Fleet Oceanographic And Acoustic Reference Manual



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Fleet oceanographic and acoustic reference manual secnavinst 5510.36 department of the navy (don) information security program regulation bupersinst 1430.17 command advancement program bupersinst 1610.10 navy performance evaluation and counseling system; encl 1, 2 joint pub 3-07.2. Fleet Oceanographic and Acoustic Reference Manual, RP 33, Naval. 2 Eras of Oceanographic Exploration. Rp-33 oceanography manual 5 The Role of Observations in Oceanography. Dents in meteorology, ocean engineering, and oceanography.

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Passive Sonar Equation

In passive-sonar operations, the hydrophorespickup sounds generated by a multitude of soundsources.Sonarmen must differentiate betweensoundsgenerated by a target and interferingbackgroundnoise. This process is best describedinwhat is known as the passive sonar equation.Thepassive form of the sonar equation, like theactiveform, is written using several differentsymbolsto represent the equation parameters.Oneform of the equation is as follows:

SIGNAL EXCESS. —Signal excess has thesamemeaning in the passive equation that it doesinthe active equation.

SOURCE LEVEL. —Source level pertains totarget-radiatednoise. It is the amount of soundenergygenerated by a target. The level of energyreachingthe sonar receiver depends on the typeoftarget and its mode of operation. Source levelisa function of frequency, speed, depth, andtargetaspect. The latter refers to a target’sorientationin relation to the sonar receiver.

RECOGNITION DIFFERENTIAL. —RDhasthe same meaning as in the active sonarequation.

NOISE LEVEL. —The definition for NL inthepassive equation is the same as in the activeequation.Passive sonars may be ambient-noiseorself-noise limited. These sonars lessen the noiseincertain frequency ranges, thereby permittingatarget signal to be more readily detected.

Ambient Noise. —Ambient noise is thatpartof the total background noise created bysurface-shiptraffic, wave action, precipitation,ice,and certain forms of marine life.

Self Noise. —Self noise is that part of the totalbackgroundnoise attributable to the sonar equip-ment,theplatform on which it is mounted, or thenoisecaused by the motion of the platform. Themajorclasses of self-noise are machinery noise,propellernoise, and hydrodynamic noise. Thelatterresults from the flow of water pasthydrophores,supports, and the hull structure oftheplatform.

DIRECTIVITY INDEX. —DI has the samemeaningas in the active sonar equation.

PROPAGATION LOSS. —PL has thesamemeaning as in the active sonar equationexceptthat with passive sonar, the energy loss isone-way.

References

Fleet Oceanographic and Acoustic ReferenceManual, RP-33, Naval Oceanographic Office,July1986.

Fleet Oceanographic And Acoustic Reference Manual Pdf

Operational Oceanography Module II, AcousticsandSound Ray Theory, NOCF Bay St. Louis,Miss.,1988.

Fleet Oceanographic And Acoustic Reference Manual Pdf

Acoustic

Rp 33 Fleet Oceanographic Pdf

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