This paper considers a two-dimensional direction-of-arrival (DOA) estimation problem from a collaborative, distributed antenna array where each subarray is a distributed sensing node that is arbitrarily oriented. Whil...
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ISBN:
(纸本)9798350329216;9798350329209
This paper considers a two-dimensional direction-of-arrival (DOA) estimation problem from a collaborative, distributed antenna array where each subarray is a distributed sensing node that is arbitrarily oriented. While the relative locations of the subarrays are not precisely known, it is assumed that the configuration of each subarray is locally calibrated whereas the cross-covariance matrix between a pair of distributed nodes includes an unknown phase difference. Without explicitly estimating such unknown phase difference, subspace-based DOA estimation methods fail to coherently utilize the subarrays to locate the DOAs of the impinging signals. We propose a group sparsity-based approach to achieve accurate DOA estimation that is resilient to unknown phase disparities between subarrays. Simulation results clearly illustrate the effectiveness of the group sparsity-based approach using group LASSO, and the superiority over subspace-based methods, such as the MUSIC algorithm, is demonstrated.
distributed array radars consist of multiple sub-arrays separated by tens to hundreds of wavelengths and can match narrow beamwidths with large-aperture, high-gain antennas. The physical independence of the sub-arrays...
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distributed array radars consist of multiple sub-arrays separated by tens to hundreds of wavelengths and can match narrow beamwidths with large-aperture, high-gain antennas. The physical independence of the sub-arrays contributes to significant structure flexibility and is one of the advantages of such radars. However, a typical problem is the grating lobes in the digital beam forming (DBF) beam pattern. Unfortunately, the need to suppress the generation of grating lobes makes the design of acceptable sub-array arrangements very di fficult. A sigma-delta beam former direction of arrival (DOA) estimation method is proposed in this study to solve this problem. The proposed method performs DOA estimation by acquiring the difference signals in addition to the sum signals of all sub-arrays. The difference signal is typically used for monopulse DOA estimation in the phased array radar. The sigma-delta beamformer simultaneously has both advantages of DOA estimations using a distributed array with a large aperture length and using a sub-array that is not affected by the grating lobe. The proposed method can improve the DOA estimation accuracy over the conventional method under grating lobe situations and help the distributed array radar achieve flexibility in the sub-array arrangement. Numerical simulations are presented to verify the effectiveness of the proposed DOA estimation method.
Direction of Arrival (DOA) estimation is important for target detection in the distributed array, however, traditional DOA algorithms based on subspace, such as Multiple Signal Classification algorithm (MUSIC) and Est...
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distributed array consisting of multiple subarrays is attractive for high-resolution direction-of-arrival (DOA) estimation when a large-scale array is infeasible. To achieve effective distributed DOA estimation, it is...
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ISBN:
(纸本)9781665405409
distributed array consisting of multiple subarrays is attractive for high-resolution direction-of-arrival (DOA) estimation when a large-scale array is infeasible. To achieve effective distributed DOA estimation, it is required to transmit information observed at the subarrays to the fusion center, where DOA estimation is performed. For noncoherent data fusion, the covariance matrices are used for subarray fusion. To address the complexity involved with the large array size, we propose a compression framework consisting of multiple parallel encoders and a classifier. The parallel encoders at the distributed subarrays are trained to compress the respective covariance matrices. The compressed results are sent to the fusion center where the signal DOAs are estimated using a classifier based on the compressed covariance matrices.
In this paper, a method of grating lobes and sidelobes suppression for distributed two-level nested array is presented. The method combines the distributed nested array structure and the pattern product theorem to obt...
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ISBN:
(纸本)9781728166704
In this paper, a method of grating lobes and sidelobes suppression for distributed two-level nested array is presented. The method combines the distributed nested array structure and the pattern product theorem to obtain a distributed two-level nested array two-way pattern, which can effectively suppress the grating lobes and sidelobes. The Chebyshev window is used to design the weights of the transmit array pattern to achieve ultralow sidelobes performance. Numerical simulations are provided for testing the proposed method. Simulation results demonstrate the effectiveness of the proposed method, which will help to improve the detection performance of radar.
