直升机旋翼叶片回波建模与特性分析

Modeling of helicopter rotor blades' echoes and its characteristic analysis

为提高直升机等具有微动特征目标的识别能力,对直升机旋翼叶片的微动特性进行了综合研究.首先基于旋翼叶片所有散射点都会产生回波这一事实,构建回波的散射点积分数学模型;其次基于该模型对回波在时域、频域的闪烁现象及原因进行了分析;最后对叶片数目奇偶性、初始旋转角、旋翼转动频率等参数和回波闪烁现象、微多普勒特征之间的关系作了理论分析和仿真实验.仿真结果表明,与矩形平板模型相比,散射点积分模型与目标闪烁情况吻合较好,更有利于提取微多普勒特征,为进一步识别直升机类目标提供了理论依据.

To improve the capability of helicopters identifying the targets with the micro-motion features, this article studies comprehensively the micro-motion characteristics of helicopters＇ rotor blades. Firstly, based on the facts that all the scattering points would produce the echoes, it establishes the integral math model for those scattering points of echoes, based on which, next, it analyzes the echoes＇ scintillation and its cause in time domain and frequency domain, and finally, it carries on the theoretical analysis and performs the simulation experiments on the parity of blades＇ number, the initial rotation angle, the rotor revolving speed parameters and the relationship between the scintillation and micro-Doppler characteristics of echoes. Simulation results show that the integral model of scattering points coincides with the scintillation of target better, compared to the rectangular slab model,and makes for extracting the micro-Doppler characteristics, thus offering a theoretical basis for further identifying the targets of helicopter class.