Sonar Technology Research Articles

Gentle Giants in Dark Waters: Using Side-Scan Sonar for Manatee Research

Abstract: Manatees are tropical marine mammals that live in a wide variety of aquatic habitats ranging from coastal marine areas to freshwater lakes and rivers located hundreds of kilometers inland. All manatee species are currently characterized as Vulnerable by the International Union for Conservation of Nature (IUCN), primarily due to anthropogenic causes (i.e. poaching, habitat destruction, pollution, collisions with boats) and all of the environments they live in present challenges to biologists and wildlife managers. Tropical freshwater systems are especially difficult to work in because they are generally tannin-stained or turbid and water clarity is very restricted. Locating manatees and observing their behavior in these environments is extremely difficult and is a major limiting factor in determining population parameters. We summarize the use of sonar technology as an aid to detect and study manatees in these freshwater systems. First, by a summary of what has been attempted before our efforts, followed by presenting the various ways we have used this technology in the past 6 years to 1) detect manatees, 2) characterize manatee habitat in ways that would not be possible otherwise, 3) identify mother-calf pairs, and 4) assist in manatee captures. Finally, we discuss the advantages and limitations of using this technology for manatee conservation and research and present directions in which we believe future work can be directed, such as the determination of manatee abundance via distance sampling surveys using side-scan sonar and the use of one of the latest developments in acoustic technology, dual-frequency identification sonar.

Sonar surveying of caverns and 3D modelling of entire cavern fields

The echometric surveillance of caverns is especially important with regards to their safe and effective operation. As opposed to brine production caverns, storage caverns are generally subject only to convergence and they do not undergo large and irregular changes of shape under normal conditions. Echometric surveillance is therefore primarily employed to obtain proof of the cavern stability and convergence. Applying the state-of-the-art sonar technology it is possible during an echometric survey to measure and process the geometry of relevant parameters such as speed of sound, pressure and temperature with a single tool run. Today, specialized software allows us to present all the cavern field data in a common computer model, starting from the sonar survey results over the surface situation, and the well courses until the geology. In the first instance of the presentation the techniques used for surveying caverns as well as the survey procedure are described in general. Subsequently some interesting results of individual sonar surveys are presented. In the paper it is shown by means of a practical example what benefits cavern operators can derive from 3D-models of cavern field sites. Besides being useful for presentation purposes, such models can among other things help in the correlation of the survey results with the geology and support planning. Modeling is done with the CavWalk Professional software, which has been specially developed for the presentation of cavern fields. The software allows the user to undertake virtual excursions through the 3D-model at the surface as well as underground. In the spatial representation of one or several caverns the observer can move around outside and inside the caverns.

Ambiguity function based on the linear canonical transform

The ambiguity function (AF) as an important tool for time-frequency analysis, has widely been used in radar signal processing, sonar technology and so on. It does well in analysing chirp signals. However, it fails in estimating the cubic phase (CP) signal, which is required in many applications. As the generalisation of the Fourier transform (FT), the linear canonical transform (LCT) has received much attention, and has found many applications in filter design, pattern recognition, optics and so on. In this study, the authors define a new kind of AF - the AF based on the LCT (LCTAF), which is proposed to estimate the CP signal. Some important properties of LCTAF are discussed, such as symmetry and conjugation property, shifting property and Moyal formula. The relationships between the LCTAF and other time-frequency analysis distributions are derived, including the classical AF, the Wigner distribution function (WDF) based on LCT, the short-FT and the wavelet transform. The linear canonical AF (LCAF) is another kind of AF. The authors also discuss its relation with AF and WDF and give some new properties of the LCAF. At last, the LCTAF is applied for estimating the CP signal. The simulation indicates that the LCTAF is useful and effective.

Research on the Technology of Three-Dimensional Surface Topological Reconstruction of Underground Rock Salt Cavern Based on Sonar Detection Data

After analyzing the characteristics of rock salt and the feasibility and importance of using underground rock salt cavern as energy stockpiles, this paper explains in detail about the principle of sonar detection technology in cavern measuring and its data organization. This paper studies the technology of three-dimensional surface topological reconstruction of underground rock salt cavern based on sonar detection data with half-edge data structure and boundary representation models. Meanwhile, by conducting validity check for constructed surface model and repair of possible defects, the paper finds correct and effective three-dimensional surface models of underground rock salt cavern, and provides effective data base for the stability analysis, creep analysis and other numerical simulations of underground rock salt cavern. This method, with important economic and social significance, can provide a scientific basis and technological support for the construction of caverns, especially for the safe and rational use of underground rock salt cavern.

