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wideband target tracking by using SVR-based sequential Monte Carlo method

SIGNAL processing 2008年第11期88卷 2804-2816页

作者： Kabaoglu, Nihat Cirpan, Hakan A. Maltepe Univ Dept Elect Engn TR-34857 Istanbul Turkey Istanbul Univ Dept Elect & Elect Engn TR-34850 Istanbul Turkey

In this work. a support vector regression (SVR) based sequential Monte Carlo method is presented to track wideband moving sources using a linear and passive sensor array for a signal model based on buffered data. The SVR method is employed together with a particle filter (PF) method to improve the PF tracker performance when a small sample set is available. SVR is used as a sample producing scheme for the current state vector. To provide a good approximation of the posterior density by means of improving the sample diversity, samples (particles) are drawn from an importance density function whose mean and covariance are calculated by using the pre-estimating state vector and the state vector's previous estimate. Thus, a better posterior density than the classical one can be obtained. Simulation results show that the method proposed in this work performs better than the classical one when a small sample set is available. Moreover, the results also show that a modified signal model that utilizes buffering data is superior to the signal model in Ng et al. [Application of particle filters for tracking moving receivers in wireless communication systems, in: IEEE Workshop on Signal processing Advances in Wireless Communications (SPAWC), Rome, Italy, June 2003, pp.575-579]. (C) 2008 Elsevier B.V. All rights reserved.

关键词： wideband array processing target tracking particle filters sequential Monte Carlo support vector machines support vector regression

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wideband modal orthogonality: A New approach for broadband DOA estimation

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SIGNAL processing 2020年 176卷 107696-107696页

作者： Amirsoleimani, Shervin Olfat, Ali Univ Tehran Signal Proc & Commun Syst Lab Tehran Iran

wideband direction of arrival (DOA) estimation techniques for sensors array have been studied extensively in the literature. Nevertheless, needing prior information on the number and directions of sources or demanding heavy computational load makes most of these techniques less useful in practice. In this paper, a low complexity subspace-based framework for DOA estimation of broadband signals, named as wideband modal orthogonality (WIMO), is proposed and accordingly two DOA estimators are developed. First, a closed-form approximation of spatial-temporal covariance matrix (STCM) in the uniform spectrum case is presented. The eigenvectors of STCM associated with non-zero eigenvalues are modal components of the wideband source in a given bandwidth and direction. WIMO idea is to extract these eigenvectors at desired DOAs from the approximated STCM and test their orthogonality to estimated noise subspace. In the non-uniform spectrum case, WIMO idea can be applied by approximating STCM through numerical integration. Fortunately, STCM approximation and modal extraction can be performed offline. WIMO provides DOA estimation without the conventional prerequisites, such as spectral decomposition, focusing procedure and, a priori information on the number of sources and their DOAs. Several numerical examples are conducted to compare the WIMO performance with the state-of-the-art methods. Simulations demonstrate that the two proposed DOA estimators achieve superior performance in terms of probability of resolution and estimation error along with orders of magnitude runtime speedup. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Broadband DOA estimation wideband array processing wideband modal orthogonality

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Single stage DOA-frequency representation of the array data with source reconstruction capability

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SIGNAL processing 2019年 162卷 242-252页

作者： Amirsoleimani, Shervin Olfat, Ali Univ Tehran Signal Proc & Commun Syst Lab Tehran Iran

In this paper, a new signal processing framework is proposed, in which the array time samples are represented in DOA-frequency domain through a single stage problem. It is shown that concatenated array data is well represented in a G dictionary atoms space, where columns of G correspond to pixels in the DOA-frequency image. We present two approaches for the G formation and compare the benefits and disadvantages of them. A mutual coherence guaranteed G construction technique is also proposed. Furthermore, unlike most of the existing methods, the proposed problem is reversible into the time domain, therefore, source recovery from the resulted DOA-frequency image is possible. The proposed representation in DOA-frequency domain can be simply transformed into a group sparse problem, in the case of non-multitone sources in a given bandwidth. Therefore, it can also be utilized as an effective wideband DOA estimator. In the simulation part, two scenarios of multitone sources with unknown frequency and DOA locations and non-multitone wideband sources with assumed frequency region are examined. In multitone scenario, sparse solvers yield more accurate DOA-frequency representation compared to some noncoherent approaches. For non-multitone wideband source scenario, the proposed method with group sparse solver outperforms some existing wideband DOA estimators in low SNR regime. In addition, simultaneous sources' recovery and DOA estimation shows significant improvement compared to the conventional delay and sum beamformer and without prerequisites required in sophisticated wideband beamformers. (C) 2019 Elsevier B.V. All rights reserved.

关键词： DOA-frequency representation Source reconstruction wideband array processing wideband DOA estimation

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Using Multibaseline InSAR to Recover Layovered Terrain Considering wideband array Problem

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IEEE GEOSCIENCE AND REMOTE SENSING LETTERS 2008年第4期5卷 583-587页

作者： Guo, Jiao Li, Zhenfang Bao, Zheng Xidian Univ Natl Lab Radar Signal Proc Xian 710071 Peoples R China

This letter deals with the problems of retrieving height and synthetic aperture radar (SAR) reflectivity of layovered terrain using multibaseline SAR interferometry (InSAR). In particular, we focus on the wideband array problem caused by practically large InSAR arrays and high-resolution SAR images, i.e., the problem of signal envelope misalignment, which is neglected in the work by Gini et al. We propose two methods to eliminate or mitigate the effect of envelope misalignment, one called the aligning method and the other called the joint range cell processing method. In the aligning method, we align each signal envelope for each searched height of the layovered components (i.e., ground resolution cells with different altitudes) during searching procedure. The joint range cell processing method jointly processes the neighboring cells in range to estimate the parameters of layovered components so that the effect of the envelope misalignment can be mitigated. Theoretical analysis and computer simulation results show that both methods have the ability to provide accurate estimation of the heights and radar reflectivities of multiple layovered resolution cells in the presence of large envelope misalignments.

