飞机旋转叶片回波频谱特征分析

飞机目标发动机叶片的周期性旋转运动导致目标散射回波中出现周期性运动部件调制频谱分量,在某些姿态下该频谱分量幅度呈sinc(x)包络状,并不对称分布于机体多普勒频谱分量一侧。为揭示这一现象,在对旋转叶片组建立电磁散射模型和对风扇目标进行试验测量基础上,分析了叶片长度、倾斜角和扭角等结构参数对周期性运动部件调制频谱分量分布规律的影响。结果表明叶片扭角是导致该现象出现的主要原因。

Analysis of the spectrum signature of the radar return signal from aircraft rotating blades

The periodic rotation movement of aircraft engine blades will cause modulation spectral components on the radar return signals. The amplitude of these components in some aspects is similar to the envelope of function sinc(x),distributing over one side of the Doppler frequency of the fuselage asymmetrically. In order to reveal such a phenomenon, the effects of the structural parameters, such as blade length, pitch angle and twist angle, are analyzed based on both the electromagnetic scattering computation and measured fan data. The results show that the blade twist is the main reason for the phenomenon.