Multibeam Sonar Technology and Geology to Interpret Ancient Harbor Subsidence off Crotone Peninsula, Italy

La technologie du sonar multifaisceaux a été développée pour examiner en détail les fonds marins. Cette méthode offre une précision excellente de quelques centimètres et couvre des surfaces de plusieurs centaines mètres carrés. Dans notre étude, ces images sont utilisées à des fins géoarchéologiques en relation avec le contexte géologique. L’exemple présenté correspond à la marge ionienne de la Calabre, la zone de Capo Colonna‑Punta Scifo située au large de la péninsule de Crotone. Nous montrons comment le sonar multifaisceaux peut aider à résoudre des problèmes d’identification et d’affaissement du fond marin jusqu’à une profondeur de 13 m au‑dessous du niveau actuel de la mer. Ces images, couplées avec les observations des plongeurs, indiquent des structures d’origine humaine qui peuvent correspondre à une installation portuaire grecque maintenant submergée. Ces structures sont positionnées sur un fond marin qui s’est affaissé d’environ 10 m depuis la fin de l’antiquité. Cette immersion traduit un certain nombre de pulsations tectoniques en relation avec l’arc de Calabre.

Synthetic Aperture Imaging of Surface Laid Targets by Sound

This paper discusses the design and implementation of a synthetic aperture acoustic imaging system for investigating solid objects in an outdoor environment. Measurement results are reported for a setup consisting of a rail-mounted transceiver, digital data acquisition and control system, and local storage with data post processing capabilities. This imaging system works much like typical sonar and RF synthetic aperture radar technologies but operates above ground and uses acoustic waves in air for its interrogation.

Exploratory and Instantaneous Swimming Speeds of Amphidromous Fish School in Shallow-Water Coastal Lagoon Channels

Fish school swimming speeds is essential for ecological and management studies. The multibeam sonar in horizontal beaming provided dynamic echo traces of mobile fish schools. We used two school swimming speed indicators: the average of a series of instantaneous speed values, and the exploratory speed. These swimming speeds were estimated for each fish school observed on the basis of their Euclidian position within the sonar beams. The average ISS values per school ranged from 0.15 m s−1 to 4.46 m s−1, while the ESS values per school were lower, ranging from 0.04 m s−1 to 3.77 m s−1. Multibeam sonar technology makes it possible to measure fish school swimming speeds in their natural habitat at small spatio-temporal scales. This methodology can therefore be used to analyse in situ their movements, and has a wide range of applications in behavioural studies and management purposes.

Extended Fourier for multi-component chirp analysis: Application to bat signals.

Much progress has been made recently for improving the time-frequency analysis. Typically, signals have frequencies that change with time. Even, in bio-acoustic, creatures such as bats and dolphins rely on time varying signals for echolocation and target detection. With the advent of pulse compression techniques in radar and sonar technologies, the need for time-frequency representations has become more important. The underlying basis of many of the techniques is the Fourier transform. In this paper, we present a technique, which relies on Fourier transform, exhibiting both greater resolution and conceptual simplicity. We have termed the technique Fourier extension analysis since it extends the use of Fourier analysis to signals with time varying components. Furthermore, we demonstrate how the analysis extends naturally to a time-frequency representation using the image processing Hough transform tool without the need for windowing, as it is the case for short time Fourier transform, for example, and we also discuss how the resolutions are obtainable with regard to separation of multi-component chirp signals. Examples will be presented for the analysis of some bat signals showing the capabilities of the developed technique compared to other methods in terms of resolution and cross term free advantages.

ソナー技術と気泡運動

ソナー技術と気泡運動

A Study on Fusion and Visualization using Multibeam Sonar Data with Various Spatial Data Sets for Marine GIS

According to the remarkable advances in sonar technology, positioning capabilities and computer processing power we can accurately image and explore the seafloor in hydrography. Especially, Multibeam Echo Sounder can provide nearly perfect coverage of the seafloor with high resolution. Since the mid-1990's, Multibeam Echo Sounders have been used for hydrographic surveying in Korea. In this study, new marine data set as an effective decision-making tool in various fields was proposed by visualizing and combining with Multibeam sonar data and marine spatial data sets such as satellite image and digital nautical chart. The proposed method was tested around the port of PyeongTaek-DangJin in the west coast of Korea. The Visualization and fusion methods are described with various marine data sets with processing. We demonstrated that new data set in marine GIS is useful in safe navigation and port management as an efficient decision-making tool.

