Underdetermined DOA Estimation of LFM Signals

A method is proposed to separate received LFM signals on underdetermined hypothesis. In which the sensors is less then the signals to be separated. As LFM signal belongs to nonstationary signal, the proposed method is based on Time Frequency Distribution (TFD) analysis. Through suppressing the cross term of the TFD, auto term become prominent. A rotation way utilizing the auto term points is presented, by which the TFD area of each LFM signal is classified. Using the STFD matrices corresponding to the auto term points, the Direction Of Arrival (DOA) of each LFM signal can be estimated individually. Through simulation, it is proved that the proposed method is effective.