Advanced Direction-of-Arrival Estimation in Coprime Arrays via Adaptive Nyström Spectral Analysis

This letter introduces Adaptive Nyström Spectral Analysis (ANSA) as a new technique for Direction of Arrival (DOA) estimation in coprime arrays. ANSA exploits Nyström-based root-MUSIC, employing matrix decomposition, polynomial root-finding, and adaptive noise subspace construction. The extended coprime array configuration, comprising distinct subarrays strategically positioned with physical sensors, adeptly captures uncorrelated far-field narrowband sources. ANSA significantly enhances direction-of-arrival (DOA) estimation accuracy, particularly in scenarios with high signal-to-noise ratio (SNR), while demonstrating robustness against parameter variations. A comprehensive analysis, incorporating the Cramér–Rao bound (CRB), substantiates ANSA's performance by establishing a stringent lower bound on the variance of the DOA estimator. This approach underscores exceptional potential for coprime arrays across varied signal environments, delivering a blend of precision and computational efficiency.