Wszystkie pola: direction - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Comparative Study between Several Direction of Arrival Estimation Methods
Autorzy:: Khmou, Y.
Safi, S.
Frikel, M.
Powiązania:: https://bibliotekanauki.pl/articles/308017.pdf
Data publikacji:: 2014
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: array processing
Direction of Arrival
geolocalization
propagation
smart antenna
spectral analysis
Opis:: In this paper a comparative study, restricted to one-dimensional stationary case, between several Direction of Arrival (DOA) estimation algorithms of narrowband signals is presented. The informative signals are corrupted by an Additive White Gaussian Noise (AWGN), to show the performance of each method by applying directly the algorithms without pre-processing techniques such as forward-backward averaging or spatial smoothing.
Źródło:: Journal of Telecommunications and Information Technology; 2014, 1; 41-48
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: High-resolution Direction of Arrival Estimation Method Based on Sparse Arrays with Minimum Number of Elements
Autorzy:: Mohammed, Jafar Ramadhan
Powiązania:: https://bibliotekanauki.pl/articles/1839475.pdf
Data publikacji:: 2021
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: compressed sensing
direction of arrival
DOA
estimation
sparse array
Opis:: Regular fully filled antenna arrays have been widely used in direction of arrival (DOA) estimation. However, practical implementation of these arrays is rather complex and their resolutions are limited to the beamwidth of the array pattern. Therefore, higher resolution and simpler methods are desirable. In this paper, the compressed sensing method is first applied to an initial fully filled array to randomly select the most prominent and effective elements which are used to form the sparse array. To keep the dimension of the sparse array equal to that of the fully filled array, the first and the last elements were excluded from the sparseness process. In addition, some constraints on the sparse spectrum are applied to increase estimation accuracy. The optimization problem is then solved iteratively using the iterative reweighted l1 norm. Finally, a simple searching algorithm is used to detect peaks in the spectrum solution that correspond to the directions of the arriving signals. Compared with the existing scanned beam methods, such as the minimum variance distortionless response (MVDR) technique, and with subspace approaches, such as multiple signal classification (MUSIC) and ESPIRT algorithms, the proposed sparse array method offers better performance even with a lower number of array elements and in severely noisy environments. Effectiveness of the proposed sparse array method is verified via computer simulations.
Źródło:: Journal of Telecommunications and Information Technology; 2021, 1; 8-14
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: High-resolution Direction of Arrival Estimation Method Based on Sparse Arrays with Minimum Number of Elements
Autorzy:: Mohammed, Jafar Ramadhan
Powiązania:: https://bibliotekanauki.pl/articles/1839489.pdf
Data publikacji:: 2021
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: compressed sensing
direction of arrival
DOA
estimation
sparse array
Opis:: Regular fully filled antenna arrays have been widely used in direction of arrival (DOA) estimation. However, practical implementation of these arrays is rather complex and their resolutions are limited to the beamwidth of the array pattern. Therefore, higher resolution and simpler methods are desirable. In this paper, the compressed sensing method is first applied to an initial fully filled array to randomly select the most prominent and effective elements which are used to form the sparse array. To keep the dimension of the sparse array equal to that of the fully filled array, the first and the last elements were excluded from the sparseness process. In addition, some constraints on the sparse spectrum are applied to increase estimation accuracy. The optimization problem is then solved iteratively using the iterative reweighted l1 norm. Finally, a simple searching algorithm is used to detect peaks in the spectrum solution that correspond to the directions of the arriving signals. Compared with the existing scanned beam methods, such as the minimum variance distortionless response (MVDR) technique, and with subspace approaches, such as multiple signal classification (MUSIC) and ESPIRT algorithms, the proposed sparse array method offers better performance even with a lower number of array elements and in severely noisy environments. Effectiveness of the proposed sparse array method is verified via computer simulations.
Źródło:: Journal of Telecommunications and Information Technology; 2021, 1; 8-14
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Optimization of Direct Direction Finding Method with Two-Dimensional Correlative Processing of Spatial Signal
Autorzy:: Tsyporenko, V. V.
Tsyporenko, V. G.
