Results 61 to 70 of about 1,483 (184)

Visualisation forms in passive sonar with towed array

Archives of Acoustics, 2014
This paper presents forms of visualisation used in modern underwater systems, a topic covered at two previous Seminars. This year’s presentation describes how imaging is organised on the monitors of a passive sonar with a long acoustic array, towed ...
A. Raganowicz, L. Kilian, J. Marszal, Z. Ostrowski, A. Schmidt   +4 more
doaj  

Machine Learning Ship Classifiers for Signals from Passive Sonars

Applied Sciences
The accurate automatic classification of underwater acoustic signals from passive SoNaR is vital for naval operational readiness, enabling timely vessel identification and real-time maritime surveillance.
Allyson A. da Silva, Lisandro Lovisolo, Tadeu N. Ferreira   +2 more
doaj   +1 more source

Resolution capabilities of passive sonar receiving arrays [PDF]

The Journal of the Acoustical Society of America, 1975
Resolution is defined as a binary hypothesis test or detection problem using the formulation of Rockmore and Bershad [J. Acoust. Soc. Am. 58, 684–692 (1975).] The formulation assumes Gaussian random signal and noise. The sufficient statistic, from the likelihood ratio, is compared with a threshold to determine whether the signal is from one or two ...
openaire   +1 more source

Hybrid Log-Mel and HPSS-Aided Convolutional Neural Network for Underwater Very-Low-Frequency Remote Passive Sonar Detection

Journal of Marine Science and Engineering
Very-low-frequency (VLF) passive sonar detection is one of the core technologies for maritime surveillance, although its performance is often severely affected by strong impulsive ocean ambient noise interference. This paper, for the first time, proposes
Haitao Dong, Lijian Yang, Yuan Liu, Siyuan Li   +3 more
doaj   +1 more source

Preprocessing passive sonar signals for neural classification

IET Radar, Sonar & Navigation, 2011
The noise radiated from ships in the ocean contains information about their machinery and can be used for detection and identification purposes. Here, a preprocessing method is developed in order to improve the performance of a feedforward neural network, which is used to classify four classes of ships.
W.S. Filho, J.M. de Seixas, N.N. de Moura   +2 more
openaire   +1 more source

Acoustical characteristic predictions of a multi-layer system of a submerged vehicle hull mounted sonar simplified to an infinite planar model

International Journal of Naval Architecture and Ocean Engineering, 2012
Hull Mounted Sonar (HMS) is a long range submerged vehicle's hull-mounted passive sonar system which detects low-frequency noise caused by machineries of enemy ships or submerged vehicles.
Sung-Hee Kim, Suk-Yoon Hong, Jee-Hun Song, Hyun-Gwon Kil, Jae Jin Jeon, Young-Soo Seo   +5 more
doaj   +1 more source

A Dynamic Evaluation Method for Collaborative Search Efficiency of Multi-Sonar Systems Under Uncertain Situations

Applied Sciences
In sonar collaborative search tasks, effectively evaluating the collaborative search efficiency is an important way to measure whether a task can be successful, which can also provide strong support for optimizing search schemes.
Shizhe Wang, Weiyi Chen, Zongji Li, Xu Chen   +3 more
doaj   +1 more source

Geometric Approach to Passive Ranging in Underwater Localization Systems

IEEE Access, 2018
The use of underwater surveillance systems is critical for effective command of maritime power. Ships or submarines equipped with active sonar systems emit sounds to obtain range or angle information.
Yu-Chien Lin, Hsin-Jung Chen, Wei-Ho Chung, Ta-Sung Lee   +3 more
doaj   +1 more source

Robust Target Tracking with Multi-Static Sensors under Insufficient TDOA Information

Sensors, 2018
This paper focuses on underwater target tracking based on a multi-static sonar network composed of passive sonobuoys and an active ping. In the multi-static sonar network, the location of the target can be estimated using TDOA (Time Difference of Arrival)
Hyunhak Shin, Bonhwa Ku, Jill K. Nelson, Hanseok Ko   +3 more
doaj   +1 more source

Enhanced LOFAR Detection Processing for Passive SONAR

Defence Science Journal
This study surveys methods for improvements in the processing and visualization of Low Frequency Analysis and Recording (LOFAR) in sonar systems. The surveyed method employs a weighted Fast Fourier Transform (FFT) technique to compute LOFAR (Low Frequency Analysis and Recording) spectrum, with the weighting function inversely proportional to the ...
null Deepa B, null Murali Krishna P, null Sooraj K. Ambat   +2 more
openaire   +1 more source