Method of stepped frequency signal processing based on fractional Fourier transform

This paper proposes a method of the stepped frequency signal processing based on fractional Fourier transform. Conventional IDFT processing of stepped frequency signal without velocity compensation will cause high resolution range profile aberration, thus reduce the detection performance. As the echo wave of the moving target in Doppler dimension can be considered as chirp form, so high resolution range can be obtained by detecting and estimating the parameters of the chirp signal through fractional Fourier transform (FRFT). As a linear transform, the FRFT avoids the cross term interference while dealing with multi-component signals. The method based on FRFT does not need velocity compensation, furthermore it realize the combinational estimation of the high resolution range and velocity of the target. Fast algorithm of the FRFT is adopted in this paper, which makes the computations of the FRFT be comparable to that of FFT. Simulation results and experiments on real data show the efficiency and validity of the proposed method.