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Spectrum Estimation and Modeling, 1988., Fourth Annual ASSP Workshop on

Date 3-5 Aug. 1988

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  • Fourth Annual ASSP Workshop on Spectrum Estimation and Modeling (Cat. No.88CH2633-6)

    Publication Year: 1988
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    Freely Available from IEEE
  • Where do we stand on high resolution in low-angle tracking radar?

    Publication Year: 1988
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (56 KB)

    Summary form only given. Various issues involved in the achievement of high resolution in low-angle tracking radar are reviewed. Particular attention is given to the multipath phenomenon, the use of high-resolution beamforming, estimation techniques, nonredundant arrays, results obtained with a multiparameter adaptive radar system, and future plans for adaptive matched illumination and adaptive di... View full abstract»

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  • High-order spectra of mixture processes

    Publication Year: 1988
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (74 KB)

    Summary form only given. In certain processes higher-order spectra reveal more information than second-order spectra. For example, the bispectrum has been applied to determine deviations from Gaussianness, to determine phase information in nonGaussian linear processes, and in nonlinear interactions. The trispectrum has also been used to extract phase information from nonGaussian signals. For the p... View full abstract»

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  • Subspace linear prediction approach to extracting poles

    Publication Year: 1988, Page(s):367 - 370
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (199 KB)

    It is shown that the conventional linear prediction (LP) methods (including various versions of the Prony method) and the matrix pencil method for extracting poles of data sequences can be unified under a generalized approach called the subspace linear prediction (SLP) approach. The conventional LP methods can be considered as high-order SLP methods, while the matrix pencil method is a first-order... View full abstract»

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  • Robust decentralized direction-of-arrival estimation in the presence of outlier contaminated noise

    Publication Year: 1988, Page(s):117 - 122
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (484 KB)

    A novel scheme for direction-of-arrival estimation is presented. In particular, the authors develop a procedure that provides estimates that are robust against outliers and distributional uncertainties. It also employs decentralized processing such that each subarray provides a set of robust estimates of the directions-of-arrival accompanied by some confidence measures of the estimates. At the fus... View full abstract»

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  • Passive direction-of-arrival and range estimation for near-field sources

    Publication Year: 1988, Page(s):123 - 128
    Cited by:  Papers (44)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (448 KB)

    An algorithm for simultaneously estimating the range and bearing of multiple near-field sources is presented. The method is based on the application of signal subspace ideas to the spatial Wigner-Ville distribution approach originally presented by B.R. Breed and T.E. Posch (Proc. ICASSP'84, p.41B.9.1, 1984). The principal advantages of using signal-subspace methods are that the range/direction-of-... View full abstract»

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  • Reduced-dimension beam-space broad-band source localization: preprocessor design and evaluation

    Publication Year: 1988, Page(s):22 - 27
    Cited by:  Papers (16)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (544 KB)

    A beam-space processor structure is described that reduces the data from element-space to a reduced-dimension beam-space while focusing broadband sources that are within the selected location sector. The objective is principally to reduce the data observation dimension, thereby reducing computation in subsequent source location estimation and focusing sources within the sector. Additional advantag... View full abstract»

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  • Tracking spectral resonances

    Publication Year: 1988, Page(s):49 - 54
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (340 KB)

    An adaptive filter approach that tracks the time-varying parameters of the vocal tract and updates the parameters during the glottal closed phase interval can reduce the formant estimation error. The authors describe three adaptive algorithms for estimating time-varying vocal track parameters: weighted recursive least squared (WRLS), WRLS with variable forgetting factor (WRLS-VFF), and weighted le... View full abstract»

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  • Transform-based covariance differencing approaches to the estimation of multiple-signals in a multi-sensor environment

    Publication Year: 1988, Page(s):327 - 332
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (380 KB)

    Eigendecomposition-based methods developed to date require that the additive noise be spatially white, i.e. of equal power and uncorrelated from sensor to sensor. A set of transform-based covariance differencing approaches is introduced that eliminates the effects of unequal noise power on eigenvalues and, at the same time, increase the resolution of the procedure in comparison with the standard m... View full abstract»

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  • Sliding spectra: a new perspective

    Publication Year: 1988, Page(s):55 - 59
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    The author introduces a simple method that provides an access to a set of sliding power spectra with different characteristics. The method is based on the use of cascading-form realization of the infinite-impulse-response filter. The filter is employed as a time window to the data samples or their lagged products depending on whether the frequency or the power spectrum is of interest. The choice o... View full abstract»

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  • Dominant-mode steered linear prediction for high resolution broadband source location

    Publication Year: 1988, Page(s):28 - 32
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (396 KB)

    The authors develop a linear predictive approach for high-resolution broadband-bearing estimation in low signal-to-noise ratio environments. The proposed technique is based on a space-time statistic called the steered covariance matrix (STCM). In broadband settings, the STCM has an advantage over cross-spectral density matrix in that it can be estimated with much greater statistical stability. The... View full abstract»

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  • Optimal estimates of MA and ARMA parameters of non-Gaussian processes from high-order cumulants

    Publication Year: 1988, Page(s):208 - 212
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB)

    The authors describe an asymptotically minimum-variance algorithm for estimating the moving average (MA) and autoregressive moving average (ARMA) parameters of nonGaussian processes from sample second- and third-order moments. The algorithm uses the statistical properties (covariances and cross-covariances) of the sample moments explicitly. An alternative, simpler algorithm is also presented, whic... View full abstract»

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  • Maximum likelihood estimation of a linearly structured covariance with application to antenna array processing

