Results 21 to 30 of about 3,240 (206)

Active ABF for sonar [PDF]

open access: yesProceedings of 27th Asilomar Conference on Signals, Systems and Computers, 2002
An adaptive beamforming (ABF) algorithm tailored for active sonar is described. It is especially suited for processing FM waveform received by a fixed or moving sensor array. Adaptation is confined to small windows of time whose duration is closely related to the range resolution of the FM ping.
openaire   +1 more source

Active Control of the Reflection Coefficient of an Underwater Surface

open access: yesAcoustics, 2023
From a strategic point of view, it is essential to protect underwater vehicles from being detected by opponents. Modern mono- or bistatic sonar systems are capable of precisely determining the position of a watercraft.
Johannes Timmermann   +2 more
doaj   +1 more source

Study of reverberation pattern and its cancellation method in shallow water [PDF]

open access: yesTheoretical and Applied Mechanics, 2007
In shallow water, the primary limitation of the performance of active sonar is the reverberation that originates from volume and boundaries scattering as well as multi-path propagation. There­fore, reverberation cancelation is an important research topic
Yang Shiuh-Kuang   +2 more
doaj   +1 more source

Investigation and Numerical Simulation of the Acoustic Target Strength of the Underwater Submarine Vehicle

open access: yesInventions, 2022
Modern weapon systems’ survival hinges on their detection capabilities more than anything else. In the active sonar equation, the acoustic target strength is crucial.
Kaveripakam Sathish   +4 more
doaj   +1 more source

Changes in the acoustic activity of beaked whales and sperm whales recorded during a naval training exercise off eastern Canada

open access: yesScientific Reports, 2022
Experimental research has shown that beaked whales exhibit strong avoidance reactions to naval active sonars used during antisubmarine warfare training exercises, including cessation of echolocation and foraging activity.
Joy E. Stanistreet   +5 more
doaj   +1 more source

A Survey of Underwater Acoustic Data Classification Methods Using Deep Learning for Shoreline Surveillance

open access: yesSensors, 2022
This paper presents a comprehensive overview of current deep-learning methods for automatic object classification of underwater sonar data for shoreline surveillance, concentrating mostly on the classification of vessels from passive sonar data and the ...
Lucas C. F. Domingos   +4 more
doaj   +1 more source

Intelligent Acousto‐Electrical Metamaterials (IAM) for Sound Source Detection

open access: yesAdvanced Materials, EarlyView.
Our proposed metamaterial concept enables sound source detection using a single material, in contrast to conventional arrays that require dozens or even hundreds of transducers. We show that the coupled acoustic–vibrational–electrical responses in piezoelectric metamaterials give rise to topology‐governed charge transport, producing distinct voltage ...
Victor Couëdel   +7 more
wiley   +1 more source

High Stability of Diketopyrrolopyrrole Polymer Transistors Under Aqueous Condition Toward Biosensing Platform

open access: yesAdvanced Materials Technologies, EarlyView.
We are reporting the first‐time investigation of DPP‐based Organic Field‐Effect Transistor (OFET) devices with high‐stability of signal response in both of ambient and aqueous conditions with PBS solution. ABSTRACT Diketopyrrolopyrrole (DPP)–based conjugated polymers show strong promise for electronic applications, including bioelectronic gas sensors ...
Chattarika Khamhanglit   +6 more
wiley   +1 more source

Deep Learning Methods for Assessing Time‐Variant Nonlinear Signatures in Clutter Echoes

open access: yesAdvanced Intelligent Systems, EarlyView.
Motion classification from biosonar echoes in clutter presents a fundamental challenge: extracting structured information from stochastic interference. Deep learning successfully discriminates object speed and direction from bat‐inspired signals, achieving 97% accuracy with frequency‐modulated calls but only 48% with constant‐frequency tones. This work
Ibrahim Eshera   +2 more
wiley   +1 more source

Calculation Method for UKF Target Motion Elements Based on Detection Information of Active and Passive Sonars

open access: yes水下无人系统学报
The target motion element is important information in anti-submarine warfare, and its calculation results have a great influence on the hitting probability of the target, thus affecting combat decision-making.
Hongrui ZHANG   +4 more
doaj   +1 more source

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