List of Articles Clutter

• Open Access Article
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  1 - The Separation of Radar Clutters using Multi-Layer Perceptron
  Mohammad Akhondi Darzikolaei Ataollah Ebrahimzadeh Elahe Gholami
  10.7508/jist.2017.17.006
  Clutter usually has negative influence on the detection performance of radars. So, the recognition of clutters is crucial to detect targets and the role of clutters in detection cannot be ignored. The design of radar detectors and clutter classifiers are really complica More

  Clutter usually has negative influence on the detection performance of radars. So, the recognition of clutters is crucial to detect targets and the role of clutters in detection cannot be ignored. The design of radar detectors and clutter classifiers are really complicated issues. Therefore, in this paper aims to classify radar clutters. The novel proposed MLP-based classifier for separating radar clutters is introduced. This classifier is designed with different hidden layers and five training algorithms. These training algorithms consist of Levenberg-Marquardt, conjugate gradient, resilient back-propagation, BFGS and one step secant algorithms. Statistical distributions are established models which widely used in the performance calculations of radar clutters. Hence In this research, Rayleigh, Log normal, Weibull and K-distribution clutters are utilized as input data. Then Burg’s reflection coefficients, skewness and kurtosis are three features which applied to extract the best characteristics of input data. In the next step, the proposed classifier is tested in different conditions and the results represent that the proposed MLP-based classifier is very successful and can distinguish clutters with high accuracy. Comparing the results of proposed technique and RBF-based classifier show that proposed method is more efficient. The results of simulations prove that the validity of MLP-based method. Manuscript profile
• Open Access Article
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  2 - Detection of Coherent Radar Signals with Unknown Doppler Shift in Non-Gaussian Clutter
  M. R. Taban A. mohammadi M. Modarres Hashemi
  In this paper the problem of detection of coherent radar signals with slow fluctuating amplitude and unknown Doppler shift in non-Gaussian clutter is considered. Coherent radar signal detection with unknown Doppler shift is rarely considered in the literature. It has be More

  In this paper the problem of detection of coherent radar signals with slow fluctuating amplitude and unknown Doppler shift in non-Gaussian clutter is considered. Coherent radar signal detection with unknown Doppler shift is rarely considered in the literature. It has been demonstrated that in high resolution radars or in small grazing angles, the pseudo-Gaussian models are more accurate than Gaussian for clutter modeling. Optimum detection of signals with unknown Doppler shift in pseudo-Gaussian clutter contains a complicated multiple integral. Therefore, in this paper, generalized forms of the suboptimum GLR and CGLR detectors are proposed. Also, by estimating the random variable related to the clutter power (τ) in the test cell, GLRTLQ detector for unknown Doppler shift case is introduced and generalized. It is demonstrated that the proposed GLRTLQ detector has a simple structure and does not depend on the clutter distribution. The performances of the proposed detectors are evaluated by computer simulation. Manuscript profile
• Open Access Article
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  3 - Radar Detection in Gaussian Clutter Using Bayesian Estimation of Target
  M. F. Sabahi M. Modarres Hashemi a. sheikhi
  In many of detection problems the received signals models under two hypotheses, H0 and H1, are the same except that some model parameters have fixed value under H0. These models are so called Nested Models. One of the most important examples is detection of a target wit More

  In many of detection problems the received signals models under two hypotheses, H0 and H1, are the same except that some model parameters have fixed value under H0. These models are so called Nested Models. One of the most important examples is detection of a target with unknown amplitude in the clutter. In this problem, one can assume similar models for received signals under H0 and H1 unless the target amplitude is assumed to be zero under H0. If the Bayesian approach used for treating unknown parameters, it can be shown that the likelihood ratio can be calculated as the ratio of the posterior and the prior probability of unknown parameters. Using this method a new detector for detection in Gaussian clutter is presented in this paper. Simulation results show that the proposed detector has much better performance compared with conventional GLRT detectors. It is also shown that a CFAR property is achieved provided that a small modifications in decision rule. Manuscript profile
• Open Access Article
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  4 - Detector Design & Power Allocation of Frequency Diverse Phased Multi Input Multi Output Radar within Nonhomogeneous Environments
  Hamid Reza  Fotoohi Firouzabad Seyed Mehdi Hosseini Andargoli Hossein  Ghanei Yakhdan J. Abouei
  In recent years, Phased-Multiple-Input, Multiple-Output radars (PMRs) have attracted great interest. PMR can combine the advantages of both MIMO radar and phased array radar. Here, PMR transmits orthogonal signals from all subarrays to provide both waveform frequency di More

  In recent years, Phased-Multiple-Input, Multiple-Output radars (PMRs) have attracted great interest. PMR can combine the advantages of both MIMO radar and phased array radar. Here, PMR transmits orthogonal signals from all subarrays to provide both waveform frequency diversity and high coherent processing gain. In this paper dealt with detector design in the presence of heterogeneous clutter based on the unknown scattering coefficients for PMR. Then, detection probability and false-alarm probability are computed based on the derived optimum detector. At the end, the power allocation problem is investigated analytically. The numerical simulations show that obtained optimal detector is joint spatial-temporal filter, which, the clutters are effectively weakened in PMR. Furthermore, simulation results illustrate that proposed power allocation algorithm improve detection performance of PMR in comparison with PR and equal power PMR. Manuscript profile