Joint transmit-receive adaptive beamforming experimental results from an auroral-zone Canadian over-the-horizon radar system

New data is presented from an over-the-horizon radar experiment featuring simultaneous multiple transmit channels and multiple receive channels. A joint transmit-receive adaptive beamformer is demonstrated, whereby nulls are placed in the direction of auroral clutter echoes on both transmit and receive. It is shown that the level of the clutter suppression produced by the joint transmit-receive beamformer is the multiplicative product of separate adaptive beamformers on transmit and receive, in accordance with theoretical predictions. The adaptive joint transmit-receive beamformer demonstrates a powerful technique for controlling auroral ionospheric clutter for an over-the-horizon radar airspace surveillance mission.