Active acoustics

Active acoustics

Active Acoustics is a means of measuring the range to an object and its relative size by producing a pulse of sound and measuring the time it takes for an echo to return from the object and the amplitude of the returned echo. The range is calculated as a function of the speed of sound and the time it takes for the echo to return.

Active acoustics is the principle behind SONAR or hydroacoustics for underwater measurements.

Active acoustic split-beam systems are capable of detecting organisms as small as krill, with no limit on upper sizes. Fish position within the ensonified beam can be accurately located in split-beam systems, allowing calculation of target strength, swim speed, and direction of movement. New directions for active acoustics in science include multibeam, multi-frequency, and high frequency imaging systems. While traditional systems have a beam width of 7-12 degrees sampling a slice of the water column, Multibeam systems such as the EM3002 can be used to examine school shape and behavior with a 130 degree beam width. In addition, multibeam systems are used for details bathymetric mapping and bottom typing based on the returned echo from the bottom. By using multiple frequency systems, fish of varying sizes can be differentiated due to resonance frequencies. High frequency systems such as the DIDSON provide camera-like accuracy of targets in the water column or on the bottom.

ee also


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Underwater acoustics — The field of underwater acoustics is closely related to a number of other fields of acoustic study, including sonar, transduction, acoustic signal processing, acoustical oceanography, bioacoustics, and physical acoustics.HistoryUnderwater sound… …   Wikipedia

  • Cali Iz Active — Infobox Album | Name = Cali Iz Active Type = Album Artist = Tha Dogg Pound Released = June 27, 2006 Recorded = 2005 2006 Genre = West Coast hip hop Gangsta rap Length = 68:52 Label = Doggystyle/Koch Producer = David Banner Ryan Leslie L.T. Moe… …   Wikipedia

  • Waveguide (acoustics) — This page is about waveguides for acoustics and sound, for other types of waveguide, see Waveguide An acoustic waveguide is a physical structure for guiding sound waves. Examples One example might be a speaking tube used aboard ships for… …   Wikipedia

  • LARES — For the flag carrier airline of Romania, see TAROM. LARES is an electronic sound enhancement system that uses microprocessors to control multiple loudspeakers and microphones placed around a performance space for the purpose of providing active… …   Wikipedia

  • Hydroacoustics — is a general term for the study and application of sound in water. The term comes from Greek υδρο, water, and ακουστική, acoustics. Hydroacoustics, utilizing SONAR technology, is most commonly used for detection, assessment, and monitoring of… …   Wikipedia

  • LFAA — Land Force Atlantic Area (Governmental » Military) ** Land Forces Atlantic Area (Governmental » Military) * Lone Fathers Association Of Australia (Community » Non Profit Organizations) * Low Flow Allocation Agreement (Governmental » State &… …   Abbreviations dictionary

  • Sonar — This article is about underwater sound propagation. For atmospheric sounding, see SODAR. For other uses, see Sonar (disambiguation) …   Wikipedia

  • Крылов, Виктор Владимирович — Виктор Владимирович Крылов Prof. Victor Krylov Дата рожден …   Википедия

  • Marine mammals and sonar — A Humpback whale Active sonar, the transmission equipment used on some ships to assist with navigation, has been suggested[1] to be detrimental to the health and livelihood of some marine animals, although the precise mechanisms for this are not… …   Wikipedia

  • Loudspeaker — For other uses, see Loudspeaker (disambiguation). An inexpensive, low fidelity 3½ inch speaker, typically found in small radios …   Wikipedia