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processing system of the sonar. The SURTASS hydrophones are mounted on a horizontal receive array that is towed behind the vessel. The array length is 1,500 m (4,900 ft) with an operational depth of 150 to 460 m (500 to 1,500 ft). The SURTASS LFA ship must maintain a minimum speed of approximately 6 kilometres per hour (3.2 knots) through the water in order to tow the hydrophone array in the horizontal plane. The return signals or echoes, which are usually below background or
635:
263:
The typical LFA transmitted sonar signal is not a constant tone, but a transmission of various waveforms that vary in frequency and duration. A complete sequence of transmissions is referred to as a ping and lasts from 6 to 100 seconds, although the duration of each continuous frequency transmission
240:
The active system component, LFA, is an adjunct to the passive detection system, SURTASS, and is planned for use when passive system performance proves inadequate. LFA is a set of acoustic transmitting source elements suspended by cable from underneath a ship. These elements, called projectors, are
148:
As the passive systems were being deployed, an active adjunct known as the SURTASS Low
Frequency Active (LFA) systems was designed for long range detection. The active system must be used in conjunction with the passive received system. The active component transmits an audio signal between 100 Hz
274:
The passive, or listening, part of the system is SURTASS, which detects returning echoes from submerged objects, such as submarines, through the use of hydrophones. These devices transform mechanical energy (received acoustic sound wave) to an electrical signal that can be analyzed by the signal
248:
The source is a vertical line array (VLA) of up to 18 source projectors suspended below the vessel. LFA’s transmitted sonar beam is omnidirectional (i.e., a full 360 degrees) in the horizontal (nominal depth of the LFA array center is 120 m ), with a narrow vertical beamwidth that can be steered
161:. In 1996 the Navy published a notice of intent to prepare an environmental impact statement. The Navy has spent over $ 16 million on scientific research on the effects on marine mammals and mitigation systems as well as the development of an Environmental Impact Statement.
252:
The source frequency is between 100 and 500 Hz (the LFA system’s physical design does not allow for transmissions below 100 Hz). A variety of signal types can be used, including continuous wave (CW) and frequency-modulated (FM) signals. Signal bandwidth is approximately 30
149:
and 500 Hz from an array suspended below the ship while the passive SURTASS array is towed miles behind to receive the signal after it had reflected off the submarine. The active LFA system is an updated version of the fixed low frequency surveillance system known as
82:
SURTASS Twin-Line consists of either the long passive SURTASS array or the Twin-line array, consisting of two shorter passive arrays towed side by side. The Twin-line
Engineering Development Model was installed on
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241:
devices that produce the active sound pulse, or ping. The projectors transform electrical energy to mechanical energy that set up vibrations or pressure disturbances within the water to produce a ping.
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Duty cycles (ratio of sound “on” time to total time) are less than 20 percent—20 percent is the maximum physical limit of the LFA system. Typical duty cycles are approximately 7.5 to 10 percent.
861:
145:. Initially the SURTASS system were passive, receiving only sonar systems. The array was towed miles behind the ships and were designed for long range detection of submarines.
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SURTASS LFA is a long-range, all-weather, sonar system with both passive and active components, operating in the low frequency (LF) band (100–500 hertz ). USNS
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conducted five training missions in the
Philippine Sea and the northwest Pacific Ocean. All LFA sonar operations included the operation of the
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291:, low frequency active sonar fitted to British warships, the CAPTAS4 derivative is being tested by the US Navy
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had the first contract awarded on 26 September 1980 and were similar to the prototype ship, the
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279:, are then processed and evaluated to identify and classify potential underwater targets.
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The ship had five years of active and passive operations in the
Western Pacific before an
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NOAA National Marine
Fisheries Service Office of Protected Resources SURTASS LFA page
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173:, commenced sea trials in late February 2004. During the spring and summer of 2004,
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153:. Although the Navy took steps to mitigate the environmental damage, environmental
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195:(August 15, 2005 to August 15, 2006) 22.5 days with 39.4 hours of transmissions
192:(August 15, 2004 to August 15, 2005) 9.4 days with 22.7 hours of transmissions
189:(August 15, 2003 to August 15, 2004) 26.2 days with 63.0 hours of transmissions
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M. A. Ainslie, Principles of Sonar
Performance Modeling (Springer, 2010), p522
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The source level (SL) of an individual source projector is approximately 215
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SURTASS began as development program in 1973 using the new research vessel
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as originally configured. Aft view of equipment for the
Surveillance
221:; the 64-tonne Compact LFA derivative was developed for the smaller
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Total operational days on board the
Impeccable using the LFA array:
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385:"Federal Register: August 25, 2005 (Volume 70, Number 164)"
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The time between pings is typically from 6 to 15 minutes.
