Adaptive Robust Capon Beamforming with enhanced beam continuity

MVDR (Minimum Variance Distortionless Response) beamforming is widely used for its high-resolution capability in suppressing interference and noise. However, it is highly sensitive to steering vector errors, which can occur due to environmental uncertainties or calibration issues. Even small deviations in the steering vector can result in significant performance degradation, which can reduce the reliability of MVDR in situations where deviations occur frequently or channel variability is high. Robust Capon Beamforming (RCB) was previously developed to address this issue. RCB provides greater robustness by increasing the tolerance to steering vector errors. While it results in a more robust beamform compared to MVDR, it nevertheless has its limitations. In particular, even if the robustness is increased by moderately increasing the beamwidth by tolerating errors, the possibility of beam discontinuities appears in the beamforming. This discontinuity can be a serious problem for situations where the reliability of signal tracking is important. To solve this problem, we propose an adaptive RCB method. The proposed method can secure both robustness and beam continuity by adjusting the parameter based on the beamforming results. This method improves the practicality of RCB even in relatively uncertain environments by maintaining tracking in a specific desired direction.