This paper explores the Hybrid Cramer-Rao Lower-bound (HCRLB) for a Gaussian generalized linear estimation problem in which some of the unknown parameters are deterministic while the other are random. In general, the ...
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ISBN:
(纸本)9781424422401
This paper explores the Hybrid Cramer-Rao Lower-bound (HCRLB) for a Gaussian generalized linear estimation problem in which some of the unknown parameters are deterministic while the other are random. In general, the HCRLB on the non-Bayesian parameters is not asymptotically tight. However, we show that for the generalized Gaussian linear estimation problem, the HCRLB of the deterministic parameters coincides with the CRLB, so it is an asymptotically tight bound. In addition, we show that the ML/MAP estimator Ill is asymptotically efficient for the non-Bayesian parameters while providing optimal estimate of the Bayesian parameters. The results are demonstrated on a signalprocessing example. It is shown the Hybrid estimation can increase spectral resolution if some prior knowledge is available only on a subset of the parameters.
Adaptive beamformers operating in snapshot deficient situations often estimate regularization parameters such as the diagonal loading level or the signal subspace dimension. We propose a new beamformer that avoids thi...
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ISBN:
(纸本)9781538647523
Adaptive beamformers operating in snapshot deficient situations often estimate regularization parameters such as the diagonal loading level or the signal subspace dimension. We propose a new beamformer that avoids this problem by computing its array weights as a mixture of the array weights for a set of beamformers. The new beamformer's average output power asymptotically approaches the best performance of any of the beamformers in the set. Applying this technique to the Dominant Mode Rejection (DMR) beamformer obviates the need to estimate the dominant signal subspace dimension. An example simulation of a complicated passive sonar scenario illustrates that the blended beamformer's performance rivals the performance of the best fixed subspace DMR beamformer, and may outperform all of them in nonstationary environments.
The maximum a posteriori penalty function (MAP-PF) approach is applied to three-dimensional (3D) target position tracking of multiple wideband sources using multiple distributed sensorarrays. The track estimation pro...
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ISBN:
(纸本)9781424422401
The maximum a posteriori penalty function (MAP-PF) approach is applied to three-dimensional (3D) target position tracking of multiple wideband sources using multiple distributed sensorarrays. The track estimation problem is formulated directly from the array data using the maximum a posteriori (MAP) estimation criterion. The penalty function (PF) method of nonlinear programming is used to obtain a tractable solution. A sequential update procedure is developed in which penalized maximum likelihood estimates of target directions-of-arrival (DOAs) and spectra are computed at each array and then used as synthetic measurements in a set of extended Kalman filters. The two steps are coupled via the penalty function. The current target states are used to guide the DOA/spectrum estimation, and the estimated signal spectra control the influence of the DOA estimates from each array on the final track estimates. The algorithm can be implemented in a decentralized manner where DOA/spectrum estimation is performed at the arrays, and track estimation is performed at a central processing site.
In this paper we propose an algorithm for angle and polarization estimation of non-coherent sources using real-world polarimetric antenna arrays. In order to construct an accurate model of an antenna array, we exploit...
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ISBN:
(纸本)1424403081
In this paper we propose an algorithm for angle and polarization estimation of non-coherent sources using real-world polarimetric antenna arrays. In order to construct an accurate model of an antenna array, we exploit its Effective Aperture Distribution Function (EADF). This model contains information on the array response for a vertical and horizontal excitation, the directional characteristic of each element, and array imperfections. Here, we propose a method stemming from the RARE (RAnk-Reduction Estimator) algorithm. It performs fast (search-free) DoAs and polarization coefficients estimation. Throughout simulation results, we verify that the algorithm has close to optimal statistical performance with polarimetric real-world arrays. We present the statistical performance for three different array configurations.
In this paper, an extended nested array strategy is proposed for degree of freedom (DOF) enhancement. Based on the augmented nested array (ANA), with the inter-element spacings in the side subarray increased, the stra...
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ISBN:
(纸本)9781728119465
In this paper, an extended nested array strategy is proposed for degree of freedom (DOF) enhancement. Based on the augmented nested array (ANA), with the inter-element spacings in the side subarray increased, the strategy provides the possibility to acquire higher number of DOF than the existing nested-like arrays, such as the nested array, ANA, improved nested array and the maximum inter-element spacing constraint array. The one-side extended nested array (OS-ENA) is specifically proposed based on the ENA strategy, which can successfully avoid the holes brought by the sparse distribution of sensors and increase the DOF. The analytical expressions of sensor locations and DOF are derived. Simulations of the direction-of-arrival estimation verify the superiorities of the proposed OS-ENA with the spacial smoothing MUSIC algorithm used.
