Description: Current state of investigations of secondary modulation of radar signal reflected by air objects is analyzed. Method of numerical modeling of scattering characteristics of air target with turbo-prop engines and also fluctuation spectra of signals scattered by stated objects is considered. Earlier developed by authors high-frequency asymptotic method based on estimation of contributions of the smooth and edged segments of object surface to complete scattered field is used for modeling. Results of calculations of helicopter radar cross section and propeller modulation spectra are demonstrated. Potentialities of using of a helicopter propeller modulation spectrum for obtaining additional radar information about such targets for their recognition are discussed.
Keywords: air target recognition, mathematical modeling of radar air target secondary emission characteristics, radar cross section, spectrum of propeller modulation