Sonar Range Research Articles

Automatic Relevance Determination Kernel-Embedded Gaussian Process Regression for Sonar-Based Human Leg Localization with a Mobile Robot

Human leg localization problems involving sonar sensing can be posed as a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nonlinear regression problem</i> , and, nonparametric Bayesian methods, such as the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Gaussian process regression</i> (GPR) model, are potential solution candidates. In this work, to overcome the problem of irrelevant input features from the sonar range data, an advanced <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">automatic relevance determination</i> kernel structure is proposed to be used in the GPR model instead of the commonly used standard isotropic kernel. It is able to extract high-relevance input features even from partially trained data, thus offering a better generalization ability while improving the prediction rates and robustness significantly.

Abundance, survival, and annual rate of change of Cuvier's beaked whales (Ziphius cavirostris) on a Navy sonar range

AbstractBayesian mark‐recapture estimates of survival, abundance, and trend are reported for Cuvier's beaked whales (Ziphius cavirostris) using a Navy training range off southern California. The deep‐diving beaked whale family is exceptionally vulnerable to mid‐frequency active sonar (MFAS), which has been implicated in mass strandings and altered foraging behavior. Extremely low sighting probabilities impede studies of population‐level impacts of MFAS on beaked whales. The San Nicolas Basin hosts a Navy training range subject to frequent MFAS use and attracts high densities of Z. cavirostris. An 11‐year (2007–2018) photo‐identification program leveraged automated acoustic detection and location capabilities on the range's 1,800‐km2 hydrophone array to enhance capture probability. Estimated population parameters for Z. cavirostris using the range included mean (90% credibility intervals) apparent annual survival of 0.950 (0.899–0.986), annual number of individuals as 121 (71–219), and annual rate of change of −0.8% (−5.6%–4.1%). Simulations show the probability of detecting abundance changes is currently low, but can be greatly improved through continued monitoring and increased effort. Complementary data collection on habitat use and demographic rates in San Nicolas and surrounding basins is also essential to relating direct effects of MFAS use to changes in vital rates and broader population outcomes.

Investigating the resolution ability of the HC-SRO4 ultrasonic sensor

An Arduino microcontroller has been used for many projects since its first presentation in 2005. This integrated chip used with a variety of sensors to construct many attractive projects and circuits. In this paper, we aim to investigate the resolution ability of one of the famous sensors attached to the Arduino which is called the ultrasonic HC-SR04 sensor. This sensor basically, is made from a transmitter and receiver that work in the sonar range of frequencies. It is used to indicate the distance of objects similar to the Radar principle. By experimental results another feature could be added to the data sheet of this sensor, named as distance resolution. By applying a reasonable shape and dimension for the target objects at a distance of 11 cm, the experimental results show that this sensor has resolution ability configured in the range of 7 cm displacement between two adjacent objects. Furthermore, the paper suggests increasing the sensor aperture to increase such ability for certain application that used the sensor for discrimination between adjacent objects.

Counting and sizing Atlantic bluefin tuna schools using medium range sonars of baitboats in the Bay of Biscay

This study reports on the automated counting and sizing of Atlantic bluefin tuna (ABFT) schools using medium range sonar data extracted from a systematic acoustic sampling survey in the Bay of Biscay (BoB). An image analysis program is used to obtain the morphometric characteristics of any objects detected by the sonar. These objects are classified into “Tuna” or “Non-Tuna” using a morphometric classification model (MCM). Next, the vessel's operational data are also extracted using optical character recognition (OCR), and a novel methodology for counting and sizing ABFT schools is developed. Validation of the school counting methodology is carried out by comparing the number of observed and estimated schools, and the dimensions of the schools are standardised for the effect of sonar gain and range. Unlike existing baitboat catch per unit effort (CPUE)-based abundance indices, this methodology avoids bias that arises from inter-annual changes in food availability, stomach repletion and/or feeding behaviour. Thus, the estimated number of tuna schools and their relative size can provide more fisheries with independent abundance estimates. This methodology can be applied in two ways: i) for detecting schools on images recorded by the commercial baitboat fleet during their regular fishing operations, to replace the currently used CPUE index with a new standardised detection per unit effort (DPUE) index, or ii) for performing scientifically designed systematic acoustic surveys to monitor the abundance of this species in the BoB year after year.