Powiązania:: https://bibliotekanauki.pl/articles/307660.pdf
Data publikacji:: 2018
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: antenna array
correlative interferometric
direct method
radio direction finding
Opis:: In this article, the main parameter of the correlative-interferometric direction ﬁnding method with twodimensional correlative processing of spatial signal in the aperture of a linear antenna array (AA) is determined as the value of spatial shift within the AA aperture. The corresponding objective function is also formed. Analytical optimization of this parameter is presented and a comparative analysis of analytical calculations based on simulation results is conducted. In the simulation, a range of dependencies of the middle square deviation of estimation of direction on the value of the spatial shift for a signal-to-noise ratio of 0 dB, for minimum 3-sample and 4-sample Blackman-Harris windows of the spectral analysis, is received. The value of the middle square deviation of estimation of direction will be minimal and will equal 0.02 degrees using a minimum 3-sample Blackman-Harris window with the −67 dB level of side lobes. It oﬀers high noise immunity and high accuracy of direction ﬁnding.
Źródło:: Journal of Telecommunications and Information Technology; 2018, 4; 46-53
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Minimum Array Elements for Resolution of Several Direction of Arrival Estimation Methods in Various Noise-Level Environments
Autorzy:: El Ouargui, I.
Saﬁ, S.
Frikel, M.
Powiązania:: https://bibliotekanauki.pl/articles/956990.pdf
Data publikacji:: 2018
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: covariance matrix
direction of arrival
geolocation
resolution
noise
smart antenna
Opis:: The resolution of a Direction of Arrival (DOA) estimation algorithm is determined based on its capability to resolve two closely spaced signals. In this paper, authors present and discuss the minimum number of array elements needed for the resolution of nearby sources in several DOA estimation methods. In the real world, the informative signals are corrupted by Additive White Gaussian Noise (AWGN). Thus, a higher signal-to-noise ratio (SNR) offers a better resolution. Therefore, we show the performance of each method by applying the algorithms in diﬀerent noise level environments.
Źródło:: Journal of Telecommunications and Information Technology; 2018, 2; 87-94
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: LDAOR - Location and Direction Aware Opportunistic Routing in Vehicular Ad hoc Networks
Autorzy:: Barootkar, M.
Rahbar, A. G.
Sabaei, M.
Powiązania:: https://bibliotekanauki.pl/articles/309175.pdf
Data publikacji:: 2016
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: carry-and-forward mechanism
contact history knowledge
direction and location aware routing
opportunistic routing
vehicular ad hoc networks
Opis:: Routing in Vehicular Ad hoc Networks (VANETs) has found significant attention because of its unique features such as lack of energy constraints and high-speed vehicles applications. Besides, since these networks are highly dynamic, design process of routing algorithms suitable for an urban environment is extremely challenging. Appropriate algorithms could be opportunistic routing (OR) where traffic transmission is performed using the store-carry-forward mechanism. An efficient OR mechanism, called Location and Direction Aware Opportunistic Routing (LDAOR), is proposed in this paper. It is based on the best neighbor node selection by using vehicles positions, vehicles directions, and prioritization of messages from buffers, based on contact histories and positions of neighbor nodes to destination. In LDAOR, when multiple nodes make contact with a carrier node, the closest neighbor node to destination is selected as the best forwarder. However, when only one node makes contact with the carrier node, the message is delivered to it if it moves toward the destination. Using the ONE simulator, the obtained performance evaluation results show that the LDAOR operates better than conventional OR algorithms. The LDAOR not only increases delivery rate, but also reduces network overhead, traffic loss, and number of aborted messages.
Źródło:: Journal of Telecommunications and Information Technology; 2016, 1; 68-83
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: An Improved Greedy Forwarding Scheme in MANETs
Autorzy:: Mishra, P.
Gandhi, C.
Singh, B.
Powiązania:: https://bibliotekanauki.pl/articles/308279.pdf
Data publikacji:: 2017
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: MANET
distance-based routing
direction-based routing
greedy forwarding
Opis:: Position-based routing protocols are widely accepted efficient solution for routing in MANETs. The main feature of position-based routing protocols is to use greedy forwarding methods to route data. The greedy forwarding methods select a node, either having maximum progress towards destination (distance-based principle) or minimum deviation with line between source and destination (direction-based strategy). The first method minimizes the hopcount in a path and on the other hand, second method minimizes the spatial distance between source and destination. The distance-based routing has a great impact on the selection of reliable node and the direction based routing plays a major role to increase the stability of route towards destination. Therefore, in this paper authors propose a weighted forwarding method, which combines both the selection, schemes to select an optimal next forwarding node in a range. The simulation results show that the proposed scheme performs better than existing position-based routing protocols.
