DMRA: An Adaptive Line Spectrum Estimation Method Through Dynamical Multiresolution of Atoms

We proposed a novel dense line spectrum super-resolution algorithm, the DMRA, that leverages dynamical multi-resolution of atoms technique to address the limitation of traditional compressed sensing methods when handling dense point-source signals. The algorithm utilizes a smooth <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">tanh</monospace> relaxation function to replace the <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">l₀</monospace> norm, promoting sparsity and jointly estimating the frequency atoms and