A Novel Sparse Array for Localization of Mixed Near-Field and Far-Field Sources

As we all know, nested array can obtain a larger array aperture and more degrees of freedom using fewer sensors. In this study, we not only designed an enhanced symmetric nested array (ESNA), which achieved more consecutive lags and more unique lags compared with a generalized nested array but also developed a special cumulant matrix, in the case of a given number of sensors, which can automatically generate the largest consecutive lags of the array. First, the direction-of-arrivals (DOAs) of mixed sources are estimated using the special cumulant matrix. Then, we can estimate the range of the near-field source in the mixed source using a one-dimensional spectral search through estimated DOAs, and in the mixed sources, the near-field and far-field sources are classified by bringing in the range parameter. The largest consecutive lags and composition method of ESNA are also given, under a given number of sensors.Our algorithm has moderate computation complexity, which provides a higher resolution and improves the parameters’ estimation accuracy. Numerical simulation results demonstrate that the proposed array showed an outstanding performance under estimation accuracy and resolution ability for both DOA and range estimation compared with existing arrays of the same physical array sensors.

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Mixed Far-Field and Near-Field Source Localization Algorithm via Sparse Subarrays

International Journal of Antennas and Propagation ◽

10.1155/2018/3237167 ◽

2018 ◽

Vol 2018 ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

Jiaqi Song ◽

Haihong Tao ◽

Jian Xie ◽

Chenwei Sun

Keyword(s):

Near Field ◽

Doa Estimation ◽

Estimation Accuracy ◽

Far Field ◽

Localization Algorithm ◽

Range Estimation ◽

Field Source ◽

Quarter Wavelength ◽

Shift Invariance ◽

Array Aperture

Based on a dual-size shift invariance sparse linear array, this paper presents a novel algorithm for the localization of mixed far-field and near-field sources. First, by constructing a cumulant matrix with only direction-of-arrival (DOA) information, the proposed algorithm decouples the DOA estimation from the range estimation. The cumulant-domain quarter-wavelength invariance yields unambiguous estimates of DOAs, which are then used as coarse references to disambiguate the phase ambiguities in fine estimates induced from the larger spatial invariance. Then, based on the estimated DOAs, another cumulant matrix is derived and decoupled to generate unambiguous and cyclically ambiguous estimates of range parameter. According to the coarse range estimation, the types of sources can be identified and the unambiguous fine range estimates of NF sources are obtained after disambiguation. Compared with some existing algorithms, the proposed algorithm enjoys extended array aperture and higher estimation accuracy. Simulation results are given to validate the performance of the proposed algorithm.

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Hybrid multilevel plane wave based near-field far-field transformation utilising combined near- and far-field translations

Advances in Radio Science ◽

10.5194/ars-7-17-2009 ◽

2009 ◽

Vol 7 ◽

pp. 17-22 ◽

Cited By ~ 1

Author(s):

C. H. Schmidt ◽

T. F. Eibert

Keyword(s):

Near Field ◽

Measurement Techniques ◽

Plane Waves ◽

Low Complexity ◽

Far Field ◽

Computation Complexity ◽

Low Frequencies ◽

Field Transformation ◽

Translation Operators ◽

Equivalent Sources

Abstract. The radiation of large antennas and those operating at low frequencies can be determined efficiently by near-field measurement techniques and a subsequent near-field far-field transformation. Various approaches and algorithms have been researched but for electrically large antennas and irregular measurement contours advanced algorithms with low computation complexity are required. In this paper an algorithm employing plane waves as equivalent sources and utilising efficient diagonal translation operators is presented. The efficiency is further enhanced using simple far-field translations in combination with the expensive near-field translations. In this way a low complexity near-field transformation is achieved, which works for arbitrary sample point distributions and incorporates a full probe correction without increasing the complexity.

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Mixed near-field and far-field source localization utilizing symmetric nested array

Digital Signal Processing ◽

10.1016/j.dsp.2017.10.021 ◽

2018 ◽

Vol 73 ◽

pp. 16-23 ◽

Cited By ~ 15

Author(s):

Ye Tian ◽

Qiusheng Lian ◽

He Xu

Keyword(s):

Source Localization ◽

Near Field ◽

Far Field ◽

Field Source

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RADIATED ACOUSTIC PRESSURE FROM A MOVING, NONUNIFORMLY VIBRATING CYLINDER WITH TWO SPHERICAL ENDCAPS

Journal of Computational Acoustics ◽

10.1142/s0218396x94000063 ◽

1994 ◽

Vol 02 (01) ◽

pp. 71-82 ◽

Cited By ~ 1

Author(s):

ZHAOXI WANG ◽

SEAN F. WU

Keyword(s):

Near Field ◽

Translational Motion ◽

Normal Component ◽

Forward Direction ◽

Numerical Results ◽

Surface Velocity ◽

Reverse Direction ◽

Far Field ◽

Field Source ◽

Sound Diffraction

This paper presents numerical results of radiated acoustic pressures from a moving, nonuniformly vibrating cylinder with two spherical endcaps, based on an extended Kirchhoff integral formulation. Specifically, we consider cases in which the normal component of the surface velocity is nonzero on a portion of the surface, and zero elsewhere. Numerical results demonstrate that the radiation patterns depend critically on the frequency and source dimensions. For a noncompact source, the strongest radiation may not necessarily stem from a vibrating surface, but rather from a nonvibrating surface due to the effect of sound diffraction. The more noncompact the source is, the larger the number of side lobes in the near field and the more concentrated these side lobes will be. In the far field, however, the side lobes become smeared and less distinguishable. In other words, the effect of sound diffraction is greatly reduced in the far field. Source translational motion induces sound radiation in the perpendicular direction and enhances the radiated acoustic field in general. Enhancement in the forward direction is much greater than in the reverse direction.