Źródło:: Journal of Telecommunications and Information Technology; 2017, 1; 50-55
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Lorentzian Operator for Angular Source Localization with Large Array
Autorzy:: Khmou, Y.
Safi, S.
Frikel, M.
Powiązania:: https://bibliotekanauki.pl/articles/308330.pdf
Data publikacji:: 2015
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: array processing
Direction of Arrival
narrowband
operator
Opis:: Source localization problem consists of an ensemble of techniques that are used to obtain spatial information of present radiation in given medium of propagation, with a constraint of the antenna geometry and the characteristics of radiating sources. This condition gives multitude of cases to study, hence several methods were proposed in the literature. In this paper, a new algorithm for estimating the Direction of Arrival (DoA) of narrowband and far eld punctual sources is introduced. By exploiting the spectrum of covariance matrix of received data, the Lorentzian function on spectral matrix to lter the eigenvalues is applied. This ltering process eliminates the eigenvalues belonging to signal subspace. Parameters of Lorentz function are adjusted using rst and second statistics of eigenvalues. The algorithm requires the knowledge of minimum eigenvalue and is performing when the dimension of antenna is relatively large which is conrmed by several Monte Carlo simulations.
Źródło:: Journal of Telecommunications and Information Technology; 2015, 4; 98-105
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: A wideband smart antenna employing spatial signal processing
Autorzy:: Uthansakul, M.
Białkowski, M. E.
Powiązania:: https://bibliotekanauki.pl/articles/307580.pdf
Data publikacji:: 2007
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: direction estimation
null steering
wideband beamforming
wideband smart antenna
wideband antenna
Opis:: A smart antenna with capability of beam steering in azimuth over a wide frequency band using only spatial signal processing is presented. Filters and tapped-delay networks employed in conventional wideband linear arrays are avoided by using a two-dimensional rectangular array structure. In this array, only constant real-valued weighting coefficients, realized with amplifiers or attenuators, are used to form a desired radiation pattern. In order to estimate direction of arrival of a wideband signal, the MUSIC algorithm in conjunction with an interpolated array technique is applied. In the interpolated array technique, a composite covariance matrix is generated, which is a simple addition of covariance matrices of narrowband virtual arrays, being stretched or compressed versions of a nominal array. A working prototype of this wideband array is presented. Its operation is assessed via full EM simulations and measurements.
Źródło:: Journal of Telecommunications and Information Technology; 2007, 1; 13-17
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: SPOT-GPR: A Freeware Toolfor Target Detection and Localizationin GPR Data Developedwithin the COST Action TU1208
Autorzy:: Meschino, S.
Pajewski, L.
Powiązania:: https://bibliotekanauki.pl/articles/308799.pdf
Data publikacji:: 2017
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: Direction-of-Arrival algorithms
Ground-Penetrating Radar
matched ﬁlter technique
MUltiple SIgnal Classiﬁcation (MUSIC)
Sub-Array Processing
Opis:: SPOT-GPR (release 1.0) is a new freeware tool implementing an innovative Sub-Array Processing method, for the analysis of Ground-Penetrating Radar (GPR) data with the main purposes of detecting and localizing targets. The software is implemented in Matlab, it has a graphical user interface and a short manual. This work is the outcome of a series of three Short-Term Scientific Missions (STSMs) funded by European COoperation in Science and Technology (COST) and carried out in the framework of the COST Action TU1208 “Civil Engineering Applications of Ground Penetrating Radar” (www.GPRadar.eu). The input of the software is a GPR radargram (B-scan). The radargram is partitioned in subradargrams, composed of a few traces (A-scans) each. The multi-frequency information enclosed in each trace is exploited and a set of dominant Directions of Arrival (DoA) of the electromagnetic field is calculated for each sub-radargram. The estimated angles are triangulated, obtaining a pattern of crossings that are condensed around target locations. Such pattern is filtered, in order to remove a noisy background of unwanted crossings, and is then processed by applying a statistical procedure. Finally, the targets are detected and their positions are predicted. For DoA estimation, the MUltiple SIgnal Classification (MUSIC) algorithm is employed, in combination with the matched filter technique. To the best of our knowledge, this is the first time the matched filter technique is used for the processing of GPR data. The software has been tested on GPR synthetic radargrams, calculated by using the finite-difference time-domain simulator gprMax, with very good results.
Źródło:: Journal of Telecommunications and Information Technology; 2017, 3; 43-54
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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