Mixed Layer Budget Terms on Acoustic Propagation A Study based on the Butterfly Track Experiment in the South Eastern Arabian Sea

A butterfly type of repeat track cruise was carried out in the South Eastern Arabian Sea (off Minicoy) onboard INS Sagardhwani during July 2016 to Aug 2016. We have also made use of the data from OMNI buoy, AD09, which is about 6 km close to the centre station of butterfly track. Air sea flux, the horizontal current data from AD09 and the time series data collected from the butterfly experiment were analyzed to compute the mixed layer heat and salt budget. The short-term thermo-haline variability off Minicoy, relative contribution of heat/salt budget terms in MLD and its effects on acoustic propagation are addressed in this paper. In this study, we found that most dominating term in the mixed layer heat budget estimation is net surface heat flux followed by the advective terms. However the salinity in the mixed layer is dominated by the contribution of buoyancy mixing due to night time evaporative cooling. During the calm, sunny day, the so-called afternoon effect due to the diurnal heating restricts the sonar range. But during the windy day, the wind/wave mixing prevents the warming of the surface layer which in turn enhances the sonar range. Similarly, the night time cooling also enhance the acoustic propagation range. The presence of Arabian Sea High Salinity Watermass in the surface layer also enhances the acoustic propagation.

Multi-data sensor fusion framework to detect transparent object for the efficient mobile robot mapping

PurposeAn efficient perception of the complex environment is the foremost requirement in mobile robotics. At present, the utilization of glass as a glass wall and automated transparent door in the modern building has become a highlight feature for interior decoration, which has resulted in the wrong perception of the environment by various range sensors. The perception generated by multi-data sensor fusion (MDSF) of sonar and laser is fairly consistent to detect glass but is still affected by the issues such as sensor inaccuracies, sensor reliability, scan mismatching due to glass, sensor model, probabilistic approaches for sensor fusion, sensor registration, etc. The paper aims to discuss these issues.Design/methodology/approachThis paper presents a modified framework – Advanced Laser and Sonar Framework (ALSF) – to fuse the sensory information of a laser scanner and sonar to reduce the uncertainty caused by glass in an environment by selecting the optimal range information corresponding to a selected threshold value. In the proposed approach, the conventional sonar sensor model is also modified to reduce the wrong perception in sonar as an outcome of the diverse range measurement. The laser scan matching algorithm is also modified by taking out the small cluster of laser point (w.r.t. range information) to get efficient perception.FindingsThe probability of the occupied cells w.r.t. the modified sonar sensor model becomes consistent corresponding to diverse sonar range measurement. The scan matching technique is also modified to reduce the uncertainty caused by glass and high computational load for the efficient and fast pose estimation of the laser sensor/mobile robot to generate robust mapping. These stated modifications are linked with the proposed ALSF technique to reduce the uncertainty caused by glass, inconsistent probabilities and high load computation during the generation of occupancy grid mapping with MDSF. Various real-world experiments are performed with the implementation of the proposed approach on a mobile robot fitted with laser and sonar, and the obtained results are qualitatively and quantitatively compared with conventional approaches.Originality/valueThe proposed ASIF approach generates efficient perception of the complex environment contains glass and can be implemented for various robotics applications.

Route optimizing and following for autonomous underwater vehicle ladder surveys

An autonomous underwater vehicle is able to conduct coverage detections, such as sea terrain mapping and submerged objects detection, using sonar. This work addresses the task of both optimizing and following routes that present a ladder shape. First, a planning method to determine a nearly optimal coverage route is designed. The track spacing is optimized considering the seabed type and the sonar range for the purpose of increasing detection probability. It also adds adaptability to confined water, such as harbors, by decomposing the geometrically concave mission region during the processing of the environmental data. Next, a decoupled and two-layered structure is adopted to design the following controller. The route is followed in the form of sequenced-lines tracking. A proportion–integral–derivative algorithm with fuzzy parameters adjustment is employed to calculate a reference heading angle according to the transverse position deviation in designing the guidance controller. An adaptive nonlinear S-surface law is adopted to design the yaw control. The route following the method is demonstrated with sonar (including side scanning sonar and multi-beam echo sounder) imagery collected in terrain mapping and object detection through sea trials.

The Sonar Model for Humpback Whale Song Revised.

