A Study on Robust Beam-Forming Algorithm for Search Operation in Distributed Array Radar

摘要

A distributed array radar is a radar configuration to form a high-gain receive beam suited to an equivalent large-aperture antenna by arbitrarily distributing and positioning multiple small antennas and coherently synthesizing their received signals. When the placement intervals of the small antennas are sufficiently longer than the wavelength, the conventional beamformer generates many grating lobes and, therefore, ambiguity in the estimated direction of the target. This paper shows that robust Capon beamformer using the norm constraints is effective as a beamforming method that suppresses these grating lobes when using distributed array radar in search radar and prevents a decrease of the search efficiency caused by the reduction in beam width. In addition, an improvement based on diagonal loading is proposed for this algorithm in order to improve the search efficiency. Finally, we consider the parameter optimization and demonstrate the performance using numerical simulation examples.