Nanorobots, NEMS, Nanoassembly, Control and Sensors

Nanorobotics encompasses the design, fabrication and programming of robots with overall dimensions below a few micrometers, and the programmable assembly of nonsocial objects. Nanorobots are quintessential nanoelectromechanical systems (NEMS) and raise all the important issues that must be addressed in NEMS design: sensing, actuation, control, communications, power, and interfacing across spatial scales and between the organic/inorganic and biotic/abiotic realms. In this paper presentation I have tried to use the idea of nanorobots to design an own autonomous robot that can be used for medical and mechanical purposes and hence can be used in any field. This paper discusses the various calculations involved in making the rebot and its neseccary design in making the sensor too. Nanorobots are expected to have revolutionary applications in such areas as environmental monitoring and health care. This paper begins by discussing nanorobot construction, which is still at an embryonic stage. The emphasis is on nanomachines, an area which has seen a spate of rapid progress over the last few years. Nanoactuators will be essential components of future NEMS. The paper’s focus then changes to nanoassembly by manipulation with scanning probe microscopes (SPMs), which is a relatively well established process for prototyping nanosystems. Prototyping of nanodevices and systems is important for design validation, parameter optimization and sensitivity studies. Nanomanipulation also has applications in repair and modification of nanostructures built by other means. High throughput SPM manipulation may be achieved by using multitip arrays. Experimental results are presented which show that interactive SPM manipulation can be used to accurately and reliably position molecular-sized components. These can then be linked by chemical or physical means to form subassemblies, which in turn can be further manipulated. Applications in building wires, single-electron transistors and nanowaveguides are presented. This presentation will also discuss the use of ultrasonic sensorswhich can act as a transducer i.e can act as the receiver and transmitter device as well as controlling the device as per the necessary pin configuration given below, which when connected with an atmel micro-controller can do a lot of stuff simultaneously like detecting, ranging, sensing, manipulating with the help of mathematical modeling, etc. this could possibly replace the sonar technology and also could prove of a big use in medicine. The only disadvantage being the cost worthy of it. But then it is going to be our proposal for the technology that could be the next ‘small’ to replace the ‘big’. Using this concept I have made an autonomous bot that has specially designed control and ultrasonic sensors all of them working on the principle of nanoelectronic devices. To give as an experimental proof I have sent a video of its working and even the sensor pin configuration and the coding part can be easily explained if given an opportunity to explain( we have to use simple c++ language to code it to haxa notation) Also the use of biomotors would take care of the renew ability of the product and hence it is very user-friendly. Basically it’s a proposal and working encompassing most of the process. The full text of the article is not available in the cache. Kindly refer the IJCA digital library at www.ijcaonline.org for the complete article. In case, you face problems while downloading the full-text, please send a mail to editor at editor@ijcaonline.org

A Cost Effective Method to Enhance Dredge Mine Reconciliation in Heavy Minerals Mining Industry

Heavy mineral deposits of placer origin are mostly found as beach or dune deposits. Suction cutter or bucket-wheel dredgers are used to exploit such deposits when water is present for the maintenance of artificial channels and dredge ponds. Production reconciliation of dredge mining is a complex process because slumping of material causes mixing of material to take place amongst resource blocks during mining operations. This paper reviews the applicability of sonar technology for the determination of material losses taking place in the dredge ponds, and also reviews the applicability of radio frequency identification (RFID) tags in conjunction with sonar technology as a cost effective method to enhance dredge mine production reconciliation in the heavy minerals mining industry.

Processing techniques applied to underwater target echoes and their relationships.

