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The 2011 International Conference on Multi-functional Materials and Structures Engineering (ICMMSE 2011)

作者： Su Yongzhen Liu Xinwen Li Dayu Wang Xinbing Zhang Yuheng Air Defense Forces Command Academy

Impact localization is one of the major concerns in maintenance of aircraft structures built from composites. A lot of different techniques like acoustic emission, optimization technique based on system are nowadays investigated to identify impact location. But the method to identify impact position in complex composite structure with high accuracy in real time has not been completely established. In the present work, a new efficient method is proposed for identifying impact location in real and complex composite structure based on array signal processing and Lamb waves. There are two steps in the proposed method. The first step is to estimate the directionof-arrival(DOA) of impact source using continuous wavelet transform(CWT) and array signal processing;the second step is to estimate the distance between impact source and the coordinate origin based on propagation characteristic of Lamb wave and CWT. The composite panel with stepped thickness of a real and complex aeronautical tank is used to verify the present methodology. The result shows that the present method may identify impact location fast and accurately.

关键词： array signal processing impact localization Lamb wave composite.

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Maximum a posteriori array signal processing

Maximum a posteriori array signal processing

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International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： N. Owsley Naval Underwater and Systems Center New London CT USA

A noncausal estimator is presented for the position versus time sequence of a source relative to an array of passive receivers. The position is estimated in terms of the bearing and range of the source which are modelled as second order Gauss-Markov discrete time sequences. A maximum a posteriori estimation procedure is developed which provides for an exact nonlinear doppler compensated estimator of the position vector for a batch of received sensor data. The result is a delayed, smoothed position vector for the batch as opposed to a casual estimation filter output sequence. The signal spectrum is also estimated for detection purposes.

关键词： array signal processing Sensor arrays Gaussian processes Delay estimation Motion estimation Phased arrays Maximum a posteriori estimation Filters Maximum likelihood detection Maximum likelihood estimation

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Fly-over Measuring of an Aircraft Landing Gear Noise with array signal processing Technology

Fly-over Measuring of an Aircraft Landing Gear Noise with Ar...

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3rd Asian Pacific Conference on Mechatronics and Control Engineering (APCMCE 2015) and 2nd International Conference on Advanced Materials in Sports Equipment Design (AMSED 2015) and 3rd International Conference on Sport Material, Modelling and Simulation (ICSMMS 2015) and 3rd International Conference on Manufacturing (MANUFACTURING 2015)

作者： Shijie Tu Tao Chen Hang Chen Gang Feng Northwestern Polytechnical University Air Force Engineering University

Two-dimensional mappings of an aircraft landing gear noise was obtained from fly-over measuring by using array signal processing technology, with multi-arms spiral array, the results show: the aircraft landing gear noise is broadband with some single tones, and is concentrated in 1000 Hz below, the noise source was analyzed, supporting landing gear noise reducing design.

关键词： array signal processing Landing gear noise Multi-arms spiral array

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Optimal design of DS-CDMA systems under multipath fading channel: array signal processing approach

Optimal design of DS-CDMA systems under multipath fading cha...

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IEEE Workshop on signal processing Advances in Wireless Communications (SPAWC)

作者： Jui-Chung Hung Bor-Sen Chen Department of Electrical Engineering Hsinchu Taiwan

In this study, based on multirate technique, the detection problem of DS-CDMA systems is transformed to an equivalent signal of beamforming systems. In this situation, the channel plus spreading code in DS-CDMA systems is equivalent to a steering matrix in the signal processing of beamforming systems. Based on an optimum beamforming technique, an optimum detection design is proposed for DS-CDMA systems. Furthermore, stochastic processes model the time-varying tap coefficients of multipath fading channels. The channel parameter or steering matrix estimation algorithm is developed based on the Kalman state estimation method. Finally, an adaptive design for DS-CDMA systems is also discussed in this paper. Consistency of the proposed method is shown, and some illustrative simulations are presented.

关键词： signal design Multiaccess communication Fading array signal processing State estimation AWGN signal processing signal processing algorithms Stochastic processes Kalman filters

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Subspace-based algorithms without eigendecomposition for array signal processing

Subspace-based algorithms without eigendecomposition for arr...

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International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： P. Stoica A. Eriksson T. Soderstrom Systems and Control Group University of Uppsala Uppsala Sweden Department of Automatic Control Polytechnic Institute of Bucharest Romania

A class of subspace-based methods for estimating the direction-of-arrival (DOA) of plane waves impinging on an array of sensors is proposed. The methods estimate the DOA using only linear transformations of the data. This is of special interest for cases when the number of sensors is large and the computational advantages of these methods are significant. These methods use a less restrictive noise model and, e.g., can accommodate cases where the noise variance is different for different sensors. Large sample variance expressions for the estimates of the DOAs are derived, and the statistical properties of the proposed method are compared against the properties of multiple signal classification (MUSIC).< >

关键词： signal processing algorithms array signal processing Sensor arrays Direction of arrival estimation Covariance matrix Multiple signal classification Cost function White noise Additive noise Control systems

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High resolution sensor array signal processing in the beamspace domain: novel techniques based on the poor resolution of Fourier beamforming

High resolution sensor array signal processing in the beamsp...

