To maintain the stability of the inter-satellite link for gravitational wave detection,an intelligent learning monitoring and fast warning method of the inter-satellite link control system failure is proposed.Differen...To maintain the stability of the inter-satellite link for gravitational wave detection,an intelligent learning monitoring and fast warning method of the inter-satellite link control system failure is proposed.Different from the traditional fault diagnosis optimization algorithms,the fault intelligent learning method pro-posed in this paper is able to quickly identify the faults of inter-satellite link control system despite the existence of strong cou-pling nonlinearity.By constructing a two-layer learning network,the method enables efficient joint diagnosis of fault areas and fault parameters.The simulation results show that the average identification time of the system fault area and fault parameters is 0.27 s,and the fault diagnosis efficiency is improved by 99.8%compared with the traditional algorithm.展开更多
With the purpose of on-line structural health monitoring,a transducer network was embedded into compos- ite structure to minimize the influence of surroundings.The intrinsic dispersion characteristic of Lamb wave make...With the purpose of on-line structural health monitoring,a transducer network was embedded into compos- ite structure to minimize the influence of surroundings.The intrinsic dispersion characteristic of Lamb wave makes the wavelet transform an effective signal processing method for guided waves.To get high precision in feature extrac- tion,an information entropy-based optimal mother wavelet selection approach was proposed,which was used to choose the most appropriate basis function for particular Lamb wave analysis.By using the embedded sensor network and extracting time-of-flight,delamination in the composite laminate was identified and located.The results demon- strate the effectiveness of the proposed methods.展开更多
A credible method of calculating the detection threshold is presented for the multiple target situations, which appear frequently in the lower Doppler velocity region during the surveillance of sea with HF ground wave...A credible method of calculating the detection threshold is presented for the multiple target situations, which appear frequently in the lower Doppler velocity region during the surveillance of sea with HF ground wave radar. This method defines a whole-peak-outlier elimination （WPOE） criterion, which is based on in-peak-samples correlation of each target echo spectra, to trim off the target signals and abnormal disturbances with great amplitude from the complex spectra. Therefore, cleaned background noise samples are obtained to improve the accuracy and reliability of noise level estimation. When the background noise is nonhomogeneous, the detection samples are limited and often occupied heavily with outliers. In this case, the problem that the detection threshold is overvalued can be solved. In applications on experimental data, it is verified that this method can reduce the miss alarm rate of signal detection effectively in multiple target situations as well as make the adaptability of the detector better.展开更多
To detect high frequency （HF） first-order sea echo spectra contaminated with ships, ionosphere interference, and other, a new characteristic-knowledge-aided detection method is proposed. With 2-D image features in r...To detect high frequency （HF） first-order sea echo spectra contaminated with ships, ionosphere interference, and other, a new characteristic-knowledge-aided detection method is proposed. With 2-D image features in range-Doppler spectrum, the trend of first-order sea echoes is extracted as indicative information by a multi-scale filter. Detection rules for both single and splitting first-order sea echoes are given based on the characteristic knowledge combining the indicative information with the global characteristics such as amplitude, symmetry, continuity, etc. Compared with the classical algorithms, the proposed method can detect and locate the first-order sea echo in the HF band more accurately especially in the environment with targets/clutters smearing. Experiments with real data verify the validity of the algorithm.展开更多
Target detection is one of the key technology of precision chemical application.Previously the digital coding modulation technique was commonly used to emit and receive the optical signal in the target detection syste...Target detection is one of the key technology of precision chemical application.Previously the digital coding modulation technique was commonly used to emit and receive the optical signal in the target detection systems previously in China.It was difficult to adjust the output power,and the anti-interference ability was weak in these systems.In order to resolve these problems,the target detection method based on analog sine-wave modulation was studied.The spectral detecting system was set up in the aspects of working principle,electric circuit,and optical path.Lab testing was performed.The results showed that the reflected signal from the target varied inversely with detection distances.It indicated that it was feasible to establish the target detection system using analog sine-wave modulation technology.Furthermore,quantitative measurement of the reflected optical signal for near-infrared and visible light could be achieved by using this system.The research laid the foundation for the future development of the corresponding instrument.展开更多
立足于空间引力波探测对NPRO激光器多频段强度噪声的抑制需求,设计完成一款可用于实现NPRO激光器毫赫兹频段强度噪声和中频段弛豫振荡峰同时探测的低噪声光电探测器。该光电探测器采用零漂移运算放大器与高速运算放大器相结合的电路拓...立足于空间引力波探测对NPRO激光器多频段强度噪声的抑制需求,设计完成一款可用于实现NPRO激光器毫赫兹频段强度噪声和中频段弛豫振荡峰同时探测的低噪声光电探测器。该光电探测器采用零漂移运算放大器与高速运算放大器相结合的电路拓扑结构实现毫赫兹频段内低探测噪声的同时具备15 MHz的探测带宽。该光电探测器的噪声在0.1 m Hz~1Hz频段内的绝对噪声水平低于1×10^(-7)V/Hz^(1/2),在100 k Hz~1 MHz内绝对噪声水平低于2×10^(-8)V/Hz^(1/2)。实测结果显示在0.1 m Hz~1 Hz频段内的绝对噪声水平低于1×10^(-6)V/Hz^(1/2),在100 k Hz~1 MHz内绝对噪声水平低于5×10^(-8)V/Hz^(1/2)。实际噪声水平可满足空间引力波项目对NPRO激光器毫赫兹频段内强度噪声和中频段弛豫振荡峰的探测需求,可用于相关噪声抑制实验研究。展开更多
基金This work was supported by the National Key Research and Development Program Topics(2020YFC2200902)the National Natural Science Foundation of China(11872110).
