- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2019 European Space Power Conference (ESPC) - Juan-les-Pins, France (2019.9.30-2019.10.4)] 2019 European Space Power Conference (ESPC) - Electrostatic Discharge Tests for JUICE Photovoltaic Assembly
摘要： A nominally circular 2-D broadband acoustic array of 1.3-m diameter, comprising 508 sensors and associated electronics, was designed, built, and tested for ambient noise imaging (ANI) potential in Singapore waters. The system, named Remotely Operated Mobile Ambient Noise Imaging System (ROMANIS), operates over 25–85 kHz, streaming real-time data at 1.6 Gb/s over a fiber optic link. By using sensors that are much larger than half-wavelength at the highest frequency of interest, so with some directionality, good beamforming performance is obtained with a small number of sensors compared to a conventional half-wavelength-spaced array. A data acquisition system consisting of eight single-board computers enables synchronous data collection from all 508 sensors. A dry-coupled neoprene cover is used to encapsulate the ceramic elements as an alternative to potting or oil filling, for easier maintenance. Beamforming is performed in real-time using parallel computing on a graphics processing unit (GPU). Experiments conducted in Singapore waters yielded images of underwater objects at much larger ranges and with better resolution than any previous ANI system. Although ROMANIS was designed for ANI, the array may be valuable in many other applications requiring a broadband underwater acoustic receiving array.
关键词： broadband array design,Ambient noise imaging (ANI),data acquisition,underwater acoustics
更新于2025-09-23 15:21:01
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High-Speed Plasmonic-Silicon Modulator Driven by Epsilon-near-zero Conductive Oxide
摘要： In this paper, closed-form expressions for the performance of the normalized matched ?lter (NMF) detector are developed speci?cally for the case of large time-bandwidth product, N . As a test case, the task of detecting underwater acoustic signals is considered. While the matched ?lter is the most common detector used, the NMF detector is used in cases where the ambient noise is fast time varying and is hard to estimate. While the performance of the NMF has been studied, no closed-form expressions are given for the detection and false alarm probabilities, and the accuracy of the available approximations greatly deteriorates with N . As a result, evaluating the detection threshold from the receiver operating characteristic requires signi?cant, and sometimes untraceable, numerical calculations. This is speci?cally important for underwater acoustic signals, where due to the low signal-to-noise ratio, N is very large. The analysis performed in this paper solves this problem. The analysis is based on the probability distribution of the NMF to give an exact closed-form (tabulized) expression for the false alarm probability, and a relatively accurate approximation for the probability of detection, both for the large N case. These approximations are found accurate in numerical simulations. Results from an experiment conducted in the Mediterranean sea at the depth of roughly 1000 m validate the analysis.
关键词： false alarm probability,detection probability,detection,Underwater acoustics,matched ?lter,receiver operating characteristic
更新于2025-09-23 15:19:57
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[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Active Plasmonic Sensors for High-sensitivity Microwave Measurements
摘要： A nominally circular 2-D broadband acoustic array of 1.3-m diameter, comprising 508 sensors and associated electronics, was designed, built, and tested for ambient noise imaging (ANI) potential in Singapore waters. The system, named Remotely Operated Mobile Ambient Noise Imaging System (ROMANIS), operates over 25–85 kHz, streaming real-time data at 1.6 Gb/s over a fiber optic link. By using sensors that are much larger than half-wavelength at the highest frequency of interest, so with some directionality, good beamforming performance is obtained with a small number of sensors compared to a conventional half-wavelength-spaced array. A data acquisition system consisting of eight single-board computers enables synchronous data collection from all 508 sensors. A dry-coupled neoprene cover is used to encapsulate the ceramic elements as an alternative to potting or oil filling, for easier maintenance. Beamforming is performed in real-time using parallel computing on a graphics processing unit (GPU). Experiments conducted in Singapore waters yielded images of underwater objects at much larger ranges and with better resolution than any previous ANI system. Although ROMANIS was designed for ANI, the array may be valuable in many other applications requiring a broadband underwater acoustic receiving array.
关键词： data acquisition,Ambient noise imaging (ANI),underwater acoustics,broadband array design
更新于2025-09-19 17:13:59
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Experimental and Theoretical Evidences of Hysteresis in Passive Mode-Locked Quantum Dots Lasers
摘要： In this paper, closed-form expressions for the performance of the normalized matched ?lter (NMF) detector are developed speci?cally for the case of large time-bandwidth product, N . As a test case, the task of detecting underwater acoustic signals is considered. While the matched ?lter is the most common detector used, the NMF detector is used in cases where the ambient noise is fast time varying and is hard to estimate. While the performance of the NMF has been studied, no closed-form expressions are given for the detection and false alarm probabilities, and the accuracy of the available approximations greatly deteriorates with N . As a result, evaluating the detection threshold from the receiver operating characteristic requires signi?cant, and sometimes untraceable, numerical calculations. This is speci?cally important for underwater acoustic signals, where due to the low signal-to-noise ratio, N is very large. The analysis performed in this paper solves this problem. The analysis is based on the probability distribution of the NMF to give an exact closed-form (tabulized) expression for the false alarm probability, and a relatively accurate approximation for the probability of detection, both for the large N case. These approximations are found accurate in numerical simulations. Results from an experiment conducted in the Mediterranean sea at the depth of roughly 1000 m validate the analysis.
关键词： receiver operating characteristic,matched ?lter,detection probability,detection,Underwater acoustics,false alarm probability
更新于2025-09-16 10:30:52
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Hearing the Sounds of Aquatic Life Using Optical Fiber Micro-tip based Hydrophone
摘要： For marine bioacoustics applications, the sounds by aquatic animals must be recorded with high precision and minimal noise in order to extract valuable information. For such marine applications, we propose and demonstrate an optical fiber micro-tip based hydrophone. The hydrophone design consists of an extrinsic Fabry-Perot interferometer which utilizes fiber micro-tip and processed aluminium foil as two partially reflecting mirrors. The packaged optical fiber hydrophone of dimensions 1.4 cm x 1.4 cm x 2 cm, with a microtip diameter of 31.23 μm and natural rubber diaphragm of 6 mm diameter shows a high sensitivity of 8.94 nm/mPa or -41.42 dB re 1 nm/μPa at 1 KHz. The hydrophone shows an excellent signal to noise ratio and the noise-limited minimum detectable pressure is as low as 0.388 μPa/√Hz at 1 KHz. The linear working range of the hydrophone is 0-3950 Hz. The experimental results show that the proposed optical fiber hydrophone can very accurately detect the click trains produced by dolphins for echolocation. Further, depending on the applications, the performance parameters of the proposed hydrophone can be tailored by changing the diaphragm thickness and diameter, thus opening a new platform to study marine environment.
关键词： Optical fibers,Acoustic signal detection,Underwater Optical equipment,Underwater acoustics,fiber sensors
更新于2025-09-11 14:15:04
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Resolving Power of the Interferometric Method of Source Localization
摘要： Results of a computer simulation of the resolution of three noise sources with different intensities against the background of isotropic noise in an oceanic waveguide are presented. A comparative analysis of the error in determining their coordinates (bearing, radial velocity, distance, depth) is performed. A computational experiment is implemented based on the interferometric method of source localization using vector-scalar receivers.
关键词： source localization,vector-scalar receivers,interferometric method,underwater acoustics,oceanic waveguide
更新于2025-09-09 09:28:46