List of Articles Radar

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  1 - Target Tracking in MIMO Radar Systems Using Velocity Vector
  Mohammad Jabbarian Jahromi Hossein Khaleghi Bizaki
  10.7508/jist.2014.03.003
  The superiority of multiple-input multiple-output (MIMO) radars over conventional radars has been recently shown in many aspects. These radars consist of many transmitters and receivers located far from each other. In this scenario, the MIMO radar is able to observe the More

  The superiority of multiple-input multiple-output (MIMO) radars over conventional radars has been recently shown in many aspects. These radars consist of many transmitters and receivers located far from each other. In this scenario, the MIMO radar is able to observe the targets from different directions. One of the advantages of these radars is exploitation of Doppler frequencies from different transmitter-target-receiver paths. The extracted Doppler frequencies can be used for estimation of target velocity vector so that, the radar can be able to track the targets by use of its velocity vector with reasonable accuracy. In this paper, two different processing systems are considered for MIMO radars. First one is the pulse Doppler system, and the second one is continuous wave (CW) system without range processing. The measurement of the velocity vector of the target and its counterpart errors are taken into account. Also, the extended Kalman target tracking by using its velocity vector is considered. Besides, its performance is compared with those of MIMO target tracking without using the velocity vector and conventional radars. The simulation results show that the MIMO radars using velocity vector have superior performance over other above-mentioned radars in fast maneuvering target tracking. Since the range processing is ignored in CW MIMO radar systems, the complexity of this system is much lower than that of Pulse Doppler MIMO radar system, but has lower performance in tracking fast maneuvering target. Manuscript profile
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  2 - 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
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  3 - A Bias-reduced Solution for Target Localization with Distance-dependent Noises in Illuminator of Opportunity Passive Radar
  حبیب راثی Maryam Shirzadian Gilan
  10.7508/jist.2019.01.001
  A closed-form solution for target localization based on the realistic distance-dependent noises in illuminator of opportunity passive radar and the reduction method of the bias which exists in the two-stage weighted least squares (2SWLS) method is proposed. 2SWLS is a c More

  A closed-form solution for target localization based on the realistic distance-dependent noises in illuminator of opportunity passive radar and the reduction method of the bias which exists in the two-stage weighted least squares (2SWLS) method is proposed. 2SWLS is a classic method for time-of-arrival (TOA) and frequency-of-arrival (FOA) localization problem and has a couple of improved solutions over the years. The 2SWLS and its improved solutions have great localization performances in their established location scenarios on the basis of two approximations that setting the noise to a constant and ignoring the high-order terms of TOA and FOA measurement noises. It is these two approximations that lead to a sub-optimal solution with bias. The bias of 2SWLS has a significant influence on the target localization in illuminator of opportunity passive radar that has lower measurement accuracy and higher noises than active radar. Therefore, this paper starts by taking into consideration of the realistic distance-dependent characteristics of TOA/-FOA noises and improving 2SWLS method. Then, the bias of the improved 2SWLS method is analyzed and bias-reduced solution based on weighted least squares (WLS) is developed. Numerical simulations demonstrate that, compared to the existing improved solutions of the 2SWLS, the proposed method effectively reduces the bias and achieves higher localization accuracy. Manuscript profile
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  4 - SQP-based Power Allocation Strategy for Target Tracking in MIMO Radar Network with Widely Separated Antennas
  Mohammad  Akhondi Darzikolaei Mohammad Reza Karami-Mollaei Maryam Najimi
  10.52547/jist.9.36.21
  MIMO radar with widely separated antennas enhances detection and estimation resolution by utilizing the diversity of the propagation path. Each antenna of this type of radar can steer its beam independently towards any direction as an independent transmitter. However, t More

  MIMO radar with widely separated antennas enhances detection and estimation resolution by utilizing the diversity of the propagation path. Each antenna of this type of radar can steer its beam independently towards any direction as an independent transmitter. However, the joint processing of signals for transmission and reception differs this radar from the multistatic radar. There are many resource optimization problems which improve the performance of MIMO radar. But power allocation is one of the most interesting resource optimization problems. The power allocation finds an optimum strategy to assign power to transmit antennas with the aim of minimizing the target tracking errors under specified transmit power constraints. In this study, the performance of power allocation for target tracking in MIMO radar with widely separated antennas is investigated. Therefore, a MIMO radar with distributed antennas is configured and a target motion model using the constant velocity (CV) method is modeled. Then Joint Cramer Rao bound (CRB) for target parameters (joint target position and velocity) estimation error is calculated. This is utilized as a power allocation problem objective function. Since the proposed power allocation problem is nonconvex. Therefore, a SQP-based power allocation algorithm is proposed to solve it. In simulation results, the performance of the proposed algorithm in various conditions such as a different number of antennas and antenna geometry configurations is examined. Results affirm the accuracy of the proposed algorithm. Manuscript profile
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  5 - A New Approach to Compress Multicarrier Phase-Coded Radar Signals
  R. mohseni a. sheikhi m.a. masnadi shirazi
  Multicarrier phase coded signals have been recently introduced to achieve high range resolution in radar systems. As single carrier phase coded radars, the common method for compression of these signals, is using matched filter or computing the auto correlation function More

