旋翼微多普勒特性实验分析

为分析旋翼及其主要部件的微多普勒效应特点，提出了一种通过微波暗室进行旋翼微多普勒效应测试的实验方法，并通过实例验证了实验方法的可靠性；两种桨叶不同桨叶片数的系列实验结果表明，旋翼的微多普勒特性通过频率把各个散射部件的回波能量分开，旋翼的片数和转速不影响微多普勒特性的分析估算，旋翼的微多普勒特性仅与其运动特性相关；结合直升机目标识别特征，采用短时傅里叶变换方法对实验数据进行微多普勒效应提取，分析了微多普勒效应与入射波和旋翼几何属性之间的关系，得到了旋翼微多普勒效应的频率特性、极化特性和宽频带特性.

Experimental analysis on micro-Doppler characteristics of rotors

In order to analyze the micro-Doppler effect of rotor and its main parts, a measurement method using microwave anechoic chamber was suggested, and its reliability was verified by some examples. A series of experiments on some rotors with two kinds of blades and with different numbers of blades indicate that echoes of various scattering components can be separated by frequency in the micro-Doppler effect. The number of blades and the rotation speed of rotor do not affect the analysis and estimate of the micro-Doppler effect. It can also be concluded that the micro-Doppler effect only depends on the motion characteristic of the rotor. Combined with target characteristics of helicopter, micro-Doppler effect of rotor was extracted from experimental data using short fast Fourier transform, and the frequency characteristic, wide frequency band and polarization characteristic were obtained by analyzing the influences of incident wave and geometry characteristics of rotor on micro-Doppler effect.