Estimation of direction of arrival for wideband coherent signals with known waveforms

A direction of arrival (DOA) estimator for wideband coherent signals with known waveforms and unknown amplitude is presented in this paper, which is extended from the estimation algorithm for time delay, referred to as WRELAX. The method can be called coherent space-time RELAX (CST-RELAX), which is a relaxation-based minimizer of a complicated nonlinear least squares cost function and is implemented in both space and time domain. Numerical examples in the presence of white and colored noise respectively are provided to demonstrate its performance and compare with other well-known algorithms including CSM (coherent subspace method) and wideband RELAX. The proposed method improves the estimation accuracy and has an excellent resolution.