  Multicarrier phase coded signals have been recently introduced to achieve high range resolution in radar systems. As single carrier phase coded radars, the common method for compression of these signals, is using matched filter or computing the auto correlation function directly. In this paper we propose a new method based on fast Fourier transform (FFT) with lower computational load with respect to traditional approach. Furthermore, based on this new approach, a method for estimation of communication channel is introduced that can be used for improving detection performance and target position estimation in tracking mode. Manuscript profile
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  6 - Covariance Matrix Design for SINR Enhancement in Presence of Signal-Dependent Interferers
  M. Bolhasani S. Imani S. A. Ghorashi
  In this paper, the problem of covariance matrix design to increase signal-to-interference-plus-noise ratio (SINR) in receiver for multiple-input multiple-output (MIMO) radars is considered. Our goal is to design a covariance matrix which can suppress more interferers co More

  In this paper, the problem of covariance matrix design to increase signal-to-interference-plus-noise ratio (SINR) in receiver for multiple-input multiple-output (MIMO) radars is considered. Our goal is to design a covariance matrix which can suppress more interferers compared to phased array radar and recent covariance matrix design methods. It can also result in a better SINR level compared to conventional MIMO radars. In this paper, maximum SINR of the proposed covariance matrix is calculated in closed form. Simulation results show that our proposed covariance matrix in addition to achieve better SINR performance, can suppress more interferers compared to phased array radar and recent covariance matrix design methods, by using waveform diversity with the same number of antennas. Simulation results also validate analytical achievements that presented in this paper. Manuscript profile
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  7 - Space Time Code Design in Phased-MIMO Radars to Achieve High Resolution in Board and Velocity
  Roholah Vahdani Hossein Khaleghi Mohsen Fallah Joshaghani
  In this paper, space-time codes for MIMO radar are used to achieve high resolution at target range and speed. The two-dimensional ambiguity function is known as a tool to compare radar performance in terms of resolution. A space-time code can be designed based on minimi More

  In this paper, space-time codes for MIMO radar are used to achieve high resolution at target range and speed. The two-dimensional ambiguity function is known as a tool to compare radar performance in terms of resolution. A space-time code can be designed based on minimizing the distance between the actual target parameters in range, speed and angle. For this purpose, high resolution can be achieved by analyzing the ambiguity function and narrowing it down as much as possible. In this paper, the ambiguity function with two variables of amplitude and speed mismatch is considered and a new criterion to achieve high resolution performance in this field is proposed. In this case, by optimizing the proposed cost functions, the optimal space-time code is extracted. The proposed design can also be extended to phased-MIMO radar. The simulation results also show that our proposed scheme has a very narrow ambiguity function around the origin, while it has a performance very close to the optimal state in terms of target identification probability. Manuscript profile
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  8 - 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
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  9 - A New Power Allocation Optimization for One Target Tracking in Widely Separated MIMO Radar
  Mohammad Akhondi Darzikolaei Mohammad Reza Karami-Mollaei Maryam Najimi
  10.61186/jist.39531.11.44.294
  In this paper, a new power allocation scheme for one target tracking in MIMO radar with widely dispersed antennas is designed. This kind of radar applies multiple antennas which are deployed widely dispersed from each other. Therefore, a target is observed simultaneousl More

  In this paper, a new power allocation scheme for one target tracking in MIMO radar with widely dispersed antennas is designed. This kind of radar applies multiple antennas which are deployed widely dispersed from each other. Therefore, a target is observed simultaneously from different uncorrelated angles and it offers spatial diversity. In this radar, a target’s radar cross section (RCS) is different in each transmit-receive path. So, a random complex Gaussian RCS is supposed for one target. Power allocation is used to allocate the optimum power to each transmit antenna and avoid illuminating the extra power in the environment and hiding it from interception. This manuscript aims to minimize the target tracking error with constraints on total transmit power and the power of each transmit antenna. For calculation of target tracking error, the joint Cramer Rao bound for a target velocity and position is computed and this is assumed as an objective function of the problem. It should be noted that a target RCS is also considered as unknown parameter and it is estimated along with target parameters. This makes a problem more similar to real conditions. After the investigation of the problem convexity, the problem is solved by particle swarm optimization (PSO) and sequential quadratic programming (SQP) algorithms. Then, various scenarios are simulated to evaluate the proposed scheme. The simulation results validate the accuracy and the effectiveness of the power allocation structure for target tracking in MIMO radar with widely separated antennas. Manuscript profile