Introduction to Sonar
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Winds, Waves, and Bubbles at the Air-Sea Boundary
JEFFREY L. HANSON WINDS, WAVES, AND BUBBLES AT THE AIR-SEA BOUNDARY Subsurface bubbles are now recognized as a dominant acoustic scattering and reverberation mechanism in the upper ocean. A better understanding of the complex mechanisms responsible for subsurface bubbles should lead to an improved prediction capability for underwater sonar. The Applied Physics Laboratory recently conducted a unique experiment to investigate which air-sea descriptors are most important for subsurface bubbles and acoustic scatter. Initial analyses indicate that wind-history variables provide better predictors of subsurface bubble-cloud development than do wave-breaking estimates. The results suggest that a close coupling exists between the wind field and the upper-ocean mixing processes, such as Langmuir circulation, that distribute and organize the bubble populations. INTRODUCTION A multiyear series of experiments, conducted under the that, in the Gulf of Alaska wintertime environment, the auspices of the Navy-sponsored acoustic program, Crit amount of wave-breaking activity may not be an ideal ical Sea Test (CST), I has been under way since 1986 with indicator of deep bubble-cloud formation. Instead, the the charter to investigate environmental, scientific, and penetration of bubbles is more closely tied to short-term technical issues related to the performance of low-fre wind fluctuations, suggesting a close coupling between quency (100-1000 Hz) active acoustics. One key aspect the wind field and upper-ocean mixing processes that of CST is the investigation of acoustic backscatter and distribute and organize the bubble populations within the reverberation from upper-ocean features such as surface mixed layer. waves and bubble clouds. -
Wetsuits Raises the Bar Once Again, in Both Design and Technological Advances
Orca evokes the instinct and prowess of the powerful ruler of the seas. Like the Orca whale, our designs have always been organic, streamlined and in tune with nature. Our latest 2016 collection of wetsuits raises the bar once again, in both design and technological advances. With never before seen 0.88Free technology used on the Alpha, and the ultimate swim assistance WETSUITS provided by the Predator, to a more gender specific 3.8 to suit male and female needs, down to the latest evolution of the ever popular S-series entry-level wetsuit, Orca once again has something to suit every triathlete’s needs when it comes to the swim. 10 11 TRIATHLON Orca know triathletes and we’ve been helping them to conquer the WETSUITS seven seas now for more than twenty years.Our latest collection of wetsuits reflects this legacy of knowledge and offers something for RANGE every level and style of swimmer. Whether you’re a good swimmer looking for ultimate flexibility, a struggling swimmer who needs all the buoyancy they can get, or a weekend warrior just starting out, Orca has you covered. OPENWATER Swimming in the openwater is something that has always drawn those types of swimmers that find that the largest pool is too small for them. However open water swimming is not without it’s own challenges and Orca’s Openwater collection is designed to offer visibility, and so security, to those who want to take on this sport. 016 SWIMRUN The SwimRun endurance race is a growing sport and the wetsuit requirements for these competitors are unique. -
The 10Th EAA International Symposium on Hydroacoustics Jastrzębia Góra, Poland, May 17 – 20, 2016
ARCHIVES OF ACOUSTICS Copyright c 2016 by PAN – IPPT Vol. 41, No. 2, pp. 355–373 (2016) DOI: 10.1515/aoa-2016-0038 The 10th EAA International Symposium on Hydroacoustics Jastrzębia Góra, Poland, May 17 – 20, 2016 The 10th EAA International Symposium on Hy- Dr. Christopher Jenkins: Backscatter from In- droacoustics, which is also the 33rd Symposium on • tensely Biological Seabeds – Benthos Simulation Hydroacoustics in memory of Prof. Leif Børnø orga- Approaches; nized in Poland, will take place from May 17 to 20, Prof. Eugeniusz Kozaczka: Technical Support for 2016, in Jastrzębia Góra. It will be a forum for re- • National Border Protection on Vistula Lagoon and searchers, who are developing