Robust Beamforming for Jammers Suppression in MIMO Radar

Robust beamforming for multiple-input multiple-output (MIMO) radar in the background of powerful jamming signals is investigated in this paper. We design two minimum variance distortionless response (MVDR) type beamformers with adaptiveness/robustness against the powerful jammers for colocated MIMO radar. Specifically, the MVDR beamformer is firstly designed for known jammers in the sector-of-interest, which maintains distortionless response towards the direction of the target while imposing nulls towards the directions of jammers. Then the adaptive/robust MVDR beamformer is designed for the general case of unknown in-sector jammers and/or out-of-sector interfering sources. Convex optimization techniques are used in both of the designs. Moreover, we derive a closed-form solution to the simplified second design. Based on this solution, we derive efficient power estimates of the desired and/or interfering sources in the context of powerful jammers and non-ideal factors such as array calibration errors and target steering vector mismatches. We demonstrate that the capability of efficient jammers suppression using these designs is unique in MIMO radar.