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An efficient sparsity-inducing method for direction-of-arrival (DOA) estimation is proposed to solve the challenging problem of computation cost and resolution. Element-space is firstly mapped to beamspace by using the beamforming matrix, and then the array covariance matrix is used for sparse representation. In doing so, the sparse Bayesian learning (SBL) technique is applied to enforce sparsity...
As for a compact Uniform Circular Array (UCA), the performance of Beam forming (BF) or Direction-of-Arrival (DOA) estimation will be severely degraded by strong electromagnetic mutual coupling effect, and the calibration method based on Rank Reduction (RARE) lacks robustness. Based on the special circular symmetry of a UCA, a new efficient and robust method is proposed to calibrate the mutual coupling...
A low computation complexity algorithm for single source three dimensional (3-D) localization of multiple-input multiple-output (MIMO) radar with uniform circular transmit array is presented in this letter. The direction of departure (DOD) and the direction of arrival (DOA) are estimated respectively. Based on the geometry of MIMO radar, the 3-D coordinates of target are calculated. The proposed algorithm...
The paper considers the problem of how to simultaneously estimate the direction-of-arrival (DOA) of a source signal and the phase error of a uniform linear array (ULA). We introduce a new method to estimate those parameters for a partly calibrated ULA. As its name suggests, partly calibrated ULA means a array with some of its sensor elements have been calibrated. In particular, our method can be well...
In this paper, advanced directional networking technology is proposed which achieves full directional capability using physical layer assets including propagation modeling and sets of directional antennas. In the proposed approach each node, referred to as an advanced node, consists of an appropriately timed scanning array for mobile user discovery, a dynamically beamformed array for communication...
In millimeter wave (mmWave) systems adopting large number of antennas at both the transmitter and the receiver, channel estimation is challenging due to the large number of antennas and low signal-to-noise ratio (SNR) before beamforming. Due to the sparse nature of mmWave channels, the channel estimation can be solved by beam search. While conventional beam search schemes rely on exhaustive training,...
Mainlobe cancellation refers to an advanced technique with the salient feature of maintaining the monopulse angle estimation accuracy of the target while canceling a mainlobe jammer. This technique makes use of the high-gain monopulse beams including the delta-delta beam for jamming cancellation. The technique is based on an orthogonal nulling concept where jamming is canceled in one angular domain...
A new robust adaptive beamforming based on phase extraction is proposed in this paper. The steering vector (SV) is firstly estimated by iterative procedure, and then the angle sector of the desired signal can be determined by using the phase information of the estimated SV. By using the estimated angle sector, the interference-plus-noise covariance matrix can be calculated by Capon spectral integration...
An enhanced array processing architecture using adaptive digital beamforming at subarray level is proposed for monopulse angle estimation in presence of mainlobe and sidelobe jammings. First, in order to reduce the receiver count, fixed analog beamforming is performed at element level and sub-array outputs are converted to digital signals. Then, adaptive row and column digital beams are formed at...
Direction of arrival (DOA) estimation is of great importance to signal processing, and, as a consequence, various arrays have recently been studied to get good DOA estimation performance. Particularly, spherical arrays have the advantage of three-dimensional orientation which benefits three-dimensional processing and analysis. Also, spherical symmetric structure of spherical arrays could promote the...
Traditional spatial sparse techniques for DoA estimation are implemented by full arrays. However in practice, it is desirable to use as few sensors as possible to reduce the cost for manufacturing the array or to counter against sensor failure. As a result, joint optimisation of sparse array and spatial sparsity becomes an ideal alternative. In most of existing methods, these two kinds of sparsity...
An attempt to record speech signals using an array of directional microphones carried by an unmanned aerial vehicle (UAV) is reported. The speech enhancement algorithm estimates the power spectral densities (PSD) of the target speech and rotor noise which are used to calculate a Wiener filter for extracting the target speech. The calculated Wiener filter is then applied to the output of a beamforming...
The Wiener filter has been used as a post-filter applied to the output of beamforming, which boosts the overall performance of sound source enhancement. Since the power spectral density (PSD) of each sound source needs to be estimated to derive the Wiener filter, a previous study attempted to estimate source PSDs from the output signals of multiple beamformings using linear approximation realized...
Microphone array Wiener filtering has been studied for practical sound source enhancement in noisy environments. In our previous work, the power spectral density (PSD)-estimation-in-beamspace method was proposed for estimating PSDs of target sources and surrounding noises. Assuming that source signals are uncorrelated with each other, the relationships among the PSDs of multiple beamforming outputs...
Although the minimum variance (MV) beamformer can provide enhancement in both resolution and contrast of ultrasound images when compared with conventional delay-and-sum (DAS) beamforming, its clinical application is limited by its sensitivity to phase aberrations. Several robust MV beamformers have been proposed, but present limitations when faced with second order phase aberration. Additionally,...
Directional beamforming (DB) estimates blood flow velocities accurately when the flow angle is known. However, for automatically finding the flow angle a computationally expensive approach is used. This work presents a method for estimating the flow angle using a combination of inexpensive transverse oscillation (TO) estimators and only 3 directional beamformed lines. The suggested DB vector flow...
Experimental 3-D vector flow estimates obtained with a 62+62 2-D row-column (RC) array with integrated apodization are presented. A transverse oscillation (TO) velocity estimator is implemented on a 3.0 MHz RC array, to yield real-time 3-D vector flow in a cross-sectional scan plane at 750 frames per second. The method is validated in a straight-vessel phantom (Ø = 8 mm) connected to a flow pump capable...
In this papers we address the optimal power allocation problem in a distributed passive radar sensor network system, where closely located nodes are capable of distributed beamforming. In this setup, the network of sensor nodes is viewed as a combination of node clusters, where each cluster is capable of time synchronization, and coordinated transmission. The goal of the network is to provide a reliable...
A robust blind beamforming algorithm is proposed for Long Term Evolution (LTE) system in the uplink direction using a Uniform Linear Array (ULA) at the base station (eNodeB) in the multipath environment. There is no information about the incoming signals, so a robust estimation of the Direction of Arrival (DOA) of the received signals is performed first. The robust Re-iterative Superresolution (RISR)...
We present the design of a digital microphone array comprised of MEMS microphones and evaluate its potential for spatial audio capturing and direction-of-arrival (DOA) estimation which is an essential part of encoding the soundscape. The device is a cheaper and more compact alternative to analog microphone arrays which require external — and usually expensive — analog-to-digital converters and sound...
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