基于散射电场的飞机旋翼多普勒回波模拟

旋翼飞机飞行过程中会产生具有独特多普勒特征的雷达回波,通过对旋翼回波的准确模拟,可为不同类型飞机的精确识别提供重要依据.针对现有散射点叠加算法的假设缺陷,从目标高频电磁散射理论出发,提出了基于散射电场的飞机旋翼回波模拟方法.依据电磁散射场与雷达回波方程间的数学关系,发现目标回波的基带信号与目标后向散射电场的复振幅矢量具有一致性,基于此采用物理光学—矩量混合算法,求解飞机旋翼的散射电场;并通过短时傅里叶变换模拟得到旋翼的时频回波.最后,通过与传统散射点积分算法进行仿真对比,同时分析了不同桨叶角对旋翼回波信号的影响规律,验证了所提方法的正确性和优越性,实现了散射电场下飞机旋翼多普勒回波的准确获取,为后续研究飞机的精确识别奠定了理论基础.

Doppler Echo Simulation of Aircraft Rotor Based on Scattering Electric Field

Radar echoes with unique doppler characteristics are generated during the rotorcraft flight. By accurately simulating target echoes, it provides an important basis for the accurate identification and classification of different types of aircrafts. Aiming at the hypothesized defect of the existing scattering-point integral algorithm, a rotor blade echo simulation method based on scattering electric field is proposed from the theory of high frequency electromagnetic scattering. According to the mathematical relationship between the radar echo and the scattering electric field, the consistency of the target echo signal and the baseband signal with the complex amplitude vector of the target backscattering electric field was found. Based on this, the physical optics-moment hybrid algorithm is used to solve the scattering electric field of the aircraft rotor, and the time-frequency characteristics of the echo are obtained by the short-time Fourier transform. Finally, by comparing the traditional scattering point integration algorithm, the influence of different blade angles on echo signals is analyzed and the correctness and superiority of the proposed method are verified. The accurate acquisition of doppler echo of aircraft rotor under the scattering electric field is realized. It provides certain application value for the identification and classification of target aircraft.