Results 41 to 50 of about 9,271 (162)

Application research on vector coherent frequency‐domain batch adaptive line enhancement in deep water

IET Radar, Sonar & Navigation
The low frequency line spectrum noise radiated by ships has strong stability and is difficult to eliminate, which is the key information required for passive signal detection.
He Li, Tong Wang, Xinyi Guo, Lin Su, Yaxiao Mo   +4 more
doaj   +1 more source

Low-Frequency Sound Absorption in Air Pipelines and Water-Filled Pipelines Based on Metamaterials

Applied Sciences
Due to the significant impedance mismatch between water and air, two types of pipeline silencers designed for the same target frequency with different filling materials often have significantly different thickness.
Botao Liu, Zigeng Liu, Ang Li, Bo Zheng, Shengchun Liu   +4 more
doaj   +1 more source

Research on High-Precision Long-Range Positioning Technology in the Deep Sea

Journal of Marine Science and Engineering
Conventional acoustic positioning systems are typically confined to regions where direct-path measurements are available. However, in long-range underwater environments, acoustic rays undergo multiple reflections at the sea surface and seafloor ...
Wanting Ming, Dajun Sun, Jucheng Zhang, Yunfeng Han, Kaiyan Tian   +4 more
doaj   +1 more source

Research Progress and Development Trend of Air-Sea Cross-domain Communication

水下无人系统学报
At present, there is an increasing demand for real-time communication and data transmission between the air and the sea. Therefore, it is important to study robust and reliable air-sea cross-domain communication technologies.
Zhigang SHANG, Hongyu ZHANG, Songzuo LIU, Gang QIAO, Han YU, Bailu MIAO, Lu MA, Zhe WANG   +7 more
doaj   +1 more source

Study on Sound Field Properties of Parametric Array Under the Influence of Underwater Waveguide Interface Scattering Based on Non-Paraxial Model—Theory and Experiment

Journal of Marine Science and Engineering
This paper theoretically and experimentally studies the effect of underwater waveguide interface scattering on the nonlinear sound field characteristics of parametric array (PA) radiation.
Yuan Cao, Jie Shi, Jiangyi Zhang, Yuezhu Cheng, Haokang Shi   +4 more
doaj   +1 more source

Covert underwater acoustic communications

The Journal of the Acoustical Society of America, 2010
Low probability of detection (LPD) communications are conducted at a low received signal-to-noise ratio (SNR) to deter eavesdroppers to sense the presence of the transmitted signal. Successful detection at intended receiver heavily relies on the processing gain achieved by employing the direct-sequence spread-spectrum (DSSS) technique.
Jun Ling, Hao He, Jian Li, William Roberts, Petre Stoica   +4 more
openaire   +2 more sources

A Novel Transfer Learning-Based OFDM Receiver Design for Enhanced Underwater Acoustic Communication

Journal of Marine Science and Engineering
The underwater acoustic (UWA) communication system faces challenges due to environmental factors, extensive multipath spread, and rapidly changing propagation conditions.
Muhammad Adil, Songzuo Liu, Suleman Mazhar, Ayman Alharbi, Honglu Yan, Muhammad Muzzammil   +5 more
doaj   +1 more source

Phase Compensation Self-interference Cancellation Method for Full-duplex Single-Carrier Underwater Acoustic Communication

水下无人系统学报
Aiming at the problem that the self-interference cancellation performance is degraded due to the phase mismatch between the transmitting and receiving samples in the in-band full-duplex underwater acoustic communication, this paper proposed a method to ...
Songwen WU, Yinheng LU, Feng ZHOU, Xin QING, Yanlong LI, Zichen ZHAO   +5 more
doaj   +1 more source

The Research on Improved Companding Transformation for Reducing PAPR in Underwater Acoustic OFDM Communication System

Discrete Dynamics in Nature and Society, 2016
To solve the problem of the high peak-to-average power ratio (PAPR) in Orthogonal Frequency Division Multiplexing (OFDM) for the underwater acoustic communication system, the paper offers a method of reducing PAPR which combines the amplitude limiting ...
Jinqiu Wu, Gang Qiao, Xiaofei Qi
doaj   +1 more source

The Structural Types of the Polarization Detection Unit in Imaging Polarimeter Based on the Stokes Parameter Method

Sensors
Bio-inspired imaging polarimeters have significant applications in the field of detecting the polarization state of skylights. The polarization detection principle of polarization detection units in polarimeters is mostly based on the Stokes parameter ...
Yuanhao Li, Xiaohan Guo, Kai Zhang, Xiaoyang Li, Fang Kong, Ziying Jia   +5 more
doaj   +1 more source