| The chaff cloud is one of the passive jammings that is widely used in the areas of anti-ship, anti-missile and electronic countermeasure (ECM), hence the research of electromagnetic properties of the chaff cloud is of great importance to the military operational capacity improvement. Furthermore, with the development of computer technology, the computer simulation has become an efficient tool for the analysis of the chaff cloud. Thus, the main research of this article is as follows:Firstly, the modeling and electromagnetic scattering properties of the chaff cloud are investigated. In order to accelerate the modeling process, the octree grouping technique is employed to accelerate the process of checking the intersection. The multilevel fast multipole algorithm (MLFMA) is used to calculate the scattering matrix and the radar cross section of the chaff cloud. In order to further accelerate the matrix equation iterative solving, a preconditioner based on the power series expansion is proposed to improve the MUMPS preconditioner. Numerical examples are given to show the efficiency of the proposed method.Secondly, the motion and Micro-Doppler spectral characteristic of the chaff cloud are researched. The speed and position of the chaff under the influence of the change in the angle between chaff and vertical direction is analyzed, and then the space distribution of chaff cloud movement under different throwing is discussed. In the end Micro-Doppler frequency shift characteristics of chaff cloud is considered. The echo signal model of the chaff cloud with the attitude of translational and micro motion is established, and the effect of the different wind speed, the rotating angular velocity, transmission frequency to the Doppler characteristics of chaff cloud is discussed. Numerical examples are presented to show the accuracy of the proposed method. |
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