a single aperture antenna having at least one driven element with at least two fundamental modes that can be used to derive angle-of-arrival measurements for received signals;

a plurality of load circuits embedded either in the radiation aperture of the antenna or behind a ground plane of said antenna, said load circuits having impedance characteristics that are either (a) predetermined and fixed or (b) variable by changing the values of electrical control signals applied to active components within the load circuits;

a controller configured to select for use a subset of said load circuits to effect operation in at least one of said fundamental modes and which updates control settings of selected load circuits having variable impedance and belonging to said subset, if any;

means for measuring received signal angle-of-arrival by converting measured output signals of said at least two fundamental modes of said antenna into said angle-of-arrival measurements for the received signals;

means for maintaining tracks by creating new tracks for the received signals with said angle-of-arrival measurements that are statistically inconsistent with angle-of-arrival estimates of previously existing tracks, and by eliminating said existing tracks that are statistically inconsistent with said angle-of-arrival measurements;

means for tracking and updating said existing tracks to provide estimates of the dynamics for a point-of-origin of each of said received signals based on the angle-of-arrival measurements of the received signals and measured or estimated dynamics of said antenna system; and

means for estimating received angles-of-arrival by computing the angle-of-arrival estimate for said existing tracks based on relative dynamics of said antenna system and the point-of-origin of each of said received signals.