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Annual ASSP Workshop on Spectrum Estimation and Modeling

作者： M. Zoltowski School of Electrical Engineering Purdue University West Lafayette IN USA

The prospect of sensor array signal processing in beamspace, as opposed to element space, is proposed for the purpose of advantageously exploiting the poor resolution of classical beamforming to convert the element space data vectors to beamspace data vectors having a higher signal/noise ratio and a lower dimensionality. The higher SNR facilities sub-beamwidth resolution capability while the lower dimensionality serves to ease the computational burden typically associated with high-resolution algorithms. Two distinctly different element-space-to-beamspace transformations are presented. The primary application of interest is the low-angle radar tracking problem wherein two signals, the direct and specular path signals, arrive near broadside to the array within a beamwidth of each other.< >

关键词： Sensor arrays signal resolution array signal processing Phased arrays Radar tracking signal to noise ratio signal processing algorithms Maximum likelihood estimation Robustness Multiple signal classification

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Estimation of local displacement vector in random medium utilizing synthetic aperture array signal processing

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JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 2004年第5B期43卷 3103-3106页

作者： Minochi, Y Yagi, S Nishiyama, T Meisei Univ Grad Sch Informat Sci Med Imaging Lab Tokyo 1980052 Japan

Real-time imaging of dynamical movement or stress distribution across living tissues by physiological internal or clinical external stress forces could be a promising toot for clinical diagnosis as visualized palpation. However,. the transversal components of tissue local motion across an ultrasonic beam cannot be obtained utilizing conventional beam scanning. We proposed the combined algorithm of phase sensitive spatial cross-correlation between two sequential speckle echo frames and signal processing for a synthetic aperture of an array transducer which realizes a uniform spatial resolution through, these echo frames. The two-dimensional local motion vector can be directly calculated from the sequentially estimated local phase changes by successive irradiation of different point sources. The accuracy and the statistical variance of the estimated two-dimensional displacement were investigated for the simulated random tissue and the received speckle echo frames from it. The obtained results showed the excellent performance of the proposed algorithm, both for local values and for the entire distribution of estimated displacement vectors throughout the measured medium.

关键词： displacement vector synthetic aperture array signal processing random medium spatial cross-correlation phase difference beam scanning

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The Research of GMD Algorithm for array signal processing Systems

The Research of GMD Algorithm for Array Signal Processing Sy...

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2011 IEEE International Conference on Information Theory and Information Security(ICITIS 2011)

作者： Lizhi Li 1) Zhongtang He 2) Renhui Shi 1) 1) The College of Electronics and Information Engineering Tongji university Shanghai China 2) Xuzhou Airforce College Xuzhou China

GMD algorithm proposed recently can decomposi- tion a ASP channel into multiple identical parallel sub-channels with same SNR. In this paper it derives the di- versity and multiplexing tradeoff curve for GMD scheme. Then compare it to the optimal tradeoff curve and the other two VBLAST schemes. The results in a complete view show that the GMD scheme is superior to the other two VBLAST schemes, but is sub-optimal according to the optimal curve.

关键词： array signal processing diversity and multip- lexing Acoustic Communication

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Large-array signal processing of the discrete spectrum signals: basic aspects and simulations

Large-array signal processing of the discrete spectrum signa...

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International Conference on Antenna Theory and Techniques

作者： E. Gorodetskaya A. Malekhanov Institute of Applied Physics Russian Academy of Science Nizhny Novgorod Russia

signal propagation in various random-inhomogeneous nonstationary environments (in radar, sonars, and wireless communications) leads to loss of the signal coherence in space, time, and frequency. The signal coherence degradation in spatial domain is of particular interest for a large array if its size is greater as compared with the coherence length. Moreover, if a transmission channel is a case of multimode or multipath signal propagation, principal issues of large-array signal processing arise to be concerned with a discrete spatial spectrum of both desired signal and ambient noise. In this report, we give a comparative analysis of large-array signal processing techniques followed the detection problem formulation under such environmental conditions and demonstrate how and why the coherence-reduced discrete spectrum signals in the array input lead to a pronounced hierarchy of their output performances. The focus of our study is a model-based generalization of optimal array processors for the case of multimode signals in multimode noise background and realistic numerical examinations of the large-array gain in random channels, with specific applications to long-range underwater sound. The discrete spectrum signal detection by the use of large arrays is shown to be a specific scenario of array signal processing.

关键词： signal processing array signal processing Spaceborne radar Acoustic noise Working environment noise Radar signal processing Sonar Wireless communication Propagation losses Frequency

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A state space model for H/sup /spl infin// type array signal processing

A state space model for H/sup /spl infin// type array signal...

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International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： T. Ratnarajah A. Manikas Department of Electrical and Electronic Engineering Imperial College of Science Technology and Medicine London UK

The idea of applying H/sup /spl infin// estimation techniques to the "array uncertainties problem" is motivated by the fact that H/sup /spl infin// estimation is robust to model uncertainties and lack of statistical information with respect to noise. A new state space model for the received signal of a general array of sensors is developed which, in contrast to existing models, is capable of handling the simultaneous presence of different type of uncertainties (e.g., gain, phase, locations, mutual coupling, etc. uncertainties). Based on this state space model, formulated in an H/sup /spl infin// framework, two new robust array signal processing techniques have been proposed which mitigate the degrading effects of array uncertainties.

关键词： State-space methods array signal processing Sensor arrays Phased arrays Uncertainty Mutual coupling Direction of arrival estimation Biomedical signal processing Degradation Covariance matrix

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