hydroacoustics and re- Vistula Spit; lated issues. The Symposium is organized by the Prof. Andrzej Nowicki et al.: Estimation of Ra- Gdańsk University of Technology and the Polish Naval • dial Artery Reactive Response using 20 MHz Ul- Academy. trasound; The Scientific Committee comprises of the world – Prof. Jerzy Wiciak: Advances in Structural Noise class experts in this field, coming from, among others, • Germany, UK, USA, Taiwan, Norway, Greece, Russia, Reduction in Fluid. Turkey and Poland. The chairman of Scientific Com- All accepted papers will be published in the periodical mittee is Prof. Eugeniusz Kozaczka, who is the Pres- “Hydroacoustics”. ident of Committee on Acoustics Polish Academy of Sciences and Chairman of Technical Committee Hy- droacoustics of European Acoustics Association. Abstracts The Symposium will include invited lectures, struc- -
Acoustic Seabed and Target Classification Using Fractional
University of New Orleans ScholarWorks@UNO University of New Orleans Theses and Dissertations Dissertations and Theses 12-15-2006 Acoustic Seabed and Target Classification using rF actional Fourier Transform and Time-Frequency Transform Techniques Madalina Barbu University of New Orleans Follow this and additional works at: https://scholarworks.uno.edu/td Recommended Citation Barbu, Madalina, "Acoustic Seabed and Target Classification using rF actional Fourier Transform and Time-Frequency Transform Techniques" (2006). University of New Orleans Theses and Dissertations. 480. https://scholarworks.uno.edu/td/480 This Dissertation is protected by copyright and/or related rights. It has been brought to you by ScholarWorks@UNO with permission from the rights-holder(s). You are free to use this Dissertation in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Dissertation has been accepted for inclusion in University of New Orleans Theses and Dissertations by an authorized administrator of ScholarWorks@UNO. For more information, please contact [email protected]. Acoustic Seabed and Target Classication using Fractional Fourier Transform and Time-Frequency Transform Techniques A Dissertation Submitted to the Graduate Faculty of the University of New Orleans in partial fulllment of the requirements for the degree of Doctor of Philosophy in Engineering and Applied Sciences by Madalina Barbu B.S./MS, Physics, University of Bucharest, Romania, 1993 MS, Electrical Engineering, University of New Orleans, 2001 December, 2006 c 2006, Madalina Barbu ii To my family iii Acknowledgments I would like to express my appreciation to Dr. -
Fusion System Components
A Step Change in Military Autonomous Technology Introduction Commercial vs Military AUV operations Typical Military Operation (Man-Portable Class) Fusion System Components User Interface (HMI) Modes of Operation Typical Commercial vs Military AUV (UUV) operations (generalisation) Military Commercial • Intelligence gathering, area survey, reconnaissance, battlespace preparation • Long distance eg pipeline routes, pipeline surveys • Mine countermeasures (MCM), ASW, threat / UXO location and identification • Large areas eg seabed surveys / bathy • Less data, desire for in-mission target recognition and mission adjustment • Large amount of data collected for post-mission analysis • Desire for “hover” ability but often use COTS AUV or adaptations for specific • Predominantly torpedo shaped, require motion to manoeuvre tasks, including hull inspection, payload deployment, sacrificial vehicle • Errors or delays cost money • Errors or delays increase risk • Typical categories: man-portable, lightweight, heavy weight & large vehicle Image courtesy of Subsea Engineering Associates Typical Current Military Operation (Man-Portable Class) Assets Equipment Cost • Survey areas of interest using AUV & identify targets of interest: AUV & Operating Team USD 250k to USD millions • Deploy ROV to perform detailed survey of identified targets: ROV & Operating Team USD 200k to USD 450k • Deploy divers to deal with targets: Dive Team with Nav Aids & USD 25k – USD 100ks Diver Propulsion --------------------------------------------------------------------------------- -
Low-Frequency Active Towed Sonar
