Beamforming with conventional array processing utilizes linear, additive processing techniques to combine the signals from the different array elements. In this project, a multiplicative processing technique is propos...
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ISBN:
(纸本)9781538632840
Beamforming with conventional array processing utilizes linear, additive processing techniques to combine the signals from the different array elements. In this project, a multiplicative processing technique is proposed for combining the signals from antenna arrays for beamforming. The multiplicative processing technique is shown to emulate the performance of larger array apertures than the aperture size of the actual array measurements. Simulations are used to show that the proposed method produces direction-of-arrival (DoA) estimates commensurate with those produced by linear processing of measurements from much larger aperture sizes. It is also shown that the multiplicative processing of measurements from smaller apertures performs as well as linear processing of measurements from larger apertures, for separating signals from multiple sources. The sensitivity of the multiplicative processing technique to noise is also investigated.
Adaptive techniques for detecting small or difficult targets in the midst of high noise and/or clutter have a rich history in the radar array processing community. However, the utility of these schemes is only beginni...
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ISBN:
(纸本)0819459186
Adaptive techniques for detecting small or difficult targets in the midst of high noise and/or clutter have a rich history in the radar array processing community. However, the utility of these schemes is only beginning to be realized for multichannel electro-optical techniques, specifically hyperspectral imaging (HSI). The data products generated by hyperspectral sensors differ greatly from those of radar and sonar arrays, yet recent studies using HSI data have offered promising results for modified versions of common adaptive detectors. In this paper, we compare a series popular adaptive detection schemes applied to HSI data for the task of land mine detection. Experiments using real hyperspectral image cubes, not Simulations, are performed with data from both the visible-SWIR and LWIR regions. Results are presented for different mine types in a variety of scenes.
This paper presents an analysis of different alternatives for the realization of a VLSI cell in a nonlinear neuronal array, based on a simplicial piecewise linear (PWL) operation. Depending on the type of existing des...
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ISBN:
(纸本)9781424453092
This paper presents an analysis of different alternatives for the realization of a VLSI cell in a nonlinear neuronal array, based on a simplicial piecewise linear (PWL) operation. Depending on the type of existing design constraints, namely, speed or density, different bus sizes can be used to broadcast the parameters stored in the memory, and in addition, row and column operations can be serialized. Based on a 90nm technology process, the different options will be analyzed and compared using simulations.
Antenna arrays collect multidimensional data that contains signals arriving from different sources. Neural Network Architectures can separate the different signals, thus enabling parallel processing structures. These ...
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ISBN:
(纸本)0819412767
Antenna arrays collect multidimensional data that contains signals arriving from different sources. Neural Network Architectures can separate the different signals, thus enabling parallel processing structures. These structures can solve a multi-signal estimation problem more efficiently than the corresponding single signal estimator. Various of these parallel architectures are evaluated in the context of array signal processing. Specifically, the scheme developed in this paper (section 2) uses the spatial diversity supplied by the aperture associated with the sensors to separate the signals and to apply them to a bank of parallel adaptive filters. These filters are then designed in accordance with a mean square error minimization criterion (i.e., a criterion based on Second Order Statistics). As Second Order Statistics assume linearity or Gaussianity they are sometimes overly restrictive. It is shown how High Order Statistics can be very useful when more general criteria such as statistical independence between the signals to be separated are imposed.
The performance of high-resolution DOA estimation methods seriously degenerates when there are model errors in array manifold. According to various prior knowledge of array manifold, this paper classifies series of ar...
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ISBN:
(纸本)0780378318
The performance of high-resolution DOA estimation methods seriously degenerates when there are model errors in array manifold. According to various prior knowledge of array manifold, this paper classifies series of array self-calibration methods based on second order statistics, then discusses them and concludes their advantages and disadvantages, finally gives some prospect for research on self-calibration.
The detection of a multi-target scenario in radar-array processing is a crucial step. When only a single source is present, the computationally efficient beamformer for direction-of-arrival (DOA) estimation is suffici...
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The detection of a multi-target scenario in radar-array processing is a crucial step. When only a single source is present, the computationally efficient beamformer for direction-of-arrival (DOA) estimation is sufficient. When multiple sources are present, subspace-based DOA estimation is required to achieve high-resolution and unbiased estimation. To save computational cost, we propose computationally simple criteria for discriminating between a single-target and multi-target scenario in automotive radar-array processing. The suggested criteria can be applied with a single snapshot, and are therefore suitable for classic pulsed radar pre-processing. We present an empirical analysis of the proposed criteria, and show results with real-life data.
The aim of this paper is to present a new method allowing radar digital beamforming (DBF) with only one receiver channel. The key point is the use of a particular spatiotemporal waveform transmitted by an active phase...
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ISBN:
(纸本)0780344286
The aim of this paper is to present a new method allowing radar digital beamforming (DBF) with only one receiver channel. The key point is the use of a particular spatiotemporal waveform transmitted by an active phased array antenna. By properly choosing the temporal modulation applied on each of the transmission elements, one can transmit different signals in different directions, allowing (under certain hypotheses) angular localisation with only one receiver channel. The major advantage is the design of a low cost system providing DBF capabilities.
The main objective in this study is to realize imaging radar of human-body check for security with small number of observation point or array elements. In this paper, we study the application of Khatri-Rao product vir...
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ISBN:
(纸本)9787900914040
The main objective in this study is to realize imaging radar of human-body check for security with small number of observation point or array elements. In this paper, we study the application of Khatri-Rao product virtual array processing to relative near-field SAR data for 2-D imaging. Computer simulation was performed using Beamformer as the imaging method. Simulation results with the mode vector under the far-field approximation and the near-field were compared. The results show that the imaging results can be improved by using the near-field mode vector.
We address the problem of pilot decontamination for massive MIMO systems for finite dimensional channels, wherein the channel vectors between the users and the base station are composed of a finite number of discrete ...
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ISBN:
(纸本)9781479919635
We address the problem of pilot decontamination for massive MIMO systems for finite dimensional channels, wherein the channel vectors between the users and the base station are composed of a finite number of discrete paths. The pilot decontamination problem is addressed using high-resolution parametric spectral estimation methods, such as root multiple-signal classification (root-MUSIC), for resolving paths based on their angle-of-arrivals. The paths corresponding to the desired user are identified based on their amplitudes and then the paths are used to form the channel estimate. Our simulations show an improved performance in terms of bit-error rate compared to the existing approaches in certain critical scenarios.
This paper describes the use of voice activity defector (VAD) in microphone array processing for hand-free systems. Two different types of VAD are proposed using conventional and adaptive beamforming. Taking into acco...
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ISBN:
(纸本)0780375513
This paper describes the use of voice activity defector (VAD) in microphone array processing for hand-free systems. Two different types of VAD are proposed using conventional and adaptive beamforming. Taking into account the fact that the speech signal is not present at all time in human conversations, both signal of interest and noise can be better estimated. Simulation results show that the VAD significantly improves the performance of the array processing algorithms. The performances of the two types of VAD are also compared in the paper.
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