Interest in acoustic scattering from underwater unexploded ordnance (UXO) has been increasing because of the growing need for sonar technology able to detect submerged UXO and to efficiently separate these detections from those due to natural and man-made clutter. Recent efforts range from laboratory and numerical studies seeking to understand the basic structural acoustic echo formation processes and the environmental effects on them to field exercises determining how well a particular detection/identification technology performs. This paper discusses several important scattering-based constructs, which have been utilized in both the basic UXO studies and the technology exercises as well. They include: (1) σ(ω, θ), the frequency/angle-dependent scattering cross section; (2) standard imagery, oftentimes implemented with synthetic aperture arrays; (3) reflection tomography imaging; and (4) supersonic imaging using holographic techniques. Without a clear appreciation for the differences among the constructs, it is difficult to properly relate the results of the various studies. We have measured the broadband scattering from several underwater UXO targets using laboratory, rail-based, and AUV systems and processed the data using the above constructs. The use of a common, high quality UXO scattering data base in this process helps clarify the differences and relationships among the constructs. [Work supported by SERDP and ONR.]

Marine ecosystem acoustics: contributions of sonar technology

Sonar is considered in the widest sense as an acoustic system consisting of a transmitter and receiver of underwater sound. It may be monostatic, bistatic, or multi‐static; narrowband or broadband; with one or more fixed, rotating, or electronically formed beams. Transducers may be mounted on hulls of vessels and autonomous underwater vehicles, fixed structures, or seafloor; towed; or suspended. Spatial scales may be sampled from millimeters to thousands of kilometers; corresponding temporal scales vary from a fraction of a second, as in target‐tracking, to seasons, as in observing animal migration. Several sonar types are described. Contributions of sonar technology to ecosystem studies, both actual and potential, are noted. These include, for example, fine‐scale surveying of pelagic and semi‐demersal fish by scientific echo sounder; mapping of the three‐dimensional structure of fish aggregations and bathymetry by multibeam sonar; quantification of benthic egg beds of the squid Loligo opalescens by sidescan sonar; and large‐scale surveying of swimbladdered fish by parametric sonar. Each of these sonar systems has potential for detection, quantification, and classification of marine organisms, as well as for characterization of the habitat, hence yielding the kind of information that is required for ecosystem assessment and management.

Mikrochirurgische Entfernung tiefliegender Gefäßmißbildungen mit Hilfe der Sonar-Stereometrie

The advantages of a new, dynamic sonar technology in open stereotactic microsurgery are demonstrated by means of three surgical procedures for deep-seated vascular malformations that are not easy of access. With this method, targets can be aimed at without using rigid, obstructive pointing devices as in conventional stereotaxy. On the contrary, it is possible to take advantage of preformed anatomical spaces reaching the lesion most carefully by means of light-weight, free-hand on-target instruments. The spatial information, correlated with a CT data set, is displayed in real time with an accuracy of +/- 1 mm. Additional image data from MR and digital angiography can be used interactively.

Marine Mammals Still Imperiled After Sonar Ruling

ENVIRONMENTA federal judge imposed significant restrictions last week on use of the U.S. Navy's submarine-chasing sonar technology in training exercises taking place off the southern California coast through January 2009.

Advances in upward looking sonar technology for studying the processes of change in Arctic Ocean ice climate

A major impetus for scientific studies of climate change in the Arctic Ocean has beenthe reduction in the areal extent and thickness of its sea ice cover. An extendedmeasurement record of the horizontal dimensions of this ice cover is available for thefull Arctic Ocean Basin based upon a record compiled from more than 30 years ofrelatively continuous satellite based measurements. Unfortunately, data accumulationsfor the ice cover’s vertical dimension, ie, sea ice thickness, tend to be limited to data setswith durations no longer than 15 years, reflecting underlying greater measurementdifficulties. Moreover, the longest duration ice thickness data collection efforts have beenconfined only to two specific portions of the Basin, namely, Fram Strait and the Canadiansector of the Beaufort Sea. Elsewhere, the available data sets are either of notablyshorter duration or non-existent.Upward-looking sonar (ULS) has been and continues to be the primary source ofdata with volumes and accuracy sufficient for meaningfully monitoring ice thickness.Originally deployed from polar-traversing submarines during the Cold War, the limitedamounts and accessibility of the collected data stimulated development of purpose-builtsea-floor moored ULS instrumentation which, beginning in the late 1980s, began tosupply the bulk of newly acquired ice draft and ice under-surface topography data.Technological advances have subsequently led to new generations of ULS instrumentsincluding ice-profiling sonar (IPS), incorporating much expanded on-board data storagecapacities (69 Mbytes to 8 Gbytes) and powerful real-time firmware which now allowunprecedented temporal (ping rates of up to 1Hz) and horizontal resolution of icetopography. These instruments operate autonomously during one year or longer deployments,returning draft data on time and spatial scales of 1s and 1m or better, respectively,which are essential to understandings of mechanical and thermodynamical aspectsof sea ice processes. Such processes govern ocean-atmosphere exchanges in polarwaters, thereby determining ice extent and thickness parameters. The larger data storage capacities of the newest instruments also allow collection of additional informationassociated with acoustic returns from different levels in the upper water column and thelower ice cover. Such data have potential for improving understandings of ice processesoccurring during the initial freeze-up and early consolidation phases of sea ice growth onthe basis of acoustic backscatter from frazil, grease, shuga and nilas ice forms. WithInternational Polar Year programmes now well underway, ice profiling instruments,sharing a common technology, are and/or will be deployed in unprecedented numbersfrom both fixed subsurface moorings and drifting buoys. This deployment commitmentholds great promise for delivery of data with both temporal and spatial detail and arealcoverage sufficient to strongly upgrade present capabilities for monitoring and modellingice cover change.