Why do humpback whales sing? This paper considers the hypothesis that humpback whales may use song for long range sonar. Given the vocal and social behavior of humpback whales, in several cases it is not apparent how they monitor the movements of distant whales or prey concentrations. Unless distant animals produce sounds, humpback whales are unlikely to be aware of their presence or actions. Some field observations are strongly suggestive of the use of song as sonar. Humpback whales sometimes stop singing and then rapidly approach distant whales in cases where sound production by those whales is not apparent, and singers sometimes alternately sing and swim while attempting to intercept another whale that is swimming evasively. In the evolutionary development of modern cetaceans, perceptual mechanisms have shifted from reliance on visual scanning to the active generation and monitoring of echoes. It is hypothesized that as the size and distance of relevant events increased, humpback whales developed adaptive specializations for long-distance echolocation. Differences between use of songs by humpback whales and use of sonar by other echolocating species are discussed, as are similarities between bat echolocation and singing by humpback whales. Singing humpback whales are known to emit sounds intense enough to generate echoes at long ranges, and to flexibly control the timing and qualities of produced sounds. The major problem for the hypothesis is the lack of recordings of echoes from other whales arriving at singers immediately before they initiate actions related to those whales. An earlier model of echoic processing by singing humpback whales is here revised to incorporate recent discoveries. According to the revised model, both direct echoes from targets and modulations in song-generated reverberation can provide singers with information that can help them make decisions about future actions related to mating, traveling, and foraging. The model identifies acoustic and structural features produced by singing humpback whales that may facilitate a singer’s ability to interpret changes in echoic scenes and suggests that interactive signal coordination by singing whales may help them to avoid mutual interference. Specific, testable predictions of the model are presented.

The Imaging of Gdansk Bay Seabed by Using Side Sonar

Abstract This paper is mainly aimed at presentation of an impact of environmental conditions on imaging accuracy by using hydro-acoustic systems in waters of a high non-uniformity of spatial distribution of hydrological parameters. Impact of refraction on erroneous estimation of range, in case of wave radiation into water under a large angle, like in side sonars or multi-beam echo-sounders, is especially important. In this paper seasonal changes in sound speed and its impact on acoustic beam refraction is discussed. And, examples which illustrate errors in determination of side sonar range occurred during last investigations carried out in Gdansk Bay waters are presented.

Designing of Low Cost Arduino Based Ultrasonic SONAR System

Sonar (Sound Navigation and Ranging) was covertly created by few countries during the reign of World War II. SONAR can be used to detect some moving object. It helps in the measurement of distance and angle from the observer. It works on the principle of Doppler shift. The designing of cheaper SONAR system for security purpose is the requirement of an industry. In this research Paper, the designing and implementation of Arduino based SONAR system using ultrasonic sensor are presented. The device is able to detect the object, calculate its distance (up to 30cm) and can determine the elevation angle. It provides a cheaper solution for security purposes.

A Smartphone Compatible SONAR Ranging Attachment for 2-D Mapping

The ability to attach external devices to smartphones has revolutionized the role of smartphones by extending their capabilities beyond the limitations of commodity hardware. Developing external attachments that allow smartphones to sense the depth of an area will facilitate the development of new immersive applications and technologies. In this paper, we propose a smartphone compatible SONAR ranging attachment and address the compatibility problem by proposing a hybrid hardware/software modulator that allows a digital sensor to communicate with a smartphone via the 3.5-mm headphone jack, found on most smartphones. We evaluate the proposed sensor using two metrics, accuracy and spatial resolution. We evaluate the accuracy of this system by measuring known distances with the sensor and comparing them. We measure the sensor’s spatial resolution by using ranging information from the SONAR module along with the phone’s gyroscope, accelerometer, and magnetometer to construct a two-dimensional map of a space.

Observations of in situ Atlantic bluefin tuna (Thunnus thynnus) with 500-kHz multibeam sonar