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Mixed Far-Field and Near-Field Source Localization Using a Linear Electromagnetic-Vector-Sensor Array with Gain/Phase Uncertainties

IEEE Access ◽

10.1109/access.2020.2981483 ◽

2020 ◽

pp. 1-1

Author(s):

Huihui Ma ◽

Haihong Tao ◽

Hailong Kang

Keyword(s):

Source Localization ◽

Sensor Array ◽

Near Field ◽

Far Field ◽

Field Source ◽

Vector Sensor ◽

Electromagnetic Vector Sensor ◽

Vector Sensor Array

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An Efficient Near-Field Localization Method of Coherently Distributed Strictly Non-circular Signals

Sensors ◽

10.3390/s20185176 ◽

2020 ◽

Vol 20 (18) ◽

pp. 5176

Author(s):

Meidong Kuang ◽

Ling Wang ◽

Yuexian Wang ◽

Jian Xie

Keyword(s):

Near Field ◽

Integral Form ◽

Approximate Expression ◽

Probability Density Functions ◽

Estimation Accuracy ◽

Density Functions ◽

Classical Probability ◽

One Dimensional ◽

Spatially Distributed ◽

Field Localization

For the near-field localization of non-circular distributed signals with spacial probability density functions (PDF), a novel algorithm is proposed in this paper. The traditional algorithms dealing with the distributed source are only for the far-field sources, and they need two-dimensional (2D) search or omit the angular spread parameter. As a result, these algorithms are no longer inapplicable for near-filed localization. Hence the near-filed sources that obey a classical probability distribution are studied and the corresponding specific expressions are given, providing merits for the near-field signal localization. Additionally, non-circularity of the incident signal is taken into account in order to improve the estimation accuracy. For the steering vector of spatially distributed signals, we first give an approximate expression in a non-integral form, and it provides the possibility of separating the parameters to be estimated from the spatially discrete parameters of the signal. Next, based on the rank-reduced (RARE) algorithm, direction of arrival (DOA) and range can be obtained through two one-dimensional (1-D) searches separately, and thus the computational complexity of the proposed algorithm is reduced significantly, and improvements to estimation accuracy and identifiability are achieved, compared with other existing algorithms. Finally, the effectiveness of the algorithm is verified by simulation.

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Near-field source localization of quasi-stationary signals with increased degrees of freedom

2020 28th European Signal Processing Conference (EUSIPCO) ◽

10.23919/eusipco47968.2020.9287455 ◽

2021 ◽

Author(s):

Jingjing Pan ◽

Meng Sun ◽

Yide Wang ◽

Xiaofei Zhang

Keyword(s):

Source Localization ◽

Degrees Of Freedom ◽

Near Field ◽

Field Source ◽

Stationary Signals

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Tensor CSAMT survey over the Sulphur Springs thermal area, Valles Caldera, New Mexico, United States of America, Part II: Implications for CSAMT methodology

Geophysics ◽

10.1190/1.1444157 ◽

1997 ◽

Vol 62 (2) ◽

pp. 466-476 ◽

Cited By ~ 41

Author(s):

Philip E. Wannamaker

Keyword(s):

Near Field ◽

Skin Depth ◽

Small Scale ◽

Far Field ◽

Survey Area ◽

Wave Regime ◽

Low Frequencies ◽

Field Source ◽

Source Field ◽

Sulphur Springs

The resistivity model for the Sulphur Springs area in the companion paper (Part I) plus the availability of overlapping controlled‐source audiomagnetotelluric (CSAMT) and magnetotelluric (MT) data has allowed study of far‐field to near‐field transitions, source field geometries over the survey area, and scalar‐tensor impedance discrepancies. The regional setting of conductive Paleozoic sediments over resistive basement seriously reduced depth of exploration within the plane‐wave regime to about 1/20th of the transmitter‐receiver separation, rather than the traditional 1/3rd to 1/5th based on half‐space models. As frequency falls to where skin depth in the sedimentary layer exceeds its thickness, transmitter electromagnetic (EM) fields enter the resistive basement and may diffuse to the receiver with relatively little attenuation, promoting near‐field behavior. Comparisons are made of observed electric (E) and magnetic (H) fields inside and outside the caldera with EM fields computed from layered resistivity models derived from local 1-D inversion of the ρa and θ, and from simple 3-D models. First, the comparisons indicate that small‐scale structure near the transmitter does not lead to overprint effects in the impedance data at the receiver but, instead, acts as an equivalent far‐field source. Second, at both high and low frequencies, the observed E and H fields can depart substantially from those predicted by local layered models. In fact, an effective regional layering appears to control the magnetic field amplitudes and the far‐to near‐field transition in this survey area. The observed electric fields, on the other hand, are controlled by all scales of geology. When heterogeneity is important, significant departures between scalar and tensor CSAMT data can be expected, and are exacerbated when the source field is poorly coupled to the sensors. The problem is much reduced for vector CSAMT measurements where all horizontal field components are measured and the maximally coupled results are defined, but mode identification is more difficult for multidimensional structures.

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