On the limitation of Vezzosi's subspace rotation method for angle-of-arrival estimation

Vezzosi (Ann. des Telecommun., vol.37, p.425-39, Sept. 1982) proposed an eigenvector (EV) rotation method to resolve multiple signal arrivals to a sensor array and to estimate their angles-of arrival. In the present work it is shown that the model assumed by Vezzosi implies uncorrelated sources, and that the criterion by which the EV rotation is carried out is based on this implicit assumption. The authors present simulation results demonstrating the behavior of the method in a correlated two-source environment with various magnitudes of correlation coefficient, and they show the dependence of the quality of the estimates on the phase of the correlation coefficient. It is concluded that Vezzosi's method is very effective for resolving uncorrelated arrivals. However, it will encounter problems when the arrivals are partly correlated.<>