Measurement method for repetition frequencies of the blades of an aerial vehicle on the base of the convolution of the «secondary» modulation spectrum

Abstract

A novel measurement method for repetition frequencies of the blades of an aerial vehicle (in part, helicopter's main and tail rotor) for adaptation circuits of the radar sensor with an inverse synthesis of antenna aperture is proposed. The method based on the convolution of the spectrum of the «secondary» modulation of the signal with simultaneous compensation of the Doppler frequency of the reflected signal. This allows in typical conditions for the radar sensor rapid change of Doppler frequency to provide a long coherent accumulation and, accordingly, high accuracy of measurement of the rotational frequencies of the rotors.

Keywords

• rotational frequency
• repetition frequency of the blades
• main rotor
• tail rotor
• helicopter