We present analytical results which quantify the effect of system mismatch and finite sample support on acoustic vector sensorarray performance. One noteworthy result is that the vector aspect of the array "damp...
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ISBN:
(纸本)9781424422401
We present analytical results which quantify the effect of system mismatch and finite sample support on acoustic vector sensorarray performance. One noteworthy result is that the vector aspect of the array "dampens" the effect of array mismatch, enabling deeper true nulls. This is accomplished because the variance of the vector sensorarray spatial response (due to rotational, positional and filter gain/phase perturbations) decreases in the sidelobes, unlike arrays of omnidirectional hydrophones. When sensor orientation is measured within a reasonable tolerance, the beampattern variance dominates the average sidelobe power response. Our analysis also suggests that vector sensorarray gain performance is less sensitive to rotational than to positional perturbations in the regions of interest. We analytically characterize the eigen-SNR threshold, which depends on the signal and noise covariance and the number of noise-only and signal-plus-noise snapshots, below which (asymptotically speaking) reliable detection using sample eigenvalue based techniques is not possible. Thus for a given number of snapshots, since the dimensionality of the snapshot in a vector sensorarray is larger than that of a hydrophone-only array, the eigen-SNR detection threshold will be greater whenever the eigenvector information is discarded. We present processing techniques customized to the unique characteristics of vector sensors, which exploit information encoded in the sample eigenvectors and are robust to the mismatch and finite sample support issues. These methods include adaptive processing techniques with multiple white noise constraints.
We propose a method of indoor localization using arraysensors. This method uses not only the signal strengths of received signals, but also the spatial information of impinging signals on arraysensors. The signal su...
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ISBN:
(纸本)1424403081
We propose a method of indoor localization using arraysensors. This method uses not only the signal strengths of received signals, but also the spatial information of impinging signals on arraysensors. The signal subspaces, which include information about the strengths and angles of arrival of impinging signals on the arraysensors, are used to identify the location of the terminal. We use the cosines of the principal angles between the signal subspaces of the spatial covariance matrices of the signals received at an array antenna to measure the similarity between signals transmitted from two locations. We conducted an experiment indoors to confirm the validity and effectiveness of our method. The experimental results confirm its effectiveness.
Local processing on the nodes of a distributed sensing and processing system has the benefits of reducing the data volume transferred from the nodes to the fusion center, reducing both transmission power requirements ...
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ISBN:
(纸本)1424403081
Local processing on the nodes of a distributed sensing and processing system has the benefits of reducing the data volume transferred from the nodes to the fusion center, reducing both transmission power requirements and the computational burden on the fusion center. The individual nodes obtain measurements from the environment and transmit a quantized detection statistic to the fusion center. Quantization threshold levels need to be found for each sensor that maximize the performance of the system. We propose a global optimization method, the particle filtering optimization method, that uses particle filtering to propagate the values of the thresholds of a distributed detection system to sensor threshold values that are optimal with respect to some measure of system performance. We demonstrate, through simulations, the effectiveness of the particle filtering optimization method in finding the threshold of each of the sensors used in detection scenario.
The authors examine optimization of the antenna array beamformer bank for a technique to apply coherent signal subspace processing in the beam-space of a bank of true time delay beamformers. This technique offers comp...
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ISBN:
(纸本)9781467310710
The authors examine optimization of the antenna array beamformer bank for a technique to apply coherent signal subspace processing in the beam-space of a bank of true time delay beamformers. This technique offers computational expense advantages over element-space methods, Mean Square Error (MSE) performance similar to wideband coherent subspace techniques and is frequency invariant. This article reports on simulation experiments to improve the true time delay beamformer bank configuration so as to optimize MSE performance of source direction resolution for closely spaced wideband sources. Simulations include pattern search, genetic algorithm and simulated annealing global optimization methods. Results indicate that performance can be significantly improved by applying these methods to the beamformer bank design.
Recently, the authors proposed a miniaturized microphone array not utilizing the phase difference but utilizing the directivity of each microphone, namely aggregated microphones. We have already showed that the phased...
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ISBN:
(纸本)1424403081
Recently, the authors proposed a miniaturized microphone array not utilizing the phase difference but utilizing the directivity of each microphone, namely aggregated microphones. We have already showed that the phased microphone array and the aggregated microphones can be described within the same framework. We have also showed that it is possible to apply the aggregated microphones to the various methods of the phased microphone array. However, the difference of the performance between the phased array and the aggregated microphones has not been evaluated yet. The effect of the directivity and the posture of each microphone on the performance of the aggregated microphones has not also been evaluated yet. In this paper, we evaluate the performance of DCMP (Directionally Constrained Minimization of Power) adaptive array utilizing aggregated microphones.
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