• Title, Summary, Keyword: Capon beamforming

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Wideband Capon Beamforming for a Planar Phased Radar Array with Antenna Switching

  • Lee, Moon-Sik
    • ETRI Journal
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    • v.31 no.3
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    • pp.321-323
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    • 2009
  • A wideband beamforming algorithm for estimating the azimuth angle, elevation angle, velocity, and range using a planar phased radar array with antenna switching is proposed. It uses the time-variant steering vector model. Simulation results illustrating the performance of the proposed beamformer are presented.

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A study on wideband adaptive beamforming based on WBRCB for passive uniform line array sonar (WBRCB 기반의 수동 선배열 소나 광대역 적응빔형성 기법 연구)

  • Hyun, Ara;Ahn, Jae-Kyun;Yang, In-Sik;Kim, Gwang-Tae
    • The Journal of the Acoustical Society of Korea
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    • v.38 no.2
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    • pp.145-153
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    • 2019
  • Adaptive beamforming methods are known to suppress sidelobes and improve detection performance of weak signal by constructing weight vectors depending on the received signal itself. A standard adaptive beamforming like the MVDR (Minimum Variance Distortionless Response) is very sensitive to mismatches between weight vectors and actual signal steering vectors. Also, a large computational complexity for estimating a stable covariance matrix is required when wideband beamforming for a large-scale array is used. In this paper, we exploit the WBRCB (Wideband Robust Capon Beamforming) method for stable and robust wideband adaptive beamforming of a passive large uniform line array sonar. To improve robustness of adaptive beamforming performance in the presence of mismatches, we extract a optimum mismatch parameter. WBRCB with extracted mismatch parameter shows performance improvement in beamforming using synthetic and experimental passive sonar signals.

Effective Capon Beamforming Robust to Steering Vector Errors (조향벡터 에러에 강인한 효과적인 Capon 빔 형성기법)

  • Choi, Yang-Ho
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.48 no.5
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    • pp.115-122
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    • 2011
  • Adaptive arrays suffer from severe performance degradation when there are errors in the steering vector. The DCRCB (doubly constrained robust Capon beamformer) overcomes such a problem, introducing a spherical uncertainty set of the steering vector together with a norm constraint. However, in the standard DCRCB, it is a difficult task to determine the bound for the uncertainty, the radius of the spherical set, such that a near best solution is obtained. A novel beamforming method is presented which has no difficulty of the uncertainty bound setting, employing a recursive search for the steering vector. Though the basic idea of recursive search has been known, the conventional recursive method needs to set a parameter for the termination of the search. The proposed method terminates it by using distances to the signal subspace, without the need for parameter setting. Simulation demonstrates that the proposed method has better performance than the conventional recursive method and than the non-recursive standard DCRCB, even the one with the optimum uncertainty bound.

Improving the Performance of the Capon Algorithm by Nulling Elements of an Inverse Covariance Matrix (공분산 역행렬 원소 제거 기법을 이용한 Capon 알고리듬의 성능 개선)

  • Kim, Seong-Min;Kang, Dong-Hoon;Lee, Yong-Wook;Nah, Sun-Phil;Oh, Wang-Rok
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.48 no.5
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    • pp.96-101
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    • 2011
  • It is well known that the Capon algorithm offers better resolution compared to that of the FM (Fourier method) algorithm by minimizing the total output power while maintaining a constant gain in the look direction. Unfortunately, the DoA (Direction of Arrival) estimation performance of the Capon algorithm is drastically degraded when the SNR of received signal is low and thus, it cannot distinguish among signal sources which have similar incidence angles. In this paper, we propose a novel scheme enhancing the resolution of the Capon algorithm by ing all rows except the first row of an inverse covariance matrix.

DOA estimation based beamforming technique for DTV reception performance enhancement (입사각 추정 기반 빔형성을 이용한 DTV 수신성능 개선)

  • 문성훈;한동석
    • Journal of Broadcast Engineering
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    • v.8 no.2
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    • pp.136-145
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    • 2003
  • This paper proposes a DTV receiver using beamforming techniques to improve indoor and mobile reception. The proposed DTV receiver estimates the directions of arrival (DOAs) of incoming signals using Capon's DOA estimation method and generates an adaptive antenna beam pattern to the estimated DOA of the mainpath signal to Improve the channel condition. After beamforming, a following decision feedback equalizer (DFE) removes the remaining multipath components. The proposed receiver can be implemented with a conventional DTV receiver without anymodification. The performance of the proposed receiver is analyzed with modified Brazilian field test models, which include DOA information of Incoming signals. Simulation results show that the proposed receiver can satisfy the threshold of visibility (TOV) when input signal to noise ratio is slightly over 10 dB.