Abstract Field studies to investigate the survey capability of a 500-kHz multibeam sonar to monitor and quantify Atlantic bluefin tuna were undertaken at several fishing locations (commercial and recreational) off Prince Edward Island and at a grow-out pen in Nova Scotia. The results demonstrate that individual bluefin can be detected, enumerated, and tracked acoustically within the swathe of the sonar. Bluefin were observed individually, and in groups ranging from 2 to 16 fish. Schooling tuna, assumed to be foraging, were observed moving in a soldier formation. Estimates of in situ swimming speeds (0.5–11.0 m s−1) were made by tracking individual fish within the swathe. The mean interspatial distance between fish when swimming in a group of two or more tuna was estimated to be 8.94 m with a range of 2.68–22.63 m. Groups of up to 48 bluefin were observed aggregating around active herring gillnet vessels. Dorsal aspect target strength estimates of bluefin, obtained from an accompanying 120-kHz echosounder (Simrad EK60), ranged from −33 to −14 dB for fish from 220 to 313 cm (size estimated from commercial catches). Sonar detection ranges were dependent upon sea state and water depth. In rough seas, the surface layer became too turbulent, and air bubble attenuation too high, to consistently separate reverberation from fish-like targets. In shallow water (20–30 m), a range setting of &amp;gt;50 m could not be utilized due to seabed reflections. In water depths &amp;gt;50–60 m, a tilt angle of 7.5o below the horizontal allowed the sonar's range of up to 150 m to be utilized with minimal reverberation from the surface and seabed. The results indicate there is potential for using a 500-kHz multibeam sonar in fishery-independent surveys to monitor and to quantify bluefin in shallow water (&amp;lt;100 m).

V˙O2max Measured with a Self-selected Work Rate Protocol on an Automated Treadmill

The use of graded maximal exercise tests for measuring maximal oxygen consumption (VO2max) is common practice in both cardiopulmonary rehabilitation settings and in sports medicine research. Recent alterations of common testing protocols to allow for self-selected work rates (SPV) have elicited V˙O2max values similar to or higher than more traditional style protocols (TP). Research is lacking in the delivery of the SPV protocol using a treadmill modality. The purpose of the study was to examine the validity of an SPV using an automated treadmill for measuring cardiorespiratory fitness. Thirteen experienced endurance runners completed three maximal exercise tests on a treadmill. Oxygen consumption was measured using a computerized system and averaged more than 30-s time periods. SPV was completed using an automated treadmill that consisted of a sonar range finder, microcontroller, and customized computer software. Subject deviations from the middle of the treadmill belt resulted in rapid, graded increases or decreases in speed. TP was completed on the same treadmill without the use of the automated software. A verification phase protocol (VP) was used to verify if VO2 was maximal. Peak work rate achieved during SPV was significantly greater than that achieved during TP by 1.2 METs; P < 0.05, d = 0.564. Oxygen consumption was significantly greater in TP (64.9 ± 8.2 mL·kg·min) than SPV (63.4 ± 7.8 mL·kg·min); P < 0.005, d = 0.195. An automated treadmill allowed for the completion of SPV similar to what has been reported for cycling. SPV with an automated treadmill did not provide a higher VO2max than TP despite higher work rates.

Simulated Research on Passive Sonar Range Using Different Hydrographic Conditions

As an example using the passive sonar, it calculated the quality factor of passive sonar using the sonar equation. The sound field was calculated under different depth and range using multiform hydrographic conditions. The isoline of passive sonar quality factor was marked out on the sound field. The isoline also represented the passive sonar range. The simulation results showed that hydrographic conditions had important effect on passive sonar range. At the same hydrographic conditions, the permissible drawdown of passive sonar had important effect on passive sonar range. Thus, according to the hydrographic character, the passive sonar range could be improved by selecting suitable passive sonar permissible drawdown.

장애물 위치 정보를 이용한 모바일 로봇의 2차원 지도 작성에 관한 연구

ABSTRACT The purpose of this study is to build and manage environment models with line segments from sonar range data on obstacles in unknown and varied environments. The proposed method therefore employs a two-stage data-transform process in order to extract environmental line segments from range data on obstacles. In the first stage, the occupancy grid extracted from the range data is accumulated to form a two-dimensional local histogram grid. In the second stage, a line histogram extracted from a local histogram grid is based on a Hough transform, and matching serves asa means of comparing each of the segments on a global line segments map against the line segments to detect the degree of similarity inthe overlap, orientation, and arrangement. Each of these tests is formulated by comparing one of the parameters in the segment representation. After the tests, new line segments can be found at maximum-density cells in the line histogram, and they are composed onto the global line segment map. The proposed technique is demonstrated in experiments in an indoor environment.

