Experimental and numerical study of chaff cloud kinetic performance under impact of high speed airflow

Huang, Hesong; Zhongxiang, Tong; Chai, Shijie; Yu, Zhang

doi:10.1016/j.cja.2018.08.002

Cited by 7 publications

(7 citation statements)

References 9 publications

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“…They found that the aerodynamic interferences between elements are mainly related to the overlapping area and the distance among chaff elements during the diffusion process. Their simulation results also show that the chaff elements fully diffuse under the impact of high-speed airflow within 0.5 s. Furthermore, the shape of the chaff cloud is similar to a cone that forms a certain angle with the horizontal plane, and most of the chaff elements are clustered around the second half of the cone [23]. According to these achievements mentioned above, it is an efficient way to study the diffusion and EM scattering properties of the chaff cloud by experiments.…”

Section: A Scattering Evaluation Of the Chaff Cloudmentioning

confidence: 92%

“…At the training stage, Bayesian classifiers are generated by calculating the frequency of the occurrence of each class and the conditional probability of each class for each attribute. According to Bayesian's law P(y i |p) = P(p|y i ) • P(y i ) P(p) (23) where y i is the predicted class that the test range profile belongs to, and p is a dependent vector which is formed according to the features extracted from the range profiles of the plane and chaff cloud by employing the method presented in part A of Section III. Thus, the feature vector p can be written as…”

Section: ) Methods 3: Naïve Bayesian Classificationmentioning

confidence: 99%

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Jamming Efficiency Analysis Based on the Range Profile of Target With Chaff

et al. 2021

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Chaff cloud is widely used in target covering. In this paper, a jamming performance estimation strategy is presented for the elliptical and cubic chaff clouds. The range profiles of the composite models of the plane with the chaff cloud are experimentally accessed in an anechoic chamber using a stepped-frequency waveform measurement system. Then, dimensions, characteristic length, and distributing entropy of the equivalent scattering centers of the plane and the jammer are extracted from the measured range profiles, respectively. Based on these features, support vector machines, naïve Bayesian classification, and decision tree classification methods are employed to determine the recognition rate of the target under the chaff jamming, and then determine the jamming efficiency of the two kinds of chaff clouds. Results show that two types of chaff clouds are able to reduce the target recognition rate. Besides, when the radar uses the Euclidean distance and decision tree classification methods to complete the recognition task, a good jamming efficiency can be achieved by releasing the elliptical or the cubic chaff cloud. Meanwhile, a low level of jamming performance outcomes using the support vector machines classification method. It is also found that the chaff cloud released from the side of the plane achieves a better jamming performance compared with the other releasing locations. Finally, the influence of environmental noise on the recognition rate of the plane is studied. Estimating results show that the recognition rates decrease with the increasing of the power level of the noise. When the transmitting power level of the noise reaches 1.2 times the reflected power level of the target, it is quite hard to estimate the jamming performance of two kinds of chaff clouds.INDEX TERMS Range profile, target recognition, chaff cloud, jamming performance analysis.

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Section: A Scattering Evaluation Of the Chaff Cloudmentioning

confidence: 92%

Section: ) Methods 3: Naïve Bayesian Classificationmentioning

confidence: 99%

Jamming Efficiency Analysis Based on the Range Profile of Target With Chaff

et al. 2021

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“…A 6DOF simulation is usually done by first obtaining the aerodynamic properties and then applying them to the 6DOF equation. In [5] and [6], aerodynamic coefficients were obtained through experiments and applied to the 6DOF of chaff, and the simulation results were compared with the experimental results. The details of the experiment are described in the empirical method.…”

Section: ) 6dofmentioning

confidence: 99%

Chaff Cloud Modeling and Electromagnetic Scattering Properties Estimation

et al. 2023

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Chaff is a radar countermeasure used to interfere with ground radar detection or missile target detection by disrupting the radar. As radar is essential in modern electronic warfare, chaff is also essentially used in many military vehicles. A large amount of chaffs in the form of a thin and long wire is contained in a cylindrical or rectangular cartridge and is launched to form a chaff cloud to disturb the radar. It is virtually impossible to examine the chaff cloud analytically because it is released at once into the air in large quantities. Therefore, for chaff cloud analysis, an approximation method or statistical characteristics are used, or real data is measured directly through experiments. The study of chaff consists of two parts: chaff cloud modeling, which determines the dynamic characteristics of chaff, and estimation of electromagnetic scattering properties, which determines the signal characteristics of the chaff. This review paper focuses on the techniques used in chaff cloud modeling and the estimation of electromagnetic scattering properties. We categorized the techniques by statistical, numerical, and empirical methods. In chaff cloud modeling, studies for the purpose of scattering analysis generally use typical distribution, whereas if chaff cloud modeling itself is the purpose, it is aimed at realizing a realistic chaff cloud by referring to experimental data. For estimation of electromagnetic scattering properties, a conventional method that simply multiplies the average radar cross-section of chaff element to obtain the total radar cross-section of the chaff cloud is used, and a method that allows rapid calculation while considering the distribution of the chaff cloud is being studied.INDEX TERMS Chaff, chaff cloud modeling, electromagnetic scattering properties estimation, radar crosssection, review.

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“…To realistically model the distribution of chaff clouds, numerical methods have been introduced. Zhu et al [8] calculated the equation of motion for chaff by considering the initial velocity due to an explosion, while Huang et al [9] and Wang et al [10] calculated the equation of motion for chaff by considering the aerodynamic interference among chaff fibers using computational fluid dynamics (CFDs). These numerical methods represent the distribution of chaff clouds more realistically than methods using probability distributions but still do not reflect the impact of collisions among chaff fibers.…”

Section: Introductionmentioning

confidence: 99%

Modeling and Dynamic Radar Cross-Section Estimation of Chaff Clouds for Real-Time Simulation

et al. 2023

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Chaff is a passive jammer widely used to disrupt radar or radio-frequency sensors. A mass of chaff fibers dispersed in the air is commonly referred to as a chaff cloud. It is nearly impossible to numerically simulate in real-time the enormous amount of chaff fibers composing the chaff cloud. In this paper, we model the behavior of numerically estimated chaff clouds as probability density functions (PDFs) and apply approximation techniques to estimate the radar cross-section (RCS) of the chaff cloud in real time. To model the aerodynamics of the chaff cloud, we represented the combination of PDFs as functions of time and wind speed. The applied approximation techniques—vector radiative transfer and generalized equivalent conductor method—showed a computation time that cannot be achieved by low-frequency methods such as the method of moments or finite-difference time-domain. Moreover, the dynamic RCS results of the approximation techniques showed a similar trend to those of other studies simulating similar situations. The proposed scheme is effective for real-time chaff cloud simulation, and the modeled dynamics and estimated dynamic RCSs can be a standard baseline for developing new analysis methods for chaff clouds. In the future, the proposed scheme will extend to more chaff fibers and more diverse environmental parameters.

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Experimental and numerical study of chaff cloud kinetic performance under impact of high speed airflow

Cited by 7 publications

References 9 publications

Jamming Efficiency Analysis Based on the Range Profile of Target With Chaff

Jamming Efficiency Analysis Based on the Range Profile of Target With Chaff

Chaff Cloud Modeling and Electromagnetic Scattering Properties Estimation

Modeling and Dynamic Radar Cross-Section Estimation of Chaff Clouds for Real-Time Simulation

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