High resolution direction finding by structured covariance matrix matching

The author develops a high-resolution method for estimating the angles-of-arrival of multiple, possibly correlated, stochastic signal sources based on a least-squares structured covariance matrix matching criterion. It is shown that this approach results in a separable solution, with the angle estimates being obtained by maximizing a function over only the angle parameters. The source covariance matrix estimate is obtained by an explicit closed-form formula. The method results in a substantial reduction of the parameter set required for numerical optimization compared to previous approaches based on direct maximization over all unknown parameters. Computer simulation results are presented to demonstrate the performance of the proposed methods