Adaptive Sum and Difference Beamforming for Monopulse System with Array Antennas

Adaptive beamforming will distort monopulse ratio curve and influence angle estimation performance of monopulse system with array antennas. A constrained adaptive beamforming algorithm is proposed, which is implemented in a general side-lobe canceller structure. A reduced-rank blocking matrix is constructed to reduce computational complexity, and additional constraints are introduced to maintain the main-lobe of sum and difference patterns. Simulation results show that the proposed algorithm can suppress interferences effectively and control distortion degree of monopulse ratio curve.