文摘To maintain the stability of the inter-satellite link for gravitational wave detection,an intelligent learning monitoring and fast warning method of the inter-satellite link control system failure is proposed.Different from the traditional fault diagnosis optimization algorithms,the fault intelligent learning method pro-posed in this paper is able to quickly identify the faults of inter-satellite link control system despite the existence of strong cou-pling nonlinearity.By constructing a two-layer learning network,the method enables efficient joint diagnosis of fault areas and fault parameters.The simulation results show that the average identification time of the system fault area and fault parameters is 0.27 s,and the fault diagnosis efficiency is improved by 99.8%compared with the traditional algorithm.
基金Supported by Natural Science Foundation of China(NSFC No.10702041)NSFC Joint Research Fund for Overseas Chinese Young Scholars(10528206)+1 种基金Key International S&T Cooperation Project of China Ministry of Science and Technnlogy(2005DFA00110)Australian Research Council(Discovery Project).
文摘With the purpose of on-line structural health monitoring,a transducer network was embedded into compos- ite structure to minimize the influence of surroundings.The intrinsic dispersion characteristic of Lamb wave makes the wavelet transform an effective signal processing method for guided waves.To get high precision in feature extrac- tion,an information entropy-based optimal mother wavelet selection approach was proposed,which was used to choose the most appropriate basis function for particular Lamb wave analysis.By using the embedded sensor network and extracting time-of-flight,delamination in the composite laminate was identified and located.The results demon- strate the effectiveness of the proposed methods.
文摘A credible method of calculating the detection threshold is presented for the multiple target situations, which appear frequently in the lower Doppler velocity region during the surveillance of sea with HF ground wave radar. This method defines a whole-peak-outlier elimination （WPOE） criterion, which is based on in-peak-samples correlation of each target echo spectra, to trim off the target signals and abnormal disturbances with great amplitude from the complex spectra. Therefore, cleaned background noise samples are obtained to improve the accuracy and reliability of noise level estimation. When the background noise is nonhomogeneous, the detection samples are limited and often occupied heavily with outliers. In this case, the problem that the detection threshold is overvalued can be solved. In applications on experimental data, it is verified that this method can reduce the miss alarm rate of signal detection effectively in multiple target situations as well as make the adaptability of the detector better.
文摘To detect high frequency （HF） first-order sea echo spectra contaminated with ships, ionosphere interference, and other, a new characteristic-knowledge-aided detection method is proposed. With 2-D image features in range-Doppler spectrum, the trend of first-order sea echoes is extracted as indicative information by a multi-scale filter. Detection rules for both single and splitting first-order sea echoes are given based on the characteristic knowledge combining the indicative information with the global characteristics such as amplitude, symmetry, continuity, etc. Compared with the classical algorithms, the proposed method can detect and locate the first-order sea echo in the HF band more accurately especially in the environment with targets/clutters smearing. Experiments with real data verify the validity of the algorithm.
基金Supported by the National“863”Project of China(2010AA10A301)National Technology Support Project for the 12th Five-year Plan(2011BAD20B07)
文摘Target detection is one of the key technology of precision chemical application.Previously the digital coding modulation technique was commonly used to emit and receive the optical signal in the target detection systems previously in China.It was difficult to adjust the output power,and the anti-interference ability was weak in these systems.In order to resolve these problems,the target detection method based on analog sine-wave modulation was studied.The spectral detecting system was set up in the aspects of working principle,electric circuit,and optical path.Lab testing was performed.The results showed that the reflected signal from the target varied inversely with detection distances.It indicated that it was feasible to establish the target detection system using analog sine-wave modulation technology.Furthermore,quantitative measurement of the reflected optical signal for near-infrared and visible light could be achieved by using this system.The research laid the foundation for the future development of the corresponding instrument.
文摘立足于空间引力波探测对NPRO激光器多频段强度噪声的抑制需求,设计完成一款可用于实现NPRO激光器毫赫兹频段强度噪声和中频段弛豫振荡峰同时探测的低噪声光电探测器。该光电探测器采用零漂移运算放大器与高速运算放大器相结合的电路拓扑结构实现毫赫兹频段内低探测噪声的同时具备15 MHz的探测带宽。该光电探测器的噪声在0.1 m Hz~1Hz频段内的绝对噪声水平低于1×10^(-7)V/Hz^(1/2),在100 k Hz~1 MHz内绝对噪声水平低于2×10^(-8)V/Hz^(1/2)。实测结果显示在0.1 m Hz~1 Hz频段内的绝对噪声水平低于1×10^(-6)V/Hz^(1/2),在100 k Hz~1 MHz内绝对噪声水平低于5×10^(-8)V/Hz^(1/2)。实际噪声水平可满足空间引力波项目对NPRO激光器毫赫兹频段内强度噪声和中频段弛豫振荡峰的探测需求,可用于相关噪声抑制实验研究。
