Adaptive monopulse estimation in mainlobe jamming for non-rectangular planar arrays

Four-channel beams are formed simultaneously in a typical adaptive digital beamforming (ADBF) architecture to cancel mainlobe jamming and maintain monopulse angle estimation accuracy. For large antenna arrays, good performance can also be obtained by performing digital beamforming at sub-array outputs. For non-rectangular array configuration, however, the accuracy of monopulse angle estimation decreases so that the performance of the typical ADBF severely degrades. In this paper, a novel adaptive beamforming architecture is proposed for non-rectangular planar arrays. First, linear compensation is applied to the four-channel beam outputs, and the compensation factor is determined directly from the array configuration. Then, with the scaled monopulse ratio lookup tables, the two-dimensional angles of the target are estimated respectively. Simulation result of a practical phased-array configuration are used to validate the effectiveness of the new method.