow Capability No No <1000m No Full Depth Other Bubble pulse Bubble pulse Bad Weather Operability

High Resolution Seismic Reflection: ECHOES Family 600Hz 1500 Hz 3500 Hz 5000 Hz 10000 Hz

ECHOES 1500 : Description ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],GAPS Beacon GPS Underwater Housing (power supply, synchro, com’ ) Phins 6000 Echoes 1500 6000m

ECHOES 1500 : Results 55ms 145ms 400m 40cm resolution

ECHOES 3500 : Description ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

ECHOES 3500: Results 605ms 870ms 150m penetration

ECHOES 5000: Description ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

ECHOES 10000: Description ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

ECHOES 10000: Results 0ms 25ms 4m

ECHOES 10000 vs ECHOES 5000 10kHZ 5kHZ

Conclusion and further research ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],100bits/s @ 1000km DSS0 – 10dB

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