关键词： Beamforming digital elevation model (DEM) direction of arrival (DOA) layover multibaseline synthetic aperture radar interferometry (InSAR) wideband array processing

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Underwater Direction of Arrival Estimation using wideband arrays of Opportunity

Underwater Direction of Arrival Estimation using Wideband Ar...

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OCEANS - Marseille Conference

作者： Dubrovinskaya, Elizaveta Casari, Paolo IMDEA Networks Inst Madrid Spain Univ Carlos III Madrid Madrid Spain

ISBN: (纸本)9781728114507

We present a scheme to estimate the direction of arrival of acoustic signals reflected by underwater targets using wideband hydrophone arrays of opportunity. Such arrays may be obtained by arranging together multiple smaller sub -arrays that were originally designed to work independently. The array of opportunity that results may be subject to practical mounting limitations, hence the typical constraint that closest array elements should not be spaced more than one half-wavelength may not be upheld. In these conditions, the array is affected by spatial ambiguity. Our proposed scheme solves this issue by fusing direction of-arrival information with side information on the estimated target location (obtained via multilateration). This makes it possible to eliminate most of the ambiguity, and yields accurate direction-of-arrival estimates. Our simulation results show that our scheme achieves satisfactory direction of arrival estimation and localization results. Moreover, even by relying on arrays of opportunity, we can outperform classical direction -of-arrival algorithms applied to larger arrays with half-wavelength spacing design.

关键词： wideband array processing underwater acoustic signals direction of arrival estimation side information multilateration localization

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Extreme beam broadening using phase only pattern synthesis

Extreme beam broadening using phase only pattern synthesis

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4th IEEE Sensor array and Multichannel Signal processing Workshop

作者： Brown, George C. Kerce, J. Clayton Mitchell, Mark A. Georgia Inst Technol Georgia Tech Res Inst Sensors & Electromagnet Applicat Lab Atlanta GA 30332 USA

ISBN: (纸本)1424403081

This paper describes methods for broadening the beam of a phased array antenna using phase-only element weights. This type of broadening can be valuable for improving the search occupancy and/or reducing the search frame time for large phased arrays, when transmit beam broadening is combined with multiple simultaneous receive beams. Phase-only broadening is required for typical solid-state (active phased) arrays because control of the transmit amplitude at each element is not practical. A notable result is that there is a relationship between the amount of beam broadening and the efficiency (directivity) of the resulting beam. In particular it is shown that broadening less than similar to 2.5:1 results in reduced beam efficiency for both linear and circular arrays, while a broadening of greater than similar to 2.5:1 results in improved beam efficiency, and that, therefore, certain broadening configurations will be preferable to the radar designer (e.g. 4:1 in one plane rather than 2:1 in two planes, due to a large difference in efficiency). The algorithms used to achieve the broadening patterns presented here are based on a combination of homotopy from known optimality with a stochastic gradient descent approach using a carefully constructed one parameter family of penalty functions.

关键词： pattern synthesis wideband array processing transmit spoiling null control

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Underwater Localization via wideband Direction-of-Arrival Estimation Using Acoustic arrays of Arbitrary Shape

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SENSORS 2020年第14期20卷 3862.-3862页

作者： Dubrovinskaya, Elizaveta Kebkal, Veronika Kebkal, Oleksiy Kebkal, Konstantin Casari, Paolo IMDEA Networks Inst Madrid 28918 Spain Univ Carlos III Madrid Madrid 28918 Spain EvoLogics GmbH D-13355 Berlin Germany Univ Trento Dept Informat Engn & Comp Sci I-38123 Povo TN Italy

Underwater sensing and remote telemetry tasks necessitate the accurate geo-location of sensor data series, which often requires underwater acoustic arrays. These are ensembles of hydrophones that can be jointly operated in order to, e.g., direct acoustic energy towards a given direction, or to estimate the direction of arrival of a desired signal. When the available equipment does not provide the required level of accuracy, it may be convenient to merge multiple transceivers into a larger acoustic array, in order to achieve better processing performance. In this paper, we name such a structure an "array of opportunity" to signify the often inevitable sub-optimality of the resulting array design, e.g., a distance between nearest array elements larger than half the shortest acoustic wavelength that the array would receive. The most immediate consequence is that arrays of opportunity may be affected by spatial ambiguity, and may require additional processing to avoid large errors in wideband direction of arrival (DoA) estimation, especially as opposed to narrowband processing. We consider the design of practical algorithms to achieve accurate detections, DoA estimates, and position estimates using wideband arrays of opportunity. For this purpose, we rely jointly on DoA and rough multilateration estimates to eliminate spatial ambiguities arising from the array layout. By means of emulations that realistically reproduce underwater noise and acoustic clutter, we show that our algorithm yields accurate DoA and location estimates, and in some cases it allows arrays of opportunity to outperform properly designed arrays. For example, at a signal-to-noise ratio of -20 dB, a 15-element array of opportunity achieves lower average and median localization error (27 m and 12 m, respectively) than a 30-element array with proper lambda/2 element spacing (33 m and 15 m, respectively). We confirm the good accuracy of our approach via emulation results, and through a proof-of-concept la

关键词： wideband array processing localization direction of arrival estimation side information clustering multilateration emulation lake experiment

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