LOW-FREQUENCY ACTIVE TOWED SONAR Full-feature, long-range, low-frequency active and passive variable depth sonar (VDS) The Low-Frequency Active Sonar (LFATS) system is used on ships to detect, track and engage all types of submarines. L3Harris specifically designed the system to perform at a lower operating frequency against modern diesel-electric submarine threats. FEATURES > Compact size - LFATS is a small, > Full 360° coverage - a dual parallel array lightweight, air-transportable, ruggedized configuration and advanced signal system processing achieve instantaneous, > Specifically designed for easy unambiguous left/right target installation on small vessels. discrimination. > Configurable - LFATS can operate in a > Space-saving transmitter tow-body stand-alone configuration or be easily configuration - innovative technology integrated into the ship’s combat system. achieves omnidirectional, large aperture acoustic performance in a compact, > Tactical bistatic and multistatic capability sleek tow-body assembly. - a robust infrastructure permits interoperability with the HELRAS > Reverberation suppression - the unique helicopter dipping sonar and all key transmitter design enables forward, aft, sonobuoys. port and starboard directional LFATS has been successfully deployed on transmission. This capability diverts ships as small as 100 tons. > Highly maneuverable - own-ship noise energy concentration away from reduction processing algorithms, coupled shorelines and landmasses, minimizing with compact twin-line receivers, enable reverb and optimizing target detection. short-scope towing for efficient maneuvering, fast deployment and > Sonar performance prediction - a unencumbered operation in shallow key ingredient to mission planning, water. LFATS computes and displays system detection capability based on modeled > Compact Winch and Handling System or measured environmental data. - an ultrastable structure assures safe, reliable operation in heavy seas and permits manual or console-controlled deployment, retrieval and depth- keeping. -
Sonar for Environmental Monitoring of Marine Renewable Energy Technologies
Sonar for environmental monitoring of marine renewable energy technologies FRANCISCO GEMO ALBINO FRANCISCO UURIE 350-16L ISSN 0349-8352 Division of Electricity Department of Engineering Sciences Licentiate Thesis Uppsala, 2016 Abstract Human exploration of the world oceans is ever increasing as conventional in- dustries grow and new industries emerge. A new emerging and fast-growing industry is the marine renewable energy. The last decades have been charac- terized by an accentuated development rate of technologies that can convert the energy contained in stream flows, waves, wind and tides. This growth ben- efits from the fact that society has become notably aware of the well-being of the environment we all live in. This brings a human desire to implement tech- nologies which cope better with the natural environment. Yet, this environ- mental awareness may also pose difficulties in approving new renewable en- ergy projects such as offshore wind, wave and tidal energy farms. Lessons that have been learned is that lack of consistent environmental data can become an impasse when consenting permits for testing and deployments marine renew- able energy technologies. An example is the European Union in which a ma- jority of the member states requires rigorous environmental monitoring pro- grams to be in place when marine renewable energy technologies are commis- sioned and decommissioned. To satisfy such high demands and to simultane- ously boost the marine renewable sector, long-term environmental monitoring framework that gathers multi-variable data are needed to keep providing data to technology developers, operators as well as to the general public. Technol- ogies based on active acoustics might be the most advanced tools to monitor the subsea environment around marine manmade structures especially in murky and deep waters where divining and conventional technologies are both costly and risky. -
Doppler Sonar Current Indicator 8
