Spatial spectrum for direction of arrival estimation of multiple non-stationary wideband sources in the time-frequency plane

A spatial spectrum function for estimating direction of arrival (DOA) of multiple and non-stationary wideband sources using a sensor array is proposed. The sensor array output signal is converted into the time–frequency (TF) array signal and the signal at each frequency bin is converted into the signal at the reference frequency using the focusing matrix. Then DOA is estimated by forming a novel spatial spectrum using the joint diagonalisation structure of spatial TF distribution matrices at auto-term points and by searching its peak points. Unlike the subspace-based high-resolution DOA estimation techniques, suggested method has no need of determining the number of sources and is applicable even when the number of sources is equal to the number of sensors.