Enhanced direction of arrival estimation via reassigned space-time-frequency methods

Two new space-time-frequency direction of arrival estimation algorithms are presented that decrease the estimation variance under specific conditions of narrow differential direction of arrival when multiple signals impinge upon the sensor array. The first algorithm, called Wide-Lane, provides a modest extension of existing space-time-frequency (STF) techniques by integrating a wide path along the signal´s instantaneous frequency track through the time-frequency (TF) plane. The second algorithm, called Reassigned STF, utilizes the TF reassignment method to increase the signal´s localization within the TF plane prior to estimating the direction of arrival with MUSIC. The performance variation of space-time MUSIC to a variety of signal structures is also presented.