The detection performance of a towed hydrophone array for deep-diving species is quantified by co... more The detection performance of a towed hydrophone array for deep-diving species is quantified by comparing detections of echolocation clicks from foraging groups of Blainville’s beaked whales (Mesoplodon densirostris) from the TNO Delphinus array to detections from bottom-mounted hydrophones at the Atlantic Undersea Test and Evaluation Center (AUTEC) in the Bahamas. A beaked whale group detection probability of 40% is obtained at close ranges (R<2000m) with the Delphinus towed array, and a maximum detection range of 5000m is measured. The detection function can be explained by models, when taking into account the range in rms source levels (200–220dB re 1μPa2m2), and the high system noise levels during the experiment. The model results suggest that detection ranges up to about 7km are possible under favourable conditions, and demonstrate the effectiveness of using towed arrays to monitor deep-diving species, such as beaked whales.
Journal of the Acoustical Society of America, Dec 1, 2011
The threatened resident beluga population of the St. Lawrence Estuary shares the Saguenay-St. Law... more The threatened resident beluga population of the St. Lawrence Estuary shares the Saguenay-St. Lawrence Marine Park with significant anthropogenic noise sources, including marine commercial traffic and a well-established, vessel-based whale-watching industry. Frequency-dependent (FD) weighting was used to approximate beluga hearing sensitivity to determine how noise exposure varied in time and space at six sites of high beluga summer residency. The relative contribution of each source to acoustic habitat degradation was estimated by measuring noise levels throughout the summer and noise signatures of typical vessel classes with respect to traffic volume and sound propagation characteristics. Rigid-hulled inflatable boats were the dominant noise source with respect to estimated beluga hearing sensitivity in the studied habitats due to their high occurrence and proximity, high correlation with site-specific FD-weighted sound levels, and the dominance of mid-frequencies (0.3–23 kHz) in their noise signatures. Median C-weighted sound pressure level (SPLRMS) had a range of 19 dB re 1 μPa between the noisiest and quietest sites. Broadband SPLRMS exceeded 120 dB re 1 μPa 8–32% of the time depending on the site. Impacts of these noise levels on St. Lawrence beluga will depend on exposure recurrence and individual responsiveness.
The Northern Right Whale (Eubalaena glacialis) is the most endangered large whale species. Collis... more The Northern Right Whale (Eubalaena glacialis) is the most endangered large whale species. Collisions with ships is the cause of a large percentage of documented deaths, and is an inherent problem in the Bay of Fundy in summer and fall, when the whales are in the area. Acoustic methods to detect, localize and track right whales are investigated for the
... Francine Desharnais', Marjo Laurinolli*, Alex Hay2, James A. Theriault' ' Defe... more ... Francine Desharnais', Marjo Laurinolli*, Alex Hay2, James A. Theriault' ' Defence Research Establishment Atlantic, PO Box 1012, Dartmouth, Nova Scotia, Canada ... of the conditions encountered on the date of the pilot study, and the range-independent model SAFARI [18] was ...
... For small error standard deviations E and h, a first-order Taylor series expansion may be use... more ... For small error standard deviations E and h, a first-order Taylor series expansion may be used to obtain the following estimated errors: 112 (cos2 el + cos2 e2)E2 + ( z cos el sin ez cos q5)2h2 180 M 1 sin A01 cos q5 (20) Note ...
Page 1. Shallow-Wat er Low-Frequency Active Sonar Modelling Issues James A. Theriault and Dale D.... more Page 1. Shallow-Wat er Low-Frequency Active Sonar Modelling Issues James A. Theriault and Dale D. Ellis Defence Research Establishme$ Atlantic PO Box 1012 Dartmouth, NS B2Y 327 E-mail: Theriau1tOdrea.dnd.ca Ellis@drea.dnd.ca ABSTRACT ...
Page 1. VOLUME REVERBERATION AND TARGET ECHO CALCULATIONS USING NORMAL MODES Dale D. Ellisl, Terr... more Page 1. VOLUME REVERBERATION AND TARGET ECHO CALCULATIONS USING NORMAL MODES Dale D. Ellisl, Terry J. Deveau2, James A. Theriaultl 1 Defence Research Establishment Atlantic, P. 0. Box 1012, Dartmouth ...
