Time-frequency harmonic wave analysis method of composite micro-Doppler signals.

In the time-frequency analysis of the echoes from targets with composite micro-motions, there is a problem that the energy of time-frequency strip is difficult to focus, which affects the extraction and analysis of the target's micro-Doppler feature. To solve this problem, this paper proposes the concept of time-frequency harmonic stripes and corresponding time-frequency transformation methods. Based on the assumption that the composite micro-motions include central motion components and high-frequency motion components, firstly, spline function is used to fit the frequency curve of the central motion component, and therefore construct the time-frequency transform kernel is constructed. Then, parameterized time-frequency transform is used to convert the composite micro-Doppler signal in the time domain to harmonic stripes on the time-frequency plane. Compared with traditional methods such as short-time Fourier transform and pseudo Wigner-Ville distribution, the proposed method can significantly improve the energy aggregation and spur suppression of time-frequency transform of radar echoes from composite micro-motion targets. Simulation results verify the effectiveness of the proposed method and its adaptability to low signal-to-noise ratio (SNR) conditions. [ABSTRACT FROM AUTHOR]