Direction finding estimation for linear chirp signal

In this paper, we propose a fast maximum likelihood estimation (FMLE) to estimate the direction of arrival (DOA) θ and the frequency sweeping rate (FSR) α of a linear chirp signal impinging upon an M-elements linear sensor array from a far-field source. The estimators θ and α of a chirp signal can be estimated by globally maximizing the likelihood function on the θ~α plane. The global maximum is located on a ridge of the 2-D θ~α plane. To reduce the heavy 2-D ML computation, we propose an algorithm of 1-D FMLE to search for the global maximum only along the ridge