This paper explores the coherent processing of an array of GPS sonobuoys as an effective method f... more This paper explores the coherent processing of an array of GPS sonobuoys as an effective method for enhancing target tracking capabilities and improving the bearing estimation accuracy. The paper mainly focuses on underwater target detection using an array of DIFAR sonobuoys. Currently the bearing estimation of underwater targets using DIFAR sonobuoys field is based on individual element processing. However the
Page 1. Shallow-Wat er Low-Frequency Active Sonar Modelling Issues James A. Theriault and Dale D.... more Page 1. Shallow-Wat er Low-Frequency Active Sonar Modelling Issues James A. Theriault and Dale D. Ellis Defence Research Establishme$ Atlantic PO Box 1012 Dartmouth, NS B2Y 327 E-mail: Theriau1tOdrea.dnd.ca Ellis@drea.dnd.ca ABSTRACT ...
Page 1. VOLUME REVERBERATION AND TARGET ECHO CALCULATIONS USING NORMAL MODES Dale D. Ellisl, Terr... more Page 1. VOLUME REVERBERATION AND TARGET ECHO CALCULATIONS USING NORMAL MODES Dale D. Ellisl, Terry J. Deveau2, James A. Theriaultl 1 Defence Research Establishment Atlantic, P. 0. Box 1012, Dartmouth ...
The problem of target detection and tracking in the ocean environment has attracted considerable ... more The problem of target detection and tracking in the ocean environment has attracted considerable attention due to its importance in military and civilian applications. Sonobuoys are one of the capable passive sonar systems used in underwater target detection. Target detection and bearing estimation are mainly obtained through spectral analysis of received signals. The frequency resolution introduced by current techniques is limited which affects the accuracy of target detection and bearing estimation at a relatively low signal-to-noise ratio (SNR). This research investigates the development of a bearing estimation method using fast orthogonal search (FOS) for enhanced spectral estimation. FOS is employed in this research in order to improve both target detection and bearing estimation in the case of low SNR inputs. The proposed methods were tested using simulated data developed for two different scenarios under different underwater environmental conditions. The results show that the proposed method is capable of enhancing the accuracy for target detection as well as bearing estimation especially in cases of a very low SNR.
The detection performance of a towed hydrophone array for deep-diving species is quantified by co... more The detection performance of a towed hydrophone array for deep-diving species is quantified by comparing detections of echolocation clicks from foraging groups of Blainville’s beaked whales (Mesoplodon densirostris) from the TNO Delphinus array to detections from bottom-mounted hydrophones at the Atlantic Undersea Test and Evaluation Center (AUTEC) in the Bahamas. A beaked whale group detection probability of 40% is obtained at close ranges (R<2000m) with the Delphinus towed array, and a maximum detection range of 5000m is measured. The detection function can be explained by models, when taking into account the range in rms source levels (200–220dB re 1μPa2m2), and the high system noise levels during the experiment. The model results suggest that detection ranges up to about 7km are possible under favourable conditions, and demonstrate the effectiveness of using towed arrays to monitor deep-diving species, such as beaked whales.
Journal of the Acoustical Society of America, Dec 1, 2011
The threatened resident beluga population of the St. Lawrence Estuary shares the Saguenay-St. Law... more The threatened resident beluga population of the St. Lawrence Estuary shares the Saguenay-St. Lawrence Marine Park with significant anthropogenic noise sources, including marine commercial traffic and a well-established, vessel-based whale-watching industry. Frequency-dependent (FD) weighting was used to approximate beluga hearing sensitivity to determine how noise exposure varied in time and space at six sites of high beluga summer residency. The relative contribution of each source to acoustic habitat degradation was estimated by measuring noise levels throughout the summer and noise signatures of typical vessel classes with respect to traffic volume and sound propagation characteristics. Rigid-hulled inflatable boats were the dominant noise source with respect to estimated beluga hearing sensitivity in the studied habitats due to their high occurrence and proximity, high correlation with site-specific FD-weighted sound levels, and the dominance of mid-frequencies (0.3–23 kHz) in their noise signatures. Median C-weighted sound pressure level (SPLRMS) had a range of 19 dB re 1 μPa between the noisiest and quietest sites. Broadband SPLRMS exceeded 120 dB re 1 μPa 8–32% of the time depending on the site. Impacts of these noise levels on St. Lawrence beluga will depend on exposure recurrence and individual responsiveness.
