Joint estimation of Doppler and multipath time delay of overlapping echoes for LFM pulse radar

A new method for estimating the Doppler and multipath time delay of the overlapping linear-frequency modulated (LFM) signal returned echoes for pulse radar by using only one period pulse signal is presented. First, the Doppler frequency is estimated by the Wigner-Hough transform. Then, a reference signal is reconstructed using prior knowledge of the transmitted signal and the frequency parameters. Finally, using the property that the Wigner-Ville distribution can separate each echo from the overlapping echoes in the time-frequency plane, the multipath time delay is obtained by a so-called "modified time-frequency correlation function" proposed in this paper. The proposed method is characterized by the stronger robustness against additive Gaussian noise and the lower computational cost.