DIRECTIONS-OF-ARRIVAL ESTIMATIONS OF MULTIPLE COHERENT BROAD-BAND SIGNALS

In the problems of estimating the directions-of-arrival (DOAs) of multiple coherent broadband signals, the coherent signal-subspace (CSS) method [1] and the coherent interpolation (CI) [2] have been proposed. Presented here is the performance comparisons of the two methods along with total least squares estimation of signal parameters via rotational invariance techniques (TLS-ESPRIT) [6], which is a high-resolution narrowband signal-subspace approach to an array system with a translation invariant structure. In the case of unequal-signal powers, the CSS method is not as good as the CI method. Since CI has a disadvantage of larger estimation errors for larger arrival angles, also proposed here is a new spatial phase-shifting technique to improve the performance of CI. Simulation results show the effectiveness of the proposed method.