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The characteristics and operating features of LFA are:
68:), colloquially referred to as the ship's "Tail", is a
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sonar and compliance with all mitigation requirements.
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740:
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90:, and the first production model was installed on
717:Ultra-short baseline acoustic positioning system
237:in 2012; no further installations are planned.
217:has the original LFA system, weighing 155
62:AN/UQQ-2 Surveillance Towed Array Sensor System
862:Military sonar equipment of the United States
518:
100:As of 2009, SURTASS was deployed on the four
97:. Neither ship still serve as SURTASS units.
8:
692:Short baseline acoustic positioning system
525:
511:
503:
157:(NGOs) urged the Navy to prepare a public
56:(T-AGOS-20) aft view of SURTASS equipment.
867:Military electronics of the United States
682:Long baseline acoustic positioning system
335:"Military Sealift Command Ship Inventory"
310:"2002 Edition: Vision...Presence...Power"
179:High Frequency / Marine Mammal Mitigation
301:
732:Underwater acoustic positioning system
610:Surveillance Towed Array Sensor System
7:
493:SURTASS Twinline and LFA information
872:Equipment of the United States Navy
25:
727:Underwater acoustic communication
662:Acoustic Doppler current profiler
483:Federation of American Scientists
439:"SURTASS LFA FINAL REPORT page 9"
633:
264:is never longer than 10 seconds.
785:Hearing range of marine mammals
451:from the original on 2017-01-28
411:from the original on 2017-01-28
202:incident in the South China Sea
139:-class ocean surveillance ships
116:small-waterplane-area twin hull
667:Acoustic seabed classification
249:above or below the horizontal.
159:environmental impact statement
155:non-governmental organizations
44:Sensor System (SURTASS), 1987.
1:
225:class. CLFA was installed on
888:
750:Acoustic survey in fishing
399:"SURTASS/LFA Final Report"
167:Low Frequency Active Sonar
687:Ocean acoustic tomography
631:
498:Moana Wave specifications
130:. In 1980 SURTASS passed
790:Marine mammals and sonar
615:Synthetic aperture sonar
27:Towed array sonar system
672:Acoustical oceanography
106:-class vessels and the
590:Scientific echosounder
57:
45:
770:Deep scattering layer
580:Multibeam echosounder
575:GLORIA sidescan sonar
51:
33:
722:Underwater acoustics
712:Sound velocity probe
707:Sound speed gradient
625:Upward looking sonar
570:Fessenden oscillator
473:USN SURTASS LFA page
831:Hydrographic survey
780:Fisheries acoustics
760:Animal echolocation
555:Baffles (submarine)
277:ambient noise level
826:Geophysical MASINT
811:Acoustic signature
478:GlobalSecurity.org
77:United States Navy
58:
46:
849:
848:
620:Towed array sonar
600:Sonar beamforming
585:Passive acoustics
169:system, on board
118:(SWATH) vessel).
112: (T-AGOS-23)
16:(Redirected from
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742:Acoustic ecology
657:Acoustic release
652:Acoustic network
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550:Active acoustics
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362:. Archived from
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337:. Archived from
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260:(dB re 1 ÎĽPa m).
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804:Related topics
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702:SOFAR channel
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366:on 2013-09-28
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360:"Surtass Lfa"
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816:Bioacoustics
755:Acoustic tag
453:. Retrieved
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413:. Retrieved
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368:. Retrieved
364:the original
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343:. Retrieved
339:the original
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233:in 2011 and
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209:Description
70:towed array
42:Towed-Array
856:Categories
841:Soundscape
795:Whale song
775:Fishfinder
697:Sofar bomb
677:Hydrophone
455:2009-03-28
415:2009-03-28
370:2006-12-30
345:2006-12-30
320:2006-12-28
296:References
289:Sonar 2087
235:Victorious
223:Victorious
215:Impeccable
175:Impeccable
171:Impeccable
143:Moana Wave
134:. The new
128:Moana Wave
110:Impeccable
108:USNS
103:Victorious
37:Invincible
836:Noise map
231:Effective
87:Assertive
821:Biophony
605:Sonobuoy
446:Archived
406:Archived
283:See also
258:decibels
137:Stalwart
122:History
66:SURTASS
18:SURTASS
219:tonnes
132:OPEVAL
542:Sonar
449:(PDF)
442:(PDF)
409:(PDF)
402:(PDF)
92:USNS
85:USNS
73:sonar
52:USNS
35:USNS
227:Able
94:Bold
60:The
54:Able
253:Hz.
114:(a
858::
444:.
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519:t
512:v
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64:(
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
