OTHR Phase-Only Beamformer Drone-Based Measurements

The Defence Research and Development Canada (DRDC) antenna measurement drone was used to evaluate the beamforming performance of the Ottawa experimental OTHR transmit antenna array. Optimal and phase-only beamformers were compared and various calibration approaches were used with the intent of maximizing power toward a target and minimizing power toward the auroral clutter. Phase-only beamforming gave 7.5 dB more power on target than optimal beamforming. Surprisingly, theoretical calibration appeared to give better results than experimental calibration, making the far-field calibration task significantly easier.