DOPPLER SONAR CURRENT INDICATOR 8 Model High-performance current indicator displays accurate speed and current data at five depth layers on a 10.4" color TFT or virtually any VGA monitor utilizing a Black Box system www.furuno.com Obtain highly accurate water current measurements using FURUNO’s reliable acoustic technology. The FURUNO CI-68 is a Doppler Sonar Current The absolute movements of tide Indicator designed for various types of fish and measuring layers are displayed in colors. hydrographic survey vessels. The CI-68 displays tide speed and direction at five depth layers and ship’s speed on a high defi- nition 10.4” color LCD. Using this information, you can predict net shape and plan when to throw your net. Tide vector for Layer 1 The CI-68 has a triple-beam emission system for providing highly accurate current measurement. This system greatly reduces the effects of the Tide vector for Layer 2 rolling, pitching and heaving motions, providing a continuous display of tide information. When ground (bottom) reference is not available Tide vector for Layer 3 acoustically in deep water, the CI-68 can provide true tide current information by receiving position and speed data from a GPS navigator and head- ing data from the satellite (GPS) compass SC- 50/110 or gyrocompass. In addition, navigation Tide vector for Layer 4 information, including position, course and ship ’s track, can also be displayed The CI-68 consists of a display unit, processor Tide vector for Layer 5 unit and transducer. The control unit and display unit can be installed separately for flexible instal- lation. -
Transducers Recommended by Garmin
TRANSDUCER SELECTION 2021 GUIDE CHOOSING THE RIGHT TRANSDUCER PANOPTIX LIVESCOPE™ There are several types of sonar available, each with special capabilities. And each requires a different transducer to work most effectively. For optimum performance, it is very important to match the transducer to your device’s sonar. To start, make sure the transducer you are buying pairs with your unit, and determine what type of sonar technology you would like to add. Read through each section to learn more about the sonar technologies and transducers recommended by Garmin. Our award-winning Panoptix LiveScope sonar brings real-time scanning sonar to life. It shows highly detailed, easy-to-interpret live scanning sonar images of structure, bait and fish swimming below and around your boat in real time, even when your boat SONAR TECHNOLOGY // PAGE 3 ADDITIONAL TRANSDUCERS // PAGE 24 is stationary. • Panoptix Livescope™ • Transom Mount Full capabilities are available with the Panoptix LiveScope • Panoptix Livescope™ Perspective • Thru-hull Traditional System (see below). The Panoptix LiveScope™ LVS12 transducer ® Mode Mount provides an economical solution for your GPSMAP 8600xsv • Thru-hull CHIRP Traditional chartplotter — without the need for a black box -- with 30-degree • Panoptix™ All-seeing Sonar • In-hull 2018 forward and 30-degree down real-time scanning sonar views. • Scanning Sonar System: UHD • Pocket Mount Part no: 010-02143-00 LVS12 • Scanning Sonar System: CHIRP Sonar THREE MODES IN ONE TRANSDUCER ACCESSORIES AND SENSORS // PAGE 32 THE RIGHT MOUNTING // PAGE 10 PANOPTIX LIVESCOPE™ DOWN • Accessories • In-hull Mount • Smart Sensors • Kayak In-hull • NMEA 2000® • Trolling Motor Mount • Transom Mount • Thru-hull Mount Live, easy-to-interpret scanning sonar images of structure and swimming fish in incredible detail below your Panoptix LiveScope LVS12 Down GARMIN TRANSDUCERS // PAGE 12 boat — up to 200’. -
Matteo Bernasconi Phd Thesis
THE USE OF ACTIVE SONAR TO STUDY CETACEANS Matteo Bernasconi A Thesis Submitted for the Degree of PhD at the University of St Andrews 2012 Full metadata for this item is available in Research@StAndrews:FullText at: http://research-repository.st-andrews.ac.uk/ Please use this identifier to cite or link to this item: http://hdl.handle.net/10023/2580 This item is protected by original copyright This item is licensed under a Creative Commons Licence The use of active sonar to study cetaceans Matteo Bernasconi Submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy University of St Andrews July 2011 The use of active sonar to study cetaceans Matteo Bernasconi TABLE OF CONTENTS DECLARATIONS V ACKNOWLEDGMENTS VII ABSTRACT IX 1. INTRODUCTION 1 2. UNDERWATER ACTIVE ACOUSTIC 13 2.1 Historical notes 15 2.2 Sound: basic concepts 17 2.2.1 Sound propagation 18 2.2.2 Sound pressure and intensity 20 2.2.3 The decibel 21 2.2.4 Transmission Loss 22 2.2.5 Sound Speed 25 2.3 Transducers and beams 26 2.3.1 The beam pattern 28 2.3.2 The equivalent beam angle 29 2.3.3 Pulse and Ranging 30 2.4 Acoustic scattering 31 2.4.1 Target Strength 32 2.4.2 Target shape and orientation 33 2.4.3 Volume/area scattering coefficient 34 2.5 The sonar equation 35 3. CALIBRATION 39 3.1 The on‐axis sensitivity 41 3.2 Nearfield and Farfield 42 3.3 The TVG function 43 3.4 Standard experimental procedure 44 3.5 Calibration spheres 46 3.6 Calibration test of omnidirectional Sonar 47 3.6.1 Introduction 48 3.6.2 Method 49 3.6.3 Results & Discussion 51 3.6.4 Conclusion 57 4. -
