Dynamic Subarray Beamforming for Angular Superresolution of Coherent Targets

Development of angular superresolution methods for resolving targets using multifunction phased array radar is challenging. Angular superresolution of closely spaced coherent targets with strong interferences in the context of phased array radar has hitherto not been addressed. In this paper a novel beamforming method with angular superresolution is proposed for resolving closely spaced coherent targets in the presence of interferences. A dynamic subarray beamforming framework is first developed based on the knowledge of the number of interferences. The output obtained from the dynamic subarray beamformer is then smoothed using an augmented covariance method to account for the coherence of targets. Superresolution method is then used to obtain robust DOA estimates even at low SNR. Experiments on DOA estimation are conducted in typical target detection scenarios and the results are evaluated using several performance metrics to illustrate the significance of the proposed method.