Wideband maximum likelihood direction finding and signal parameter estimation by using the tree-structured EM algorithm

The expectation maximization (EM) algorithm is presented for the case of es timating direction of arrivals of unknown deterministic wideband signals, A lternative regularized least squares estimation techniques for the required signal estimation and a tree structure for the data mapping in the Ehl alg orithm are proposed. Extensive simulation results are presented for compari son of the proposed algorithms with the conventional EM approach and the cu rrent high-resolution methods of wideband direction finding.