Discrimination of the Target and Chaff in
Multi-dimensional Space
Nadali
Zareei
Imam Hosein university
author
Mohammad Mahdi
Nayebi
صنعتی شریف
author
Ahmad Reza
Amin
جامع امام حسین (ع)
author
Meysam
Rayisdanayi
Imam Hosein university
author
Habibalah
Alami
جامع امام حسین (ع)
author
text
article
2018
per
Abstract: Among the various techniques of electronic warfare in the sea, Chaff is very particular due to its easy application, low-cost manufacturing and its impact on the victim radar. Despite the fact that the use of Chaff is dated back to the 1940s, the significant research has not been published on its recognition. It is difficult to study the behavior of Chaff because of the impossibility of Chaff tests in an unechoic chamber. Therefore, the simulation would be a suitable alternative for the study of its behavior. In this paper, the simulation of various features of the target and Chaff are presented in a multi-dimensional space whose features are dependent together. This multi-dimensional space is used to propose a processing structure, based on train and test of the various classifiers, for discrimination between Chaff and the target. Moreover, the comparison between discrimination capability of various classifiers using simulated and real data is carried out and the suitable classifier is concluded for sea applications.
Radar
Imam Hussein University
2345-4024
5
v.
4
no.
2018
1
10
https://radar.ihu.ac.ir/article_202728_9d1a4fab18607a49b040a095546a9337.pdf
Parameters Estimation and Imaging of Ground Moving
Target in a One-stationary Bi-static SAR
Seyed Mohammad
Zabihi Maddah
فردوسی مشهد
author
Seyed Alireza
Seyedin
دانشیار، گروه مهندسی برق، دانشکده مهندسی، دانشگاه فردوسی مشهد
author
text
article
2018
per
In this paper, the equation of the received signal of a moving target with constant acceleration in a special case of Bi-static SAR, named one-stationary, is derived in a slant range plane. In the one-stationary geometry, usually range curvature and Doppler ambiguity is very large due to wide beam-width and assumption of accelerating movement of the target. Hence, transforms such as Radon and Keystone have little accuracy for both estimating Doppler centroid and removing range cell migration. In this paper, a two-step algorithm is proposed for estimation of Doppler centroid. That is a combination of radon transform and a search algorithm. Then, by extraction of a system of equations, an estimation of target’s velocity and acceleration is obtained and finally, an image formation algorithm is presented. Compared to usual algorithms, the accuracy of the derived equations and the strength of the proposed algorithm in the presence of noise and clutter are confirmed by simulations.
Radar
Imam Hussein University
2345-4024
5
v.
4
no.
2018
11
24
https://radar.ihu.ac.ir/article_202729_bca500dc9bd69d35c5b1a85fd73f925b.pdf
The Effect of Parabolic Cathode Shaping on Relativistic
Magnetron Performance
Hassan
Zibaeinejad
دانشگاه شیراز
author
Habibollah
Abiri
دانشگاه شیراز
author
text
article
2018
per
In this paper, it is demonstrated that shaping of the cathode along the symmetry axis in a relativistic magnetron, leads to a shift in Hull and Hartree curves in such a way that a set of curves is obtained instead of only two curves. This results in excitation of numerous harmonics and proposing a broadband tube. As an example, without any changes in the anode structure, A6 relativistic magnetron cathode has been subjected to parabolic shaping parallel to the symmetry axis preserving the axial symmetry. To perform a study with this regard, employing a 3D particle in cell simulation, it has been shown that the output power can exceed 400MW while the frequency ranges from 5GHz to 20 GHz.
Radar
Imam Hussein University
2345-4024
5
v.
4
no.
2018
25
32
https://radar.ihu.ac.ir/article_202730_3942b5310130c2ed3f1e02e645dd052c.pdf
Investigation of Performance Changes of Leaky Wave
Antennas in the Aerodynamic Heating Phenomenon of
Hypersonic Projectiles
Shahriar
Tavanaei pour
دانشگاه تهران
author
Mohammad Ali
Joz Vaziri
دانشگاه جامع امام حسین(ع)
author
text
article
2018
per
In this study, the effect of aerodynamic heating has been investigated on the performance of leaky wave antennas in hypersonic projectiles. For this purpose, first the projectile’s surface temperature is obtained using aerodynamic simulations. Then, with thermal simulation of the leaky wave antenna designed in the X frequency band, its temperature is calculated with the assumption that the upper surface of the antenna lies on the exterior surface of the projectile. The next step is to investigate the changes in antenna’s performance by studying the changes in its shape and the properties of its materials. The most significant change in the performance is observed for the S11 parameter, which has a frequency shift of around 140 MHz at 1880 Kelvin. Finally, changes of the main beam direction as well as the level of the first sidelobe have been studied with respect to temperature changes
Radar
Imam Hussein University
2345-4024
5
v.
4
no.
2018
33
38
https://radar.ihu.ac.ir/article_202731_ae2e12e657dad6186ce182edc72e94f2.pdf
Design and Construction of 100W Solid State Pulse
Amplifier by using CW Amplifier Modules
Alireza
Rezaei
دانشگاه تهران
author
Taher
Cheraghi
دانشگاه تهران
author
text
article
2018
per
This article describes the basics of designing and constructing a power amplifier at 4.3GHz. This power amplifier consists of three 60W modules and switches between two pulse modes and CW (manually or through the control interface). The components of this amplifier include a power divider, a power combiner and an isolator and they are fully designed. This amplifier is used in telecommunication transmitter. For the design of the 100 watt power amplifier, combination of the Toshiba TIM4450-60SL transistor has been used. Also, a similar transistor is used as a pre-amplifier in the power input of the combiner connector. In order to simulate the bias gate, the power combiner and microstrip power divider circuit are simulated in the AWR software. A Simple design, native technology and the ease of construction are the main features of this design. An isolator is used at the input and output of the amplifier. Therefore, if the amplifier input remains open for any reasons or the input cable is not properly closed, the amplifier will not fluctuate.
Radar
Imam Hussein University
2345-4024
5
v.
4
no.
2018
39
48
https://radar.ihu.ac.ir/article_202732_55bafc680b2680da8c2cbf8fd738cce2.pdf
SNR Improvement in Semi-active Tracking Radar Using
Signal Parameters Estimation
Kazem
Heydari
تربیت مدرس
author
Paeiz
Azmi
دانشگاه تربیت مدرس
author
Bijan
Abbasi Arand
دانشگاه تربیت مدرس
author
text
article
2018
per
In continuous wave (CW) radar systems, the efficiency of semi-active chaser receiver in the tracking of target is of paramount importance. In a situation where the target and chaser have variable speed (accelerated motion) relative to one another, in the semi-active chaser receiver, the received signal has time varying Doppler frequency shifts. In this paper, semi-active receiver with hierarchical features first acquires an estimation of the parameters of the received signal using the short time-frequency transform (STFT) at the time of the acceleration of the target or chaser. Then, mono-pulse angular tracking accuracy is tested using a matched filter based on the estimated parameters of the received signal. Eventually, providing the required simulation, the proposed method is compared with “maximum signal spectrum” and “average signal spectrum” methods. The results imply that the matched filter-based algorithm has a better performance than other algorithms.
Radar
Imam Hussein University
2345-4024
5
v.
4
no.
2018
49
60
https://radar.ihu.ac.ir/article_202733_a985341e09035d0e0977686792181450.pdf