Coherent wideband DOA estimation for non-uniform linear arrays (NLA) is considered. array interpolation is used for two mappings. In the first mapping, NLA is mapped to a uniform linear array with the same array apert...
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ISBN:
(纸本)9781424422401
Coherent wideband DOA estimation for non-uniform linear arrays (NLA) is considered. array interpolation is used for two mappings. In the first mapping, NLA is mapped to a uniform linear array with the same array aperture. In the second mapping covariance matrices for each frequency bin are mapped to a single one at the center frequency for coherent DOA estimation. A Wiener formulation is used for array interpolation where both signal and noise powers are estimated with maximum likelihood method. Different approaches are compared and the advantages of wideband processing versus narrowband processing are outlined. The accuracy of the SNR estimation is high and it is shown that Wiener array interpolation significantly improves the DOA estimation performance in both narrowband and wideband
We consider a calibration problem, where we determine an unknown sensor location using the known track of a calibration target and a known reference sensor location. We cast the calibration problem as a sparse approxi...
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ISBN:
(纸本)9781424422401
We consider a calibration problem, where we determine an unknown sensor location using the known track of a calibration target and a known reference sensor location. We cast the calibration problem as a sparse approximation problem where the unknown sensor location is determined over a discrete spatial grid with respect to the reference sensor. To achieve the calibration objective, low dimensional random projections of the sensor data are passed to the reference sensor, which significantly reduces the inter-sensor communication bandwidth. The unknown sensor location is then determined by solving an l(1)-norm minimization problem (linear program). Field data results are provided to demonstrate the effectiveness of the approach.
We consider the problem of tracking a magnetic target as it travels in a straight-line path in the vicinity of N magnetic sensors. The target is modeled as a magnetic dipole, and we study tracking algorithms when the ...
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ISBN:
(纸本)9781424422401
We consider the problem of tracking a magnetic target as it travels in a straight-line path in the vicinity of N magnetic sensors. The target is modeled as a magnetic dipole, and we study tracking algorithms when the sensors are total-field (scalar) magnetometers and vector magnetometers. A novel, computationally-efficient vector-field algorithm is presented that jointly processes the data from N sensors, yielding estimates of the track and the target dipole moment vector. Simulation examples are included to illustrate the performance of the total-field and vector algorithms.
The performance of most existing arrayprocessing algorithms relies heavily on the precise knowledge of array manifold, which is decided by individual sensor characteristics and array configuration. A major challenge ...
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ISBN:
(纸本)9781424422401
The performance of most existing arrayprocessing algorithms relies heavily on the precise knowledge of array manifold, which is decided by individual sensor characteristics and array configuration. A major challenge for self-calibration techniques is the increased computational burden due to additional perturbation parameters. In this contribution, a novel procedure for array self-calibration is presented. We apply the well known numerical method, the Space Alternating Generalized EM algorithm (SAGE), to simplify the multi-dimensional search procedure required for finding maximum likelihood (ML) estimates. Simulation shows that the proposed algorithm outperforms existing methods that are based on the small perturbation assumption. Furthermore, the proposed algorithm remain robust in critical scenarios including large sensor position errors and closely located signals.
In this paper, an efficient low-complexity robust adaptive beamforming method based on worst-case performance optimization is proposed. Lagrangian method was applied to obtain the expression for the robust adaptive we...
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ISBN:
(纸本)9781424422401
In this paper, an efficient low-complexity robust adaptive beamforming method based on worst-case performance optimization is proposed. Lagrangian method was applied to obtain the expression for the robust adaptive weight vector, which is optimized on the boundary of the steering vector uncertainty region, that is to say, in the worst mismatch case. Combining the constraint condition and the eigendecomposition of the array covariance matrix, root-finding method is used to obtain the optimal Lagrange multiplier. Then, the diagonal loading-like robust weight vector is achieved. ne implementation efficiency is greatly improved since the main computational burden is the eigendecomposition operator. Numerical results show that the performance of the proposed method is nearly identical to the robust Capon beamforming.