The Northern Right Whale (Eubalaena glacialis) is the most endangered large whale species. Collis... more The Northern Right Whale (Eubalaena glacialis) is the most endangered large whale species. Collisions with ships is the cause of a large percentage of documented deaths, and is an inherent problem in the Bay of Fundy in summer and fall, when the whales are in the area. Acoustic methods to detect, localize and track right whales are investigated for the
... Francine Desharnais', Marjo Laurinolli*, Alex Hay2, James A. Theriault' ' Defe... more ... Francine Desharnais', Marjo Laurinolli*, Alex Hay2, James A. Theriault' ' Defence Research Establishment Atlantic, PO Box 1012, Dartmouth, Nova Scotia, Canada ... of the conditions encountered on the date of the pilot study, and the range-independent model SAFARI [18] was ...
... For small error standard deviations E and h, a first-order Taylor series expansion may be use... more ... For small error standard deviations E and h, a first-order Taylor series expansion may be used to obtain the following estimated errors: 112 (cos2 el + cos2 e2)E2 + ( z cos el sin ez cos q5)2h2 180 M 1 sin A01 cos q5 (20) Note ...
Page 1. Shallow-Wat er Low-Frequency Active Sonar Modelling Issues James A. Theriault and Dale D.... more Page 1. Shallow-Wat er Low-Frequency Active Sonar Modelling Issues James A. Theriault and Dale D. Ellis Defence Research Establishme$ Atlantic PO Box 1012 Dartmouth, NS B2Y 327 E-mail: Theriau1tOdrea.dnd.ca Ellis@drea.dnd.ca ABSTRACT ...
Page 1. VOLUME REVERBERATION AND TARGET ECHO CALCULATIONS USING NORMAL MODES Dale D. Ellisl, Terr... more Page 1. VOLUME REVERBERATION AND TARGET ECHO CALCULATIONS USING NORMAL MODES Dale D. Ellisl, Terry J. Deveau2, James A. Theriaultl 1 Defence Research Establishment Atlantic, P. 0. Box 1012, Dartmouth ...
This paper explores the coherent processing of an array of GPS sonobuoys as an effective method f... more This paper explores the coherent processing of an array of GPS sonobuoys as an effective method for enhancing target tracking capabilities and improving the bearing estimation accuracy. The paper mainly focuses on underwater target detection using an array of DIFAR sonobuoys. Currently the bearing estimation of underwater targets using DIFAR sonobuoys field is based on individual element processing. However the
Page 1. Shallow-Wat er Low-Frequency Active Sonar Modelling Issues James A. Theriault and Dale D.... more Page 1. Shallow-Wat er Low-Frequency Active Sonar Modelling Issues James A. Theriault and Dale D. Ellis Defence Research Establishme$ Atlantic PO Box 1012 Dartmouth, NS B2Y 327 E-mail: Theriau1tOdrea.dnd.ca Ellis@drea.dnd.ca ABSTRACT ...
Page 1. VOLUME REVERBERATION AND TARGET ECHO CALCULATIONS USING NORMAL MODES Dale D. Ellisl, Terr... more Page 1. VOLUME REVERBERATION AND TARGET ECHO CALCULATIONS USING NORMAL MODES Dale D. Ellisl, Terry J. Deveau2, James A. Theriaultl 1 Defence Research Establishment Atlantic, P. 0. Box 1012, Dartmouth ...
The problem of target detection and tracking in the ocean environment has attracted considerable ... more The problem of target detection and tracking in the ocean environment has attracted considerable attention due to its importance in military and civilian applications. Sonobuoys are one of the capable passive sonar systems used in underwater target detection. Target detection and bearing estimation are mainly obtained through spectral analysis of received signals. The frequency resolution introduced by current techniques is limited which affects the accuracy of target detection and bearing estimation at a relatively low signal-to-noise ratio (SNR). This research investigates the development of a bearing estimation method using fast orthogonal search (FOS) for enhanced spectral estimation. FOS is employed in this research in order to improve both target detection and bearing estimation in the case of low SNR inputs. The proposed methods were tested using simulated data developed for two different scenarios under different underwater environmental conditions. The results show that the proposed method is capable of enhancing the accuracy for target detection as well as bearing estimation especially in cases of a very low SNR.
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