A Review on Deep Learning-Based Approaches for Automatic Sonar Target Recognition
electronics Review A Review on Deep Learning-Based Approaches for Automatic Sonar Target Recognition Dhiraj Neupane and Jongwon Seok * Department of Information and Communication Engineering, Changwon National University, Changwon-si, Gyeongsangnam-do 51140, Korea; [email protected] * Correspondence: [email protected] Received: 13 October 2020; Accepted: 19 November 2020; Published: 22 November 2020 Abstract: Underwater acoustics has been implemented mostly in the field of sound navigation and ranging (SONAR) procedures for submarine communication, the examination of maritime assets and environment surveying, target and object recognition, and measurement and study of acoustic sources in the underwater atmosphere. With the rapid development in science and technology, the advancement in sonar systems has increased, resulting in a decrement in underwater casualties. The sonar signal processing and automatic target recognition using sonar signals or imagery is itself a challenging process. Meanwhile, highly advanced data-driven machine-learning and deep learning-based methods are being implemented for acquiring several types of information from underwater sound data. This paper reviews the recent sonar automatic target recognition, tracking, or detection works using deep learning algorithms. A thorough study of the available works is done, and the operating procedure, results, and other necessary details regarding the data acquisition process, the dataset used, and the information regarding hyper-parameters is presented in -
Implementation of Adaptive and Synthetic-Aperture Processing Schemes in Integrated Active–Passive Sonar Systems
Implementation of Adaptive and Synthetic-Aperture Processing Schemes in Integrated Active–Passive Sonar Systems STERGIOS STERGIOPOULOS, SENIOR MEMBER, IEEE Progress in the implementation of state-of-the-art signal- NOMENCLATURE processing schemes in sonar systems is limited mainly by the moderate advancements made in sonar computing architectures Complex conjugate transpose operator. and the lack of operational evaluation of the advanced processing Power spectral density of signal . schemes. Until recently, matrix-based processing techniques, such as adaptive and synthetic-aperture processing, could not AG Array gain. be efficiently implemented in the current type of sonar systems, Small positive number designed to main- even though it is widely believed that they have advantages that can address the requirements associated with the difficult tain stability in normalized least mean operational problems that next-generation sonars will have to square adaptive algorithm. solve. Interestingly, adaptive and synthetic-aperture techniques Narrow-band beam-power pattern of may be viewed by other disciplines as conventional schemes. For a line array expressed by the sonar technology discipline, however, they are considered as advanced schemes because of the very limited progress that has . been made in their implementation in sonar systems. Broad-band beam-power pattern of a line This paper is intended to address issues of implementation of array steered at direction . advanced processing schemes in sonar systems and also to serve as a brief overview to the principles and applications of advanced Beams for conventional or adaptive sonar signal processing. The main development reported in beam formers or plane wave this paper deals with the definition of a generic beam-forming response of a line array steered structure that allows the implementation of nonconventional at direction and expressed by signal-processing techniques in integrated active–passive sonar .