Abstract: An array of detector elements located at the focal plane of an antenna system can be used to reduce or eliminate the influence of glint induced tracking errors and increase the field-of-view of angle-of-arrival detection systems. The array at the focal plane is divided into four quadrants. Each quadrant has its own receive channel to detect the amplitude of the signals focused on that quadrant. The resulting amplitude signals are compared in pairs for diagonally opposite quadrants to develop two error signals (i.e., elevation and azimuth). This noncoherent detection is equivalent to an optical quadrant detector.