Adaptive Hybrid Beamformer Suitable for Fast Fading (고속 페이딩에 적합한 적응 하이브리드 빔형성기)

  • Ahn Jang Hwan;Han Dong Seog
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.2
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    • pp.49-59
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    • 2005
  • An adaptive hybrid beamformer is proposed to improve the reception performance of the advanced television system committee (ATSC) digital television (DTV) in a mobile environment. Dynamic multipaths and Doppler shifts severely degrade the reception performance of the ATSC DTV receiver. Accordingly, a hybrid beamformer, called a Capon and least mean square (CLMS) beamformer, is presented that uses direction of arrival (DOA) information and the least mean square (LMS) beamforming algorithm. The proposed CLMS algerian efficiently removes dynamic multipaths and compensates for the phase distortion caused by Doppler shifts in mobile receivers. After the CLMS beamformer is operated, the subsequent use of an equalizer removes any residual multipath effects, thereby significantly improving the performance of DTV receivers. The performances of the proposed CLMS, Capon, and LMS beamformersare compared based on computer simulations. In addition, the overall performance of the CLMS beamformer followed by an equalizer is also considered.

Compressive Sensing-Based L1-SVD DOA Estimation (압축센싱기법 기반 L1-SVD 도래각 추정)

  • Cho, Yunseong;Paik, Ji-Woong;Lee, Joon-Ho;Ko, Yo Han;Cho, Sung-Woo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.4
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    • pp.388-394
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    • 2016
  • There have been many studies on the direction-of-arrival(DOA) estimation algorithm using antenna arrays. Beamforming, Capon's method, maximum likelihood, MUSIC algorithms are the main algorithms for the DOA estimation. Recently, compressive sensing-based DOA estimation algorithm exploiting the sparsity of the incident signals has attracted much attention in the signal processing community. In this paper, the performance of the L1-SVD algorithm, which is based on fitting of the data matrix, is compared with that of the MUSIC algorithm.

Eigenspace-Based Adaptive Array Robust to Steering Errors By Effective Interference Subspace Estimation (효과적인 간섭 부공간 추정을 통한 조향에러에 강인한 고유공간 기반 적응 어레이)

  • Choi, Yang-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.4A
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    • pp.269-277
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    • 2012
  • When there are mismatches between the beamforming steering vector and the array response vector for the desired signal, the performance can be severely degraded as the adaptive array attempts to suppress the desired signal as well as interferences. In this paper, an robust method is proposed for the adaptive array in the presence of both direction errors and random errors in the steering vector. The proposed method first finds a signal-plus-interference subspace (SIS) from the correlation matrix, which in turn is exploited to extract an interference subspace based on the structure of a uniform linear array (ULA), the effect of the desired signal direction vector being reduced as much as possible. Then, the weight vector is attained to be orthogonal to the interference subspace. Simulation shows that the proposed method, in terms of signal-to-interference plus noise ratio (SINR), outperforms existing ones such as the doubly constrained robust Capon beamformer (DCRCB).

The Achievable Performance of Unitary-ESPRIT Algorithm for DOA Estimation

  • Satayarak, Peangduen;Rawiwan, Panarat;Supanakoon, Pichaya;Chamchoy, Monchai;Promwong, Sathaporn;Tangtisanon, Prakit
    • Proceedings of the IEEK Conference
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    • pp.1578-1581
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    • 2002
  • In this paper, the accuracy of the direction-of-arrival (DOA) estimation of signal impinged on the uniform linear array (ULA) is investigated. The conventional beamformer and Capon’s beamformer categorized in beamformaing techniques as well as MUSIC (MUlti-pie Signal Classification) and ESPRIT (Estimation of Signal Invariance Techniques) categorized in subspace- based methods are employed to estimate the DOAs. From the simulation result under uncorrelated environment, MUSIC can prominently distinguish the DOAs while the beamforming techniques cannot demonstrate the DOAs as clear as MUSIC does. Moreover, Uni-tary ESPRIT is employed to estimate the DOAs under uncorrelated signal conditions. By means of Uni-tary ESPRIT, the estimation has more accuracy with the computational-time reduction. In addition, it incorporates forward-backward averaging; thus Unitary ES-PRIT can overcome the problem of the coherent signal condition.

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