Analysis and evaluation on RCS characteristics of helicopter considering modulated effect of rotor

Considering the modulated effect of rotor, a panel-edge method suitable for solving radar cross section (RCS) characteristics of the whole helicopter was developed. In order to improve grid generating quality of large shape changes, the high density grids were generated considering the accuracy and efficiency. Simultaneously, the density and scale of electromagnetic grids need to meet the radar wave length ratio. The blade pitching and flapping motions were included by inclination of disk, and the RCS characteristics of the whole helicopter effected by rotor were simulated by the quasi-static method. Then calculations and simulations on RCS of an helicopter about the polarization, attitude and frequency responses were carried out. According to the relationship between RCS of helicopter and detecting distance of radar, four-stage warning mechanism and angle domains were presented. The results show that the RCS dynamic responses of the whole helicopter is continuous and symmetric considering the rotating rotor, and the oscillation scattering is strong, with the amplitude of RCS between -5 to 12dB ·m². Compared with even blades, the RCS of odd blades is reduced from 2 to 5dB ·m², and the RCS envelope and time domain responses of scattering peak are controlled. Finally, the radar stealth performance can be improved.