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In this paper, we present a method for estimating the signal sources steering vector using an arbitrary planar array with omnidirectional elements. The proposed method improves the initial estimation of the signal steering vector in two steps. In the first step of this algorithm we minimize of the distance between the steering vector and the signal subspace. The second step improves the estimation...
In this paper, we have chronicled the development of sound localization system based on TDOA (Time Difference of Arrival). Acoustic Source Localization (ASL) is a technique used to track and locate the exact location of a sound source using an array of microphones. The concept of ASL uses sound signals captured from an array of microphones and they are processed using TDOA localization method to estimate...
This paper addresses sound source detection in an outdoor environment using a quadrotor with a microphone array. Since the previously reported method has a high computational cost, we proposed a sound source detection algorithm called MUltiple SIgnal Classification based on incremental Generalized Singular Value Decomposition (iGSVD-MUSIC), which detects sound source location and temporal activity...
Adaptive equalization is a widely used method of mitigating the effects of multipath propagation and Doppler spreading in underwater acoustic communication channels. This paper examines some specifics associated with the design of a multi-channel equalizer for time-varying underwater acoustic channels. More specifically, we study how the number of sensors and separation between them impact the equalization...
In this paper, we address the problem of estimating the two-dimensional (2-D) directions of arrival (DOA) of multiple signals, by means of a sparse L-shaped array. The array consists of one uniform linear array (ULA) and one sparse linear array (SLA). The shift-invariance property of the ULA is used to estimate the elevation angles with low computational burden. The source waveforms are then obtained...
Passive geolocation of a skywave HF source requires accurate estimation of azimuth and elevation angles together with correct ionospheric modeling. Arrays of polarimetric vector sensors have been proposed to reduce the array aperture required for this purpose. However, several factors complicate their application including magneto-ionic raymode splitting resulting in closely-spaced arrivals in both...
In this paper, a beamforming and cell searching method is proposed for a mobile station (MS) with antenna array to compensate the high attenuation in a millimeter wave (mm-wave) OFDM-based cellular systems. A cell searching and direction-of-arrival (DoA) estimation method is proposed for a multipath environment, even with the existence of the symbol timing offsets (STOs) and carrier frequency offsets...
In most research of PN code acquisition performance of antenna array, the signal DOA is regarded as a constant. But in practice, the signal DOA always spreads to a certain extent, which affects PN code acquisition performance. In this paper, the angle extension is introduced into the direct-sequence spread-spectrum array signal model, and PN code acquisition performance is analyzed through CFAR algorithm...
In this paper, we study on DOA estimation error reduction by nested array in the presence of correlated waves. In recent years, at simple array signal processing technique called nested array has been proposed. By using the technique, degrees-of-freedom of the array can be easily increased. However, accuracy of DOA estimation deteriorates when correlated or coherent waves arrived. Therefore, in this...
Accurate estimation of the number of sources plays a crucial role in the source localization and direction-of-arrival estimation problems. In several applications like coastal surveillance and harbour defence, source number estimation has to be performed in a shallow ocean environment. In this paper, the Gerschgorin disk estimator (GDE) method of source number estimation in an unbounded medium is...
In this paper, the capacity of acoustic particle velocity channels is investigated. Closed form expressions are derived that determine maximum data rates in particle velocity channels, in terms of mean angle of arrival and angle spread. These expressions are useful for designing communication systems that operate in particle velocity channels.
The article describes method of S-preparation, which is characterized by high noise immunity and adaptability to uncertainty and variability of the signal-jamming environment, due to the formation of pre-pipelined convolution sums of correlated images.
We present a hidden Markov model based localization using array sensor. In this method, we use the eigenvector spanning signal subspace as a feature for location. The eigenvector does not depend on received signal strength (RSS) but on direction of arrival (DOA) of incident signals. As a result, the eigenvector is robust to fading and noise. In addition, the eigenvector is unique to the environment...
The Minimum Power Distortionless Response (MPDR) beamformer processes the input signal such that the output power is minimized and the signal arriving from a look direction is undistorted. The sample spatial correlation matrix, estimated from snapshots of the received signal, plays a central role in the calculation of MPDR array weights and the estimate of the received signal power from the desired...
Sparse support recovery techniques guarantee successful recovery of sparse solutions to linear underdetermined systems provided the measurement matrix satisfies certain conditions. The maximum level of sparsity that can be recovered with existing algorithms is O(M) where M denotes the size of the measurement vector. This paper shows how this can be improved to O(M2) by assuming certain prior knowledge...
The wide-sense stationary assumption has been frequently employed in array processing, since it results in uncorrelated frequency bins and consequently major simplifications arise. However, unlike stationary signals, significant interfrequency correlations are observable in nonstationary signals like speech. Here, we drop the stationarity assumption and will show that taking interfrequency correlations...
In this work, we present some asymptotic results on the maximum likelihood multi-rank processor for passive wavefront curvature ranging systems using large-scale distributed arrays. We assume that the operation environment for the distributed arrays is subject to a spatial coherence loss. Under an exponential coherence model, analytical expressions for the multi-rank combiners are derived. The results...
Recently we have shown how a blind source extraction (BSE) algorithm can be equipped with some prior information about mixing parameters of the desired source in order to extract this source. The prior information, which may contain errors, is used to construct a matrix from linear combinations of correlation matrices. The extraction filter is easily obtained from the specific eigenstructure of this...
A new method for passive localization using an array sensor system based on spatial smoothing processing (SSP) with support vector machine (SVM) is proposed. The array sensor uses only one array antenna as the receiver to observe the signal subspace spanned by eigenvector through array signal processing. The signal subspace represents the radio wave propagation of interest. Based on the eigenvector,...
Multi-microphone noise reduction methods often operate in the time-frequency domain in which a complex gain is applied to each time-frame and subband. These methods can achieve good noise reduction with little speech distortion by exploiting the fact that the desired signal is correlated across the channels. In the context of single-microphone noise reduction, it has been shown recently that the performance...
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