We propose a scalable and energy efficient method for reconstructing a 'sparse' Gauss-Markov random field that is observed by an array of sensors and described over wireless channels to a fusion center. The en...
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ISBN:
(纸本)9781424422401
We propose a scalable and energy efficient method for reconstructing a 'sparse' Gauss-Markov random field that is observed by an array of sensors and described over wireless channels to a fusion center. The encoder is universal, i.e. invariant to the statistical model of the source and the channel, and is based on compressed sensing. The reconstruction algorithms exploit the a-priori statistical information about the field and the channel at the fusion center to yield a performance comparable to information theoretic bounds. Furthermore, by putting stringent constraints on the sensing matrix we avoid (or even eliminate) inter-sensor communication while suffering negligible degradation in performance.
In this paper, we propose a new approach to sensor localization problems, based on recent developments in machine leaning. The main idea behind it is to consider a matrix regression method between the ranging matrix a...
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ISBN:
(纸本)9781424422401
In this paper, we propose a new approach to sensor localization problems, based on recent developments in machine leaning. The main idea behind it is to consider a matrix regression method between the ranging matrix and the matrix of inner products between positions of sensors, in order to complete the latter. Once we have learnt this regression from information between sensors of known positions (beacons), we apply it to sensors of unknown positions. Retrieving the estimated positions of the latter can be done by solving a linear system. We propose a distributed algorithm, where each sensor positions itself with information available from its nearby beacons. The proposed method is validated by experimentations.
The problem of optimal node density for ad hoc sensor networks deployed for making inferences about two dimensional correlated random fields is considered. Using a symmetric first order conditional autoregressive Gaus...
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ISBN:
(纸本)9781424422401
The problem of optimal node density for ad hoc sensor networks deployed for making inferences about two dimensional correlated random fields is considered. Using a symmetric first order conditional autoregressive Gauss-Markov random field model, large deviations results are used to characterize the asymptotic per-node information gained from the array. This result then allows an analysis of the node density that maximizes the information under an energy constraints yielding insights into the trade-offs among the information, density and energy.
Subspace estimation is of importance to high-resolution direction estimation in arrayprocessing. In this paper, a new recursive least-squares (RLS) algorithm is proposed for null space estimation, which is used to es...
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ISBN:
(纸本)9781424422401
Subspace estimation is of importance to high-resolution direction estimation in arrayprocessing. In this paper, a new recursive least-squares (RLS) algorithm is proposed for null space estimation, which is used to estimate or track the directions of coherent and/or incoherent signals impinging on a uniform linear array (ULA). Especially by investigating the expectation computation of an inverse matrix, the statistical analysis of the RLS algorithm is studied in the mean and mean-squares senses in stationary environment, and further the mean-square-error (MSE) and mean-square derivation (MSD) learning curves are derived explicitly. The theoretical analyses and effectiveness of the proposed RLS algorithm are substantiated through numerical examples.
In this paper, we propose an estimator of the eigenspectrum of the array observation covariance matrix that builds upon the well-known power method and is consistent for an arbitrarily large array dimension. Tradition...
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ISBN:
(纸本)9781424422401
In this paper, we propose an estimator of the eigenspectrum of the array observation covariance matrix that builds upon the well-known power method and is consistent for an arbitrarily large array dimension. Traditional estimators based on the eigendecomposition of the sample covariance matrix are known to be consistent provided that the number of observations grow to infinity with respect to any other dimension in the signal model. On the contrary, in order to avoid the loss in the estimation accuracy associated with practical finite sample-size situations, a generalization of the conventional implementation is derived that proves to be a very good approximation for a sample-size and an array dimension that are comparatively large. The proposed solution is applied to the construction of a subspace-based extension of the Capon source power estimator. For our purposes, we resort to the theory of the spectral analysis of large dimensional random matrices, or random matrix theory. As it is shown via numerical simulations, the new estimator turns out to allow for a significantly improved estimation accuracy in practical finite sample-support scenarios.
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