Narrow-Scope Searching FrFT Method Applied in the Elimination of Sonar Ranging Error

Narrow-Scope Searching FrFT Method Applied in the Elimination of Sonar Ranging Error

Long-term passive acoustic monitoring revealed seasonal and diel patterns of cetacean presence in the Istanbul Strait

The Istanbul Strait (Bosphorus) is a part of the Turkish Straits System, connecting the Aegean Sea and the Black Sea. There are three cetacean species in the Strait, namely the harbour porpoise (Phocoena phocoena), the common dolphin (Delphinus delphis), and the bottlenose dolphin (Tursiops truncatus). To monitor the presence of the cetaceans, a fixed stereo passive acoustic monitoring system (A-tag) was deployed in the middle of the Strait from July 2009 to September 2010. In total 26,814 click trains were detected. Presence, direction and inter-click intervals of phonating cetaceans were measured. Most click trains were detected during the night time. Diel presence pattern was prominent in March and April. In spring, the cetaceans were concentrated in one specific direction from the fixed monitoring system. In contrast, they were found in all directions for the rest of the year. Short range sonar (inter-click intervals (ICIs) less than 50 ms) was commonly detected in spring. During the rest of the year ICIs could reach up to 150 ms. All these findings suggest that they were feeding or socializing in spring and mostly travelling in the other seasons. It is well known that pelagic fish such as sprat and bluefish start their migration from the Aegean Sea to the Black Sea in spring. This study suggests that the cetaceans use the middle part of the Strait for feeding on the pelagic fish in spring when the fish migration has just started.

Room Categorization Based on a Hierarchical Representation of Space

For successful operation in real-world environments, a mobile robot requires an effective spatial model. The model should be compact, should possess large expressive power and should scale well with respect to the number of modelled categories. In this paper we propose a new compositional hierarchical representation of space that is based on learning statistically significant observations, in terms of the frequency of occurrence of various shapes in the environment. We have focused on a two-dimensional space, since many robots perceive their surroundings in two dimensions with the use of a laser range finder or sonar. We also propose a new low-level image descriptor, by which we demonstrate the performance of our representation in the context of a room categorization problem. Using only the lower layers of the hierarchy, we obtain state-of-the-art categorization results in two different experimental scenarios. We also present a large, freely available, dataset, which is intended for room categorization experiments based on data obtained with a laser range finder.

Profile Following for Inspection of Underwater Structures

AbstractWe present a seabed profile estimation and following method for close proximity inspection of 3D underwater structures using autonomous underwater vehicles (AUVs). The presented method is used to determine a path allowing the AUV to pass its sensors over all points of the target structure, which is known as coverage path planning. Our profile following method goes beyond traditional seabed following at a safe altitude and exploits hovering capabilities of recent AUV developments. A range sonar is used to incrementally construct a local probabilistic map representation of the environment and estimates of the local profile are obtained via linear regression. Two behavior-based controllers use these estimates to perform horizontal and vertical profile following. We build upon these tools to address coverage path planning for 3D underwater structures using a (potentially inaccurate) prior map and following cross-section profiles of the target structure. The feasibility of the proposed method is demonstrated using the GIRONA 500 AUV both in simulation using synthetic and real-world bathymetric data and in pool trials.

Intensity and directionality of bat echolocation signals.

The paper reviews current knowledge of intensity and directionality of bat echolocation signals. Recent studies have revealed that echolocating bats can be much louder than previously believed. Bats previously dubbed “whispering” can emit calls with source levels up to 110 dB SPL at 10 cm and the louder open space hunting bats have been recorded at above 135 dB SPL. This implies that maximum emitted intensities are generally 30 dB or more above initial estimates. Bats' dynamic control of acoustic features also includes the intensity and directionality of their sonar calls. Aerial hawking bats will increase signal directionality in the field along with intensity thus increasing sonar range. During the last phase of prey pursuit, vespertilionid bats broaden their echolocation beam considerably, probably to counter evasive maneuvers of eared prey. We highlight how multiple call parameters (frequency, duration, intensity, and directionality of echolocation signals) in unison define the search volume probed by bats and in turn how bats perceive their surroundings. Small changes to individual parameters can, in combination, drastically change the bat's perception, facilitating successful navigation and food acquisition across a vast range of ecological niches. To better understand the function of echolocation in the natural habitat it is critical to determine multiple acoustic features of the echolocation calls. The combined (interactive) effects, not only of frequency and time parameters, but also of intensity and directionality, define the bat's view of its acoustic scene.