Assessment of lake sturgeon spawning stocks using fixed-location, split-beam sonar technology

Summary Fixed-location, split-beam sonar technology was used successfully to identify adult lake sturgeon Acipenser fulvescens as they moved upstream and downstream for spawning in the Sturgeon River, Michigan, May–June 2004. A Hydroacoustic Technology Inc. Model 241 Split-Beam Echo Sounder operating at 200 kHz and a single 4 × 10° elliptical-beam transducer with a near field range of 1.7 m set perpendicular to the river flow was used. Data collected from migrating lake sturgeon included direction of movement, swimming speed, range from transducer, time and date of passage, and target strength. The spawning population of lake sturgeon was estimated to be at 350–400 fish, with almost equal numbers of fish seen moving upstream as downstream. Most fish were recorded moving within the mid-section of the river, 1.5–1.65 m deep, and swimming speeds upstream were slower than those for downstream moving fish. These results show that spilt-beam sonar can be applied to lake sturgeon assessments, without the stress of actually handling these large, pre-spawning fish.

Submeter bathymetric mapping of volcanic and hydrothermal features on the East Pacific Rise crest at 9°50′N

Recent advances in underwater vehicle navigation and sonar technology now permit detailed mapping of complex seafloor bathymetry found at mid‐ocean ridge crests. Imagenex 881 (675 kHz) scanning sonar data collected during low‐altitude (∼5 m) surveys conducted with DSV Alvin were used to produce submeter resolution bathymetric maps of five hydrothermal vent areas at the East Pacific Rise (EPR) Ridge2000 Integrated Study Site (9°50′N, “bull's‐eye”). Data were collected during 29 dives in 2004 and 2005 and were merged through a grid rectification technique to create high‐resolution (0.5 m grid) composite maps. These are the first submeter bathymetric maps generated with a scanning sonar mounted on Alvin. The composite maps can be used to quantify the dimensions of meter‐scale volcanic and hydrothermal features within the EPR axial summit trough (AST) including hydrothermal vent structures, lava pillars, collapse areas, the trough walls, and primary volcanic fissures. Existing Autonomous Benthic Explorer (ABE) bathymetry data (675 kHz scanning sonar) collected at this site provide the broader geologic context necessary to interpret the meter‐scale features resolved in the composite maps. The grid rectification technique we employed can be used to optimize vehicle time by permitting the creation of high‐resolution bathymetry maps from data collected during multiple, coordinated, short‐duration surveys after primary dive objectives are met. This method can also be used to colocate future near‐bottom sonar data sets within the high‐resolution composite maps, enabling quantification of bathymetric changes associated with active volcanic, hydrothermal and tectonic processes.

3D seismic versus multibeam sonar seafloor surface renderings for geohazard assessment: Case examples from the central Scotian Slope

Detailed seafloor morphologic images can be rendered from the seafloor pick of 3D seismic data sets and from multibeam bathymetric sonar data. These data are frequently used in geohazard and environmental assessments to characterize the seafloor, interpret the geologic environment, and calculate parameters such as slope angle. In general, the accuracy and value of these quantitative assessments improve with higher resolution. In deepwater, the coverage of depth soundings by 3D seismic and multibeam sonar technologies are at a similar scale, yet the physical principles of operation of the two systems are distinctly different. The purpose of this study is to evaluate theoretical and practical aspects of the two data types, especially with respect to vertical and horizontal resolution and precision as they pertain to deepwater geohazard assessment.