为实现旋翼的遥感探测分类与识别, 对基于微多普勒效应的扩展旋翼面目标激光回波特征开展研究。采用物理光学面元法构建了运动扩展旋翼的相干激光探测微多普勒回波模型, 分析计算了旋翼激光角度散射特性, 证明远场条件下旋翼各处回波反射率一致。对三种典型形状旋翼的激光探测回波进行了仿真, 通过平滑伪魏格纳维利(SPWV)变换得到了扩展旋翼的时频特征。电磁散射机理证实各频率带的产生与旋翼结构形状相关, 且桨叶数量以及整体平动速度并不影响旋翼形状在时频图中的特征表达。据此提出了旋翼形状参数的激光探测求解方法, 通过仿真验证了展弦比、根梢比以及桨尖后掠角三种参数算法的正确性, 为后续的旋翼探测识别奠定了基础。

In order to realize the remote sensing detection classification and identification of the rotor, the laser echo feature of extended rotor target based on micro-Doppler effect was studied. The micro-Doppler coherent laser echo model of moving extended rotor was built with the panel method of physical optics. Angular scattering characteristics of laser were analyzed and calculated, which proved that rotor had the same echo reflectivity everywhere under the far field condition. Laser detection echo of three typical rotor shapes was simulated, and the time-frequency features of extended rotor were achieved by Smooth Pseudo Wegener-Villy(SPWV) transform. The electromagnetic scattering mechanism confirms that each frequency band was related to the shape of the rotor, and the number of blades does not affect the expression of features of rotor shape in time-frequency figure as well as the moving velocity. The laser detection calculation methods of rotor shape parameters, including aspect ratio, root-tip ratio and sweep angle of rotor tip, were proposed and proved to be correct through simulation, which layed the foundation for rotor identification.