Kongsberg Simrad EK80 - Acoustic Noise; Contributing Factors

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Acousticnoise
Aswithanyotherhydroacousticsystems,thequalityoftheEK80echodataand
presentationsaresubjecttounwantedacousticnoise.Theechoesfromanylargeand
smalltargetmustbedetectedinsidethenoise.
Itisimportantthatwekeepthenoiselevelaslowaspossible.Thisisnecessarytoobtain
longrangeanddependableinterpretationsoftheechoes.Evenwiththeadvancednoise
lteringofferedbytheEK80,wemustaddressthenoisechallenge.Thisisimportant
duringtheplanningandpreparationsfortheEK80installation.
Topics
Contributingfactors,page54
Selfnoise,page56
Ambientnoise,page58
Fishinggearnoise,page59
Electricalselfnoise,page59
Somemeanstoreduceacousticnoise,page59
Contributingfactors
Severalfactorsarecontributingtotheperformanceofthehydroacousticequipment
usedonboardavessel.
Factorscontributingtotheperformanceofthehydroacousticequipmentusedonboarda
vesselare:
•Thequalityandpropertiesofthetransmittedsignal
•Thequalityofthereceivingsystem
•Theoperationalsettingsmadeduringoperation
•Thepropertiesofthetarget(s)
•Thesignal-to-noiseratio
Themajorityofthesefactorscanneitherbecontrollednorimprovedbymeans
ofinstallationmethodsortransducerlocations.Thequalityandpropertiesofthe
transmittingandreceivingsystemsarekeyfactorsduringourproductdevelopment,while
ourenduserdocumentationaimstohelptheusertomaketherightltersettingsduring
operation.Asforthetargetproperties,thereisnothinganyofuscandowiththose.
Thesignal-to-noiseratio,however,canbeimprovedbymakingthecorrectchoices
duringinstallation.
Signal-to-noiseratio(oftenabbreviatedSNRorS/N)isameasureusedin
scienceandengineeringthatcomparesthelevelofadesiredsignaltothelevelof
backgroundnoise.Itisdenedastheratioofsignalpowertothenoisepower,often
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