Article
Chemistry, Analytical
Sunhyo Kim, Sungho Cho, Seom-kyu Jung, Jee Woong Choi
Summary: A method using acoustic intensity for array invariant technique is proposed, which can estimate the source-receiver horizontal range and azimuth to an acoustic source. The feasibility of using a vector quantity for this technique is examined through simulation and acoustic experiment.
Article
Acoustics
D. V. A. N. Ravi Kumar
Summary: The paper introduces an algorithm called Robust Unscented Kalman filter (R-UKF) for underwater passive object/target tracking, which is more efficient than conventional algorithms. The R-UKF algorithm, developed using acoustic signals supplied by a Towed array, applies Estimate Fusion and Measurement Conditioning methods to improve the performance over the base algorithm UKF, as demonstrated through Montecarlo simulations.
Article
Engineering, Aerospace
Tom Northardt
Summary: This article discusses the observability challenge in nonlinear sonar contact tracking and analyzes the utility of an observability criterion in passive sonar tracking with a towed array. The analysis suggests that such criteria are most valuable in applications with minimal navigation perturbations.
IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
(2022)
Article
Chemistry, Analytical
Taeil Suh, Woochan Kim
Summary: The study analyzes the observability and sensor maneuver requirements of a passive target localization system created using conic angle information, satisfying system observability conditions through local linearization approach of the Fisher information matrix. Special cases can mitigate the requirements when the depth difference between the sensor and the target is given. Simulation results demonstrate that sensors following the proposed scheme can obtain meaningful information to estimate 3D target states.
Article
Environmental Sciences
Qisong Wu, Youhai Xu
Summary: This paper proposes an enhanced data-driven shape array estimation scheme and a novel nonlinear outlier-robust particle filter method for acquiring enhanced estimates of time delays in the presence of distorted hydrophone array. The proposed scheme fully exploits directional radiated noise targets as sources of opportunity for online array shape estimation, and utilizes the underlying properties of slowly changing time-delay differences across sensors.
Article
Optics
Zhi Li, Zihan Zang, Zixian Wei, Yaqi Han, Lican Wu, Zhenquan Zhao, Mutong Li, H. Y. Fu
Summary: The infrared optical wireless communication system utilizes passive diffractive optics and virtually imaged phased array technology to achieve multi-user accessibility and high-speed data transmission. By generating multiple beams and tuning the wavelength, the system demonstrates improved performance and flexibility.
Article
Environmental Sciences
Guangbin Zhang, Hengyan Liu, Wei Dai, Tianyao Huang, Yimin Liu, Xiqin Wang
Summary: This paper addresses the problem of locating multiple emitters using distributed passive arrays (sensors) while performing self-calibration to correct possible errors in the assumed array directions. The approach utilizes the geometric consistency of received signals from the same emitter to achieve accurate localization. An atomic norm minimization and group sparsity are employed to promote geometric consistency and align emitter locations.
Article
Fisheries
Robert J. Lennox, Claudia Junge, Jan Reubens, Abdirahman Omar, Ingunn Skjelvan, Knut Wiik Vollset
Summary: The North Sea is a busy and exploited marine area that is home to important species. The 300-km corridor between Norway and Shetland is crucial for ecological and oceanographic research, as it provides insights into species distribution, migratory patterns, and responses to climate and fisheries. Instrumentation in the Bergen-Shetland Corridor would help capture the dynamics of the ocean and its fauna between the North Sea and Norwegian Sea.
FISHERIES OCEANOGRAPHY
(2022)
Article
Acoustics
Florian Meyer, Kay L. Gemba
Summary: This paper introduces a sequential Bayesian estimation method for passive acoustic source localization in shallow water, which associates detected directions of arrival (DOAs) to modeled DOAs and jointly estimates the time-varying source location. The method, with embedded ray tracing, can incorporate environmental parameters to provide robustness. Experimental results demonstrate performance advantages over traditional matched field processing.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2021)
Article
Computer Science, Information Systems
Lijie Wang, Shuang Zhang, Shudong Chen, Chaopeng Luo
Summary: Errors in target localization with traditional magnetic gradient tensor mainly stem from the large error in shallow targets, low signal-to-noise ratio of deep targets' response, and overlapping responses of multiple targets. This study presents an improved magnetic gradient tensor method, utilizing different response signals from various receiving coils to enhance the accuracy of target localization.
Article
Chemistry, Multidisciplinary
Zong-Wei Liu, Chun-Mei Yang, Ying Jiang, Lei Xie, Jin-Yan Du, Lian-Gang Lu
Summary: Array gain is investigated based on fluctuant transmission loss and decrease in spatial coherence in the acoustic channel. An analytical expression is derived to provide insight into gain degradation mechanisms in the ocean waveguide. The formula offers a more accurate method to study array gain, showing previous calculations may be overestimated due to ignoring transmission loss fluctuation.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Electrical & Electronic
Pierre Avital, Gilles Chardon, Jose Picheral
Summary: This paper investigates sampling antennas of an array through a switch on a single receiver channel to reduce costs. It explores the design of switching sequences that impact sine parameter estimation performance, providing design criteria and performance comparisons.
Article
Fisheries
Sai Geetha Seri, Matthew Edward Schinault, Seth Michael Penna, Chenyang Zhu, Lise Doksaeter Sivle, Karen de Jong, Nils Olav Handegard, Purnima Ratilal
Summary: In an experiment in spring 2019, a prototype eight-element coherent hydrophone array was deployed to monitor spawning vocalizations of Norwegian coastal cod. The array recorded cod sounds and analysed their time-frequency characteristics and source level distribution. The study also estimated the spatial dependence of received cod vocalization rates using the array measurements, and found significantly reduced vocalization detection regions in shallow-water areas of the experimental site. The towable hydrophone array proved invaluable in providing continuous spatial coverage and complementing fixed sensor systems.
ICES JOURNAL OF MARINE SCIENCE
(2023)
Article
Physics, Multidisciplinary
Yanting Wu, Jingwen Zou, Chuang Jiang, Xiaohong Li, Shaolin Ke
Summary: This study proposes a method to achieve the direction-dependent non-Hermitian skin effect (NHSE) in a photonic waveguide array through spatially complex modulation. By utilizing complex modulation to induce anisotropic coupling between symmetric and anti-symmetric modes in multimode waveguides, and matching the refractive index of adjacent waveguides, the non-Hermitian Su-Schrieffer-Heeger (SSH) lattice supporting NHSE is realized. The highly unidirectional anisotropic coupling allows mode conversion from antisymmetric modes to symmetric modes only in the forward direction, providing a potential platform for investigating NHSE on photonic chips and finding applications in non-magnetic unidirectional devices.
FRONTIERS IN PHYSICS
(2022)
Article
Engineering, Electrical & Electronic
Nelson J. G. Fonseca
Summary: The waveguide dual-polarization four-way power divider features a novel design with smaller output port spacing at low operating frequencies and excellent performance in the K-band frequency range.
IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS
(2021)