Diagonal loading is a commonly used technique that improves the robustness of minimum variance beamformers against multiple impairments. In this paper, we concentrate on the application of diagonal loading to mitigate...
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With the increase in terrorist activities throughout the world, the need to develop techniques capable of detecting radioactive contraband in a timely manner is a critical requirement. The development of Bayesian proc...
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ISBN:
(纸本)9781424417131
With the increase in terrorist activities throughout the world, the need to develop techniques capable of detecting radioactive contraband in a timely manner is a critical requirement. The development of Bayesian processors for the detection of contraband stems from the fact that the posterior distribution is clearly multimodal eliminating the usual Gaussian-based processors. The development of a sequential bootstrap processor for this problem is discussed and shown how it is capable of providing an enhanced signal for eventual detection.
Distributed signalprocessing techniques for classification of objects are studied assuming knowledge of sensor measurement statistics. The spatio-temporal signal field generated by an object is modeled as a bandlimit...
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Distributed signalprocessing techniques for classification of objects are studied assuming knowledge of sensor measurement statistics. The spatio-temporal signal field generated by an object is modeled as a bandlimited stationary ergodic Gaussian field. The model. suggests a simple abstraction of correlation between node measurements: it partitions the network into disjoint spatial coherence regions over which the signal remains strongly correlated, whereas the signal in distinct coherence regions is approximately uncorrelated. The size of coherence regions is determined by spatial signal bandwidths. It is shown that this partitioning imposes a structure on optimal distributed classification algorithms that is naturally suited to the communication constraints of the network: local high-bandwidth exchange of feature vectors within each coherence region to improve the measurement signal-to-noise ratio (SNR), and global low-bandwidth exchange of local decisions across coherence regions to stabilize the inherent variability in the signal. Classifier performance is analyzed for both soft and hard decision fusion across coherence regions assuming noise-free, as well as noisy communication links between nodes. Under mild conditions, the probability of error of all classification schemes (soft, hard, noisy) decays exponentially to zero with the number of independent node measurements.-the error exponent depends on both the measurement and communication SNRs and decreases from soft to hard to noisy, fusion. Numerical results based on real data illustrate the remarkable advantage of multiple sensor measurements in distributed decision making.
This paper presents a time-reversal based approach for detecting the positions of subsurface passive targets like landmines. The measurements are made by using sources andsensors placed on the surface. The imaging al...
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Two data alignment based widely linear (WL) beamformers are proposed for the extraction of a widebandsignal of interest (SOI) contaminated by sensor noise and wideband interferences. Both beamformers are designed und...
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ISBN:
(纸本)9781728151021
Two data alignment based widely linear (WL) beamformers are proposed for the extraction of a widebandsignal of interest (SOI) contaminated by sensor noise and wideband interferences. Both beamformers are designed under the criterion of linearly constrained minimum variance, applied to the aligned and (conjugate) augmented array output. The first beamformer requires no prior knowledge/estimation of any SOI noncircularity parameter, while the second one requires the prior knowledge/estimation of the SOI noncircularity phase. For the practical realization of the second beamformer, two pre-processing based schemes are developed for estimating the needed SOI noncircularity phase (the SOI noncircularity rate is assumed to be known in advance). The efficacy of the presented wideband WL beamformers has been verified by simulation results.
In this paper, single snapshot direction-of-arrival (DOA) estimation under mutual coupling (MC) is considered with arbitrary array structures. A compressed sensing approach is utilized and a joint-sparse recovery algo...
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A method is proposed for reducing the effect of white noise in wideband uniform linear arrays via a combination of a judiciously designed transformation followed by highpass filters. The reduced noise level leads to a...
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The partial discharge ultrasonic array positioning technique combines the sensorarray with the arraysignalprocessing method. In this paper, the Extrinsic Fabry-Perot Interferometric optical fiber ultrasonic sensor ...
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ISBN:
(纸本)9781538685495
The partial discharge ultrasonic array positioning technique combines the sensorarray with the arraysignalprocessing method. In this paper, the Extrinsic Fabry-Perot Interferometric optical fiber ultrasonic sensor was used. It has the high sensitivity and is not affected by electromagnetic interference. And take full advantage of the EFPI sensor what can be placed in the oil to improve the array structure. First a four-element EFPI ultrasonic sensorarray of regular tetrahedral structure was designed, which was placed in the fuel tank to detect the local ultrasonic signal. Then, the MUSIC algorithm was used to measure the local discharge source;and compared result with the 2x2 planar array. Finally, the correction is performed for the position error of the array element. The results show that the EFPI sensor stereo array can detect the partial discharge signal with high SNR in the oil, and has higher direction finding accuracy than traditional planar arrays. Especially in the aspect of array blind zone, the stereo array can effectively realize spatial multi-angle source direction finding. And TCT algorithm is used to correct the position error of the array element, which improves the direction finding accuracy, and satisfy the actual project needs.
We address the problem of estimating the harmonics of a two-dimensional exponential mixture. A new algorithms that exploits the multiple-invariance structure is proposed. Unlike previous ESPRIT type methods for two- o...
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作者:
Le Lance, Q.Kaplan, M.McClellan, J.H.Dept. of Computer Science
Center for Theoretical Studies of Physical Systems Clark Atlanta University AtlantaGA30314 United States Dept. of Engineering
Center for Theoretical Studies of Physical Systems Clark Atlanta University AtlantaGA30314 United States CSIP
School of Elec. and Comp. Eng. Georgia Institute of Technology AtlantaGA30332-0250 United States
This work investigates different methods to track a target using bearing measurements for a large number of sensor nodes. The performances of the tracking methods: linear Kalman filtering (LKF), extended Kalman filter...
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