Angle-of-Arrival Estimation for a Rotating Digital Beamforming 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, amplitude comparison angle measurement can be used. Since the digital phased array beam shape is different at each azimuth, each beam is modeled precisely using polynomial curve fitting. Target location is found by comparing amplitudes in adjacent beams. This method assumes targets are seen as single points in the beam pattern, however this assumption no longer holds when the radar is rotating to cover 360 degrees. Extension of the amplitude comparison method for the rotating case is presented in this paper, along with experimental results.