Stealth Research Of Armed Helicopter Based On RCS Numerical Calculation And Optimization

Due to the relatively slow speed of helicopter and the obvious Doppler characteristics of rotor movement, stealth design of helicopter is particularly important when faced with the threat of radar-guided weapons. As China's new generation dedicated armed helicopter coming into service, radar stealth research of armed helicopter will become one of research focuses in helicopter engineering field. In this paper, the numerical calculation methods have being taken to calculate and analyze the RCS of armed helicopters. These methods include RCS calculation of general complex targets based on physical optics and equivalent electric currents method, time-frequency domain RCS image calculation of helicopter rotor based on time-frequency analysis method, and finally the RCS reduction of armed helicopter fuselage shape optimization method based on genetic algorithm.Firstly, the numerical method based on PO and MEC is taken to calculate the RCS of stealth and non-stealth armed helicopter fuselages. The spatial distribution of radar scatter echo of stealth helicopter fuselage and helicopter stealth configuration design principles have been analyzed. In addition, under the principle of quasi-stationary method, helicopter rotor RCS on time domain and frequency domain is calculated. And time-frequency domain RCS grayscale images of three types of rotor are calculated using time-frequency domain analysis method. By analysis and comparison of time-frequency domain RCS images and time-frequency domain characteristics, a method of identify the number of rotor blades through rotor radar echo is obtained. Meanwhile, the principles of RCS reduction on helicopter rotor are analyzed theoretically.Finally, a RCS reduction shape optimization method based on genetic algorithm is established combining parameterized modeling with genetic algorithm. A simple shaped target example is taken to demonstrate the effectiveness of this method. Further more, this method is taken to optimize configuration of armed helicopter fuselage in order to reduce the RCS on specific angle range of nose direction. The low RCS helicopter fuselage configuration is obtained and some significant conclusions are acquired for armed helicopter fuselage stealth design.