Abstract

Background: Chirp signals are widely applied in radar systems, biomedicine, seismic prospecting and many other fields. It is difficult to estimate fast and accurately original frequency and chirp rate of chirp signals because of the existence of stable noise in the echo signals.

Methods: In this paper, a parameter estimation method for chirp signals is proposed. Firstly, the impulse characteristics of stable noise in the echo signals is suppressed. Secondly, chirp rate of chirp signals is easily calculated by Quadratic Phase Function (QPF) method and the order of Fractional Fourier Transform (FRFT) can be determined.

Results: Finally, the original frequency of chirp signals can be estimated by FRFT method. Simulation results demonstrate that the proposed method can achieve higher accuracy than the single FRFT method and the running speed of the proposed method is nearly three times faster than the single FRFT method.

Keywords: α Stable noise, chirp signal, fraction fourier transform, quadratic phase function, weaken impulse.

Graphical Abstract