Abstract: System and method for finding a direction of two or more secondary RF sources arrayed about a position of a primary RF source (X1). The system includes an antenna system (500) coupled to a monopulse tracking system (100) for determining a position of a primary RF source relative to a boresight axis (502) of the antenna system. The system includes a monopulse direction finding system (600) coupled to the antenna system responsive to RF signals from two or more secondary RF sources (Y1, Y2) having at least one of a different frequency and a different polarization as compared to the primary RF source.

Abstract: A phased array antenna has a spatially periodic array of tapered pitch helical antenna elements disposed on a first side of a panel, and RF interface circuitry on a second side the panel. For a ‘pseudo’-monopulse tracking mode of operation, single bit, digitally controlled phase shift elements of the RF circuitry impart sequentially different amounts of phase shift to the energy derived from the spatial sections of the antenna elements. This causes a sequential electrical tilting of the beam pattern of the array in a plurality of respectively different directions relative to boresight. For each sequential tilt of the beam pattern, signals representative of the energy received by each of plural quadrants of the array are summed and stored.