In this paper, we investigate the problem of direction of arrival (DOA) estimation in phased-array radar. The array consisting of two separated nested subarrays with dual baselines is used to form the DOA problem. And...
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ISBN:
(纸本)9781538661192
In this paper, we investigate the problem of direction of arrival (DOA) estimation in phased-array radar. The array consisting of two separated nested subarrays with dual baselines is used to form the DOA problem. And we present a new DOA estimation method, called weighting signal subspace MUSIC method (WSSMUSIC). By designing the separated nested array and using Khatri-Rao product processing, a large number of virtual array apertures are extended. With the redundancy removal and spatial smoothing, the rank of covariance matrix is restored. The short baseline within subarray yields non-ambiguous coarse DOA estimation by WSSMUSIC. Then the long baseline between subarray yields high accuracy and non-ambiguous DOA estimation by WSSMUSIC searching peak in search region which is determined by coarse DOA and main-lobe region. The virtual extension of aperture can be achieved for this array without increasing the number of sensors and computational complexity compared with traditional uniform linear array. And the proposed algorithm gives significant improvement in DOA estimation performance. The simulation results validate the theoretical algorithm.
To solve the high peak side-lobe level of the distributed array, a hybrid optimization method of particle swarm optimization and convex optimization is proposed in this paper. With the peak side-lobe level as the obje...
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ISBN:
(纸本)9781467376792
To solve the high peak side-lobe level of the distributed array, a hybrid optimization method of particle swarm optimization and convex optimization is proposed in this paper. With the peak side-lobe level as the objective function, the particle swarm optimization is considered as a global optimization algorithm to optimize the elements' positions while the convex optimization is considered as a local optimization algorithm to optimize the elements' weights. In this algorithm, the reducing of the variables' dimensions and the complete match of positions and weights for every particle improve the optimal performance effectively. The results show that for a distributed linear array, the algorithm proposed in this paper can obtain a lower peak side-lobe level under the constraint of main lobe width and limited number of array elements. The better performance of pattern synthesis demonstrates the effectiveness of the algorithm.
To develop a compact distributed array for safe and robust automotive satellite navigation, considerable work on testing prototypes is in progress. Bane scheduling resource-hungry outdoor tests, functionality and robu...
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ISBN:
(纸本)9788831299046
To develop a compact distributed array for safe and robust automotive satellite navigation, considerable work on testing prototypes is in progress. Bane scheduling resource-hungry outdoor tests, functionality and robustness of a Galileo-compatible compact distributed 4-element L-shaped array receiver has been tested against interference in a virtual environment at E5a frequency band. Such an array consisting of compact quarter wavelength sub-arrays distributed over many wavelengths, fed with a decoupling network, mounted in side mirrors of a mock-up car was measured and evaluated with and without a jammer. The effects of automotive mounting location and robustness of the receiver against the jammer have been analyzed in terms of measured radiation patterns and achieved carrier-to-noise-density ratio of the received satellite signals.
We consider the problem of target range-angle imaging using distributed arrays. High resolution imaging requires a large array aperture. However, due to the limited number of array elements, the subarrays are usually ...
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State-of-the-art antenna arrays require a significant installation area when envisaged for compact passenger cars, whose footprint area can be reduced by splitting the full array into two smaller, spatially distribute...
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ISBN:
(纸本)9788831299022
State-of-the-art antenna arrays require a significant installation area when envisaged for compact passenger cars, whose footprint area can be reduced by splitting the full array into two smaller, spatially distributed sub-arrays. The challenge of grating lobes develops while arranging the sub-arrays several wavelengths apart mounted on distant parts of a car. As a consequence, spatial sampling of the incident waves leads to ambiguous direction-of-arrival estimation. An inhomogeneous L-shaped orthogonal arrangement can, however, mitigate such drawbacks to some extent while allowing easier installation. The performance of such an array needs to be tested in a virtual electromagnetic environment in the course of the development process, even long before homologation. An example of such distributed array mounted on a conventional passenger car for satellite navigation is shown in this paper, and the array performance is tested in terms of positioning accuracy in presence of a jammer in our automotive antenna test facility.
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