A method of training a neural network to determine directions of arrival when there are multiple input signals within a narrow frequency band. For a single input signal having a given angle of arrival, an antenna array is used to sample signal values, from which spatial covariance matrix values are obtained. Each value is applied at an input node of the neural network. The neural network is adjusted so that an output node associated with that signal's angle of arrival fires in response to these inputs. This process is repeated for different angles of arrival, such that for L different angles of arrival, L output nodes are trained with L different training sets of data. Once trained, the neural network can be used in a direction finding system that detects whatever number of signals are present in a received wavefield having any number of signals.
Richard L. Johnson; William J. Montville