An algorithm for wideband direction of arrival (DOA) estimation based on chirped Z transform (CZT) is proposed.According to the ideally focusing condition of uniform linear array (ULA)

an idea in the wave vector space to solve focusing matrices and the corresponding solution are presented:A row vector in the focusing matrix at the focusing frequency is chosen

as for the focusing matrix of an arbitrary sub-band

the spectrum of the row vector at same position is calculated with CZT

and all vectors are obtained by inverse fast Fourier transform (IFFT).With this method

any value within the signal frequency range can be chosen as the focusing frequency

and good asymptotic unbiased performance can be acquired without any pre-estimated DOA.The validity of these conclusions is validated with computer simulations and pool experiments.