Improved azimuth accuracy for a Digital Beamforming perimeter surveillance radar

In Digital Beamforming (DBF) radars, multiple beams are formed simultaneously at different azimuth and/or elevation angles to monitor large areas of interest. In order to estimate the location of a target in azimuth without specifically steering the beams at the target or using special techniques such as monopulse, simple centroid schemes can be used. This assumes that a target is seen by more than one beam, which requires the beam pattern to be somewhat overlapping and that the Signal-to-Noise Ratio (SNR) of the target is sufficient. In this paper, a new azimuth centroid computation scheme using amplitude comparison is presented. Since the digital phased array beam shape is different at each azimuth, each beam is modeled by simple polynomial curve fitting. Simulation and preliminary experimental results show that the proposed method gives better azimuth accuracies compared to other centroid techniques.