scholarly journals Interval and Point Direction Finding of Radio Emission Sources for Broadband Radio Monitoring

2020 ◽  
Vol 23 (6) ◽  
pp. 28-42
Author(s):  
M. E. Shevchenko ◽  
V. N. Malyshev ◽  
S. S. Sokolov ◽  
A. V. Gorovoy ◽  
S. N. Soloviev ◽  
...  
Keyword(s):  
Antenna Array ◽  
Elevation Angle ◽  
Direction Finding ◽  
Radio Monitoring ◽  
Point Estimates ◽  
Broadband Radio ◽  
Narrow Frequency Band ◽  
Signal Mode ◽  
Sample Interval ◽  
The Time Domain

Introduction. The point and interval direction finding of radio sources is used for broadband radio monitoring in the frequency domain. The initial data for broadband radio monitoring are spectral samples obtained from an M-element antenna array by multichannel reception. Point direction finding is based on a grouping of point estimates of azimuth and elevation angle formed for each frequency sample, in which signal components are detected. A single estimate of azimuth and elevation angle is made based on the grouped point estimates in the range of neighbouring frequency samples. Interval direction finding is based on the azimuth and elevation estimates formed entirely from the interval of adjacent frequency samples, in which the signal components are found, and the subsequent refinement of frequency sample interval boundaries for each radio source in multisignal mode by spatial selection methods. Point direction finding is mainly implemented in single-signal mode in modern operating broadband radio monitoring complexes, while the multi-signal mode based on MUSIC or ESPRIT is implemented in the time domain in a narrow frequency band.Aim. Development and investigation of methods for point and interval direction finding in multi-signal mode, as well as development of recommendations for their practical application in multi-signal and single-signal modes.Methods. Multi-signal mode for point and interval direction finding was implemented using MUSIC and ESPRIT. An experimental study of the developed direction finding methods in single-signal and multi-signal (on ESPRIT) modes with overlapping signal spectra was carried out by processing the recorded real signals. The records were made using a seven-channel coherent synchronous receiver connected to a seven-element 60° angle antenna array.Results. The research results are presented by frequency-azimuth panoramas and estimates of the amplitude spectra of separated signals and direction finding accuracy indicators.Conclusion. It was experimentally demonstrated that point direction finding should be used in single-signal mode provided the absence of information on the number of signals in the observed data. Interval direction finding is recom-mended in multi-signal mode for improving the accuracy and real-time feasibility of the process.

scholarly journals RADIO SOURCE DIRECTION FINDING IN WIDE FREQUENCY BAND USING CIRCULAR ANTENNA ARRAY

2019 ◽  
pp. 30-40 ◽  
Author(s):  
Maya E. Shevchenko ◽  
Victor N. Malyshev ◽  
Dilara N. Fayzullina
Keyword(s):  
Antenna Array ◽  
Frequency Band ◽  
Elevation Angle ◽  
Field Studies ◽  
Direction Finding ◽  
Statistical Simulation ◽  
Wide Frequency Band ◽  
Direction Finder ◽  
Music Methods ◽  
Radio Systems

For the VHF broadband direction finder, coherent and incoherent direction finding algorithms for switched and non-switched connection of the antenna array (AR) to receiving device in single-signal and multi-signal direction finding modes are developed and investigated.Their synthesis is based on the methods of space-time theory of radio systems. Numerical calculation of the direction finding characteristics of the algorithms for different number of antenna array elements determines the operating range upper limiting frequency, in which this configuration provides single-value estimates of the azimuth and elevation angle. Statistical simulation modeling shows that for an odd number of antennas, the antenna array amplitudephase response is unique in a wider frequency band than for an even number of antennas. Due to this MUSIC based property applied in the space of antenna array elements, direction finding algorithm is developed for wide frequency band with several signals overlapping in frequency, with switched and non-switched AR connection to a radio receiver. It is shown that the use of ESPRIT and MUSIC methods in free-space diagram does not allow for direction finding in a wide frequency band with the antenna array fixed configuration. The results of the field studies of the developed algorithms are presented for the single-signal and multi-signal modes of operation, software and hardware implemented in the VHF radio direction finder. A comparative analysis of the developed algorithms with the known APs with fixed configuration is performed. It is shown that with the same AR configuration, it is the direction finding algorithm that determines the frequency range in which the direction finding is unique.

scholarly journals Antenna system with omnidirectional radiation pattern for systems with phase algorithms of direction finding

2019 ◽  
Vol 30 ◽  
pp. 05021
Author(s):  
Alexander Zhuravlev ◽  
Alexander Golovkov ◽  
Polina Terenteva ◽  
Victor Malyshev ◽  
Michail Shmyrin ◽  
...  
Keyword(s):  
Radiation Pattern ◽  
Communication Systems ◽  
Elevation Angle ◽  
Experimental Studies ◽  
Antenna System ◽  
Monitoring Systems ◽  
Digital Television ◽  
Horizontal Polarization ◽  
Radio Monitoring ◽  
Radiating Element

Ommidirectional in azimuth plane antennas with horizontal polarization are used in communication systems of McWILL standard, digital television systems of DVB-T2 standard, radio monitoring systems, semi-active ranging using the target illumination with the television broadcast signal, and many other cases. In many cases, radar and radio monitoring systems use phase methods to determine the azimuth and elevation angle of the target. To view all azimuthal angles, ring arrays consisting of omnidirectional emitters, usually also represented by ring arrays, are used. This paper studies the characteristics of an omnidirectional radiating element of electrically small horizontal dipole elements. An expression is derived that relates the radius of the dipole ring array to the number of dipoles and the variation of the resulting radiation pattern. The results are confirmed by experimental studies.

Wideband direction-finding based on time-modulated antenna array

2015 ◽  
Author(s):  
Jingfeng Chen ◽  
Ronghong Jin ◽  
Haijun Fan ◽  
Junping Geng ◽  
Xianling Liang ◽  
...  
Keyword(s):  
Antenna Array ◽  
Direction Finding

scholarly journals An Effective Technique for Enhancing Direction Finding Performance of Virtual Arrays

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Wenxing Li ◽  
Xiaojun Mao ◽  
Wenhua Yu ◽  
Chongyi Yue
Keyword(s):  
Antenna Array ◽  
Interpolation Method ◽  
Doa Estimation ◽  
Direction Finding ◽  
Estimation Accuracy ◽  
Signal Subspace ◽  
Effective Technique ◽  
Resolution Capability ◽  
Significant Bias ◽  
Virtual Array

The array interpolation technology that is used to establish a virtual array from a real antenna array is widely used in direction finding. The traditional interpolation transformation technology causes significant bias in the directional-of-arrival (DOA) estimation due to its transform errors. In this paper, we proposed a modified interpolation method that significantly reduces bias in the DOA estimation of a virtual antenna array and improves the resolution capability. Using the projection concept, this paper projects the transformation matrix into the real array data covariance matrix; the operation not only enhances the signal subspace but also improves the orthogonality between the signal and noise subspace. Numerical results demonstrate the effectiveness of the proposed method. The proposed method can achieve better DOA estimation accuracy of virtual arrays and has a high resolution performance compared to the traditional interpolation method.

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