    Publication Year: 1988, Page(s):172 - 175
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    The author considers the maximum-likelihood (ML) estimation of the covariance of a zero-mean Gaussian random vector from its samples, when the covariance has a certain known structure that typically arises in antenna array processing. Owing to this structure, the conventional sample covariance is no longer the ML estimator. While previous approaches to ML estimation of similar structured covarianc... View full abstract»

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  • Improved high-resolution direction-finding through use of homogeneous constraints

    Publication Year: 1988, Page(s):152 - 157
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    The authors present results that illustrate how incorporation of homogeneous linear constraints can improve the effectiveness of well-known high-resolution direction-finding methods. Results include: the demonstration that the resolution performance of MUSIC can be improved by incorporating suitable constraints; the use of constraints to clarify the relationship between the MUSIC and MinNorm algor... View full abstract»

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  • Adaptive Bayesian spectrum estimation

    Publication Year: 1988, Page(s):33 - 38
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (480 KB)

    A method is described for the numerical analysis of nonstationary signals whose spectral distributions vary slowly enough with time for an adaptive method to be used. The data is processed by blocks. The theory describes the signal by an autoregressive series of high order with stochastic coefficients having a Gaussian distribution. The coefficients are considered as state variables and can thus b... View full abstract»

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  • An algorithm for estimating the time varying AR parameters of a nonstationary process

    Publication Year: 1988, Page(s):60 - 64
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (180 KB)

    A nonstationary scalar random process represented by an autoregressive (AR) model with rapidly time-varying coefficients is considered. Assuming the observation of this AR process is contaminated by additive white Gaussian noise, the authors estimate the coefficients using the Kalman filtering technique and the solution of the Ricatti equation. Computer simulations have shown favorable results tha... View full abstract»

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  • Performance analysis of eigenvector-based high resolution estimators for direction finding in correlated and coherent scenes

    Publication Year: 1988, Page(s):103 - 107
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    The authors present an asymptotic analysis of a class of high-resolution estimators for resolving correlated and coherent plane waves in noise. These estimators are constructed from certain eigenvectors associated with spatially smoothed (or unsmoothed) covariance matrices. The analysis is first carried out for the smoothed case, and from this the conventional MUSIC (unsmoothed) scheme is derived ... View full abstract»

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  • Volume of the space of finite autocorrelations

    Publication Year: 1988, Page(s):283 - 288
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB)

    A method is developed for computing the volume of the space occupied by valid finite autocorrelation sequences of any order p . The method is based on transforming an integral over autocorrelations to an integral over the lattice coefficients of an all-zero filter to order p. The resulting integral was compared numerically using a Monte Carlo method and an importance sampling tec... View full abstract»

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  • The SCORE approach to blind adaptive signal extraction: an application of the theory of spectral correlation

    Publication Year: 1988, Page(s):277 - 282
    Cited by:  Papers (4)  |  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (556 KB)

    A new approach to blind adaption of antenna arrays is presented that has the capability to extract PCM, AM, and FDM-FM communication signals-of-interest (SOIs) from cochannel interference environments using only known spectral correlation properties of those SOIs, i.e. without using knowledge of the antenna array manifold, SOI waveform, or SOI direction-of-arrival to train the array. The class of ... View full abstract»

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  • Uniqueness considerations in autoregressive modeling with third moments

    Publication Year: 1988, Page(s):213 - 216
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB)

    The authors note that Yule-Walker equations for autoregressive (AR) modeling with second-moment (auto-correlation) sequences provide necessary and sufficient conditions for exact matching of the autocorrelation samples of a discrete stationary random process with that of the model. However, when AR modeling is done with linear equations that satisfy the necessary conditions for a match between sam... View full abstract»

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  • Broadband source location using frequency-independent models [spectral estimation]

    Publication Year: 1988, Page(s):13 - 16
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    The author describes a method for locating multiple broadband sources from the signals received on any array of sensors. The key idea is to compute a frequency-dependent spatial model that represents the evolution of the (spatial) wavenumbers associated with each source inside the whole frequency band of interest. The location function is then obtained from the spatial transfer function of this mo... View full abstract»

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  • Robust hyperbolic square root updating in RLS estimation

    Publication Year: 1988, Page(s):301 - 306
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    A stabilized version of the hyperbolic Householder transform method for the multiple vector downdating of Cholesky factors has been developed. This approach offers roughly a twofold savings over schemes based on the multiple application of single-vector downdating schemes, and it is just as stable. The proposed approach is found to exhibit numerical behavior superior to the standard scheme in simu... View full abstract»

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  • High resolution spectral estimation through localized polynomial approximation

    Publication Year: 1988, Page(s):402 - 407
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    Autoregressive-moving-average models are not adequate for most tomographic imaging reconstruction problems. Consequently, the high-resolution capability being sought is lost when these models are used. In this work, a model based on localized polynomial approximation of the spectrum is proposed to solve this class of spectral estimation problems. A method for finding the model parameters is give, ... View full abstract»

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  • Topological approaches to adaptive spectrum modeling

    Publication Year: 1988, Page(s):39 - 43
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (468 KB)

    The authors present initial investigations into a novel approach for adaptive parametric spectrum modeling that is based on numerical continuation methods derived from homotopy theory, a branch of algebraic topology. This initial investigation focuses on homotopies applied to system identification using the linear finite-impulse-response filter structure, to illustrate the transition from homotopy... View full abstract»

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  • Signal enhancement: a useful signal processing tool

    Publication Year: 1988, Page(s):162 - 167
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (548 KB)

    A recently developed signal enhancement algorithm that can significantly improve the performance of many existing signal processing methods is reviewed. In this approach, the data being analyzed are first preprocessed using signal enhancement to clean up the data. This preprocessing operation seeks to modify the data appropriately so that the modified data satisfy known (or hypothesized) signal at... View full abstract»

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