scholarly journals Deteksi Radar Terhadap Multi-Object Bergerak Dengan Pemrosesan Doppler

2021 ◽  
Vol 1 ◽  
pp. 17-26
Author(s):  
Reyhan Fahmirakhman Abdullah ◽  
Dharu Arseno ◽  
Fiky Yosef Suratman
Keyword(s):  
Electromagnetic Wave ◽  
Radio Wave ◽  
Matched Filter ◽  
Directional Antenna ◽  
Wave System ◽  
Narrow Beam ◽  
Moving Targets ◽  
Short Radio Wave ◽  
Radio Detection ◽  
Wave Emission

In general, Radar or Radio Detection and Ranging is an electromagnetic wave system that is useful to measure distance and answer and make maps of surrounding objects. Radar has an advantage compared to other navigation tools, which is that radar does not require a transmitter station as a transmitter. Radar has an electronic wave emission principle that emits short radio wave pulses emitted in a narrow beam by a directional antenna. In this study, a multi-object radar detection simulation was carried out using Dopler processing both MTI and PDP, which later on the radar will detect related objects. Multi-object here is a condition that is achieved when a navigation radar detects more than one object. The result of this research is a multi-object detection process using the MTI and PDP methods and the matched-filter obtained from the predetermined data. So Doppler processing aims to mitigate the clutter signal to improve the detection performance of moving targets even though there is a dominance of signals originating from stationary clutter. 

Kinetic theory of the interaction in an electron current-electromagnetic wave system

1982 ◽  
Vol 25 (4) ◽  
pp. 305-308
Author(s):  
B. N. Bondarenko ◽  
Yu. A. Dimashko ◽  
V. G. Kryzhanovskii
Keyword(s):  
Electromagnetic Wave ◽  
Kinetic Theory ◽  
Wave System ◽  
Electron Current

Контроль электрофизических параметров метаматериалов методом поверхностных электромагнитных волн

2021 ◽  
pp. 51-67
Author(s):  
А.И. Казьмин ◽  
П.А. Федюнин
Keyword(s):  
Inverse Problem ◽  
Electromagnetic Wave ◽  
Radio Wave ◽  
Local Control ◽  
Negative Refraction ◽  
Test Sample ◽  
Experimental Investigations ◽  
Surface Electromagnetic Wave ◽  
New Radio ◽  
Electrophysical Parameters

Development of metamaterials has led to the search and choice of effective methods of radio-wave nondestructive testing of their electrophysical parameters. The existing approaches to testing based on extracted of effective electrophysical parameters of metamaterials from the coefficients of reflection and transmission of an electromagnetic wave have low reliability and don't provide their local control. We present the new radio-wave method of local control of complex dielectric permittivity and magnetic permeability, as well as the thickness of metamaterial plate on a metal substrate with surface microwaves. The method is based on the solution of inverse problem in the determination of effective electrophysical parameters of metamaterial from the frequency dependence of the attenuation coefficient of the field of a slow surface electromagnetic wave excited in a test sample. The electrophysical parameters of the metamaterial are represented as parametric frequency functions in accordance with the Drude-Lorentz models of dispersion, and the solution of the inverse problem is reduced to minimizing the objective function constructed based on the discrepancy between the experimental and design theoretical values of the attenuation coefficients of surface electromagnetic wave fields on a grid of discrete frequencies. The structure of a measuring complex that implements the proposed method of control is proposed. For the numerical and experimental verification of the method, a sample of a metamaterial plate based on SRR elements with a negative refraction region in the frequency band 10.06–10.64 GHz was investigated. Experimental investigations of the metamaterial demonstrated the theoretical capabilities gained with measurement of the local electrophysical parameters with relative error not greater 10 %.

scholarly journals Measuring the eccentricity of GW170817 and GW190425

2020 ◽  
Vol 497 (2) ◽  
pp. 1966-1971 ◽  
Author(s):  
Amber K Lenon ◽  
Alexander H Nitz ◽  
Duncan A Brown
Keyword(s):  
Parameter Estimation ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Matched Filter ◽  
Wave Frequency ◽  
Limited Information ◽  
Binary Neutron Star ◽  
Wave Emission

ABSTRACT Two binary neutron star mergers, GW170817 and GW190425, have been detected by Advanced LIGO and Virgo. These signals were detected by matched-filter searches that assume that the star’s orbit has circularized by the time their gravitational-wave emission is observable. This suggests that their eccentricity is low, but full parameter estimation of their eccentricity has not yet been performed. We use gravitational-wave observations to measure the eccentricity of GW170817 and GW190425. We find that the eccentricity at a gravitational-wave frequency of 10 Hz is e ≤ 0.024 and e ≤ 0.048 for GW170817 and GW190425, respectively (90 per cent confidence). This is consistent with the binaries being formed in the field, as such systems are expected to have circularized to e ≤ 10−4 by the time they reach the LIGO–Virgo band. Our constraint is a factor of 2 smaller that an estimate based on GW170817 being detected by searches that neglect eccentricity. However, we caution that we find significant prior dependence in our limits, suggesting that there is limited information in the signals. We note that other techniques used to constrain binary neutron star eccentricity without full parameter estimation may miss degeneracies in the waveform, and that for future signals, it will be important to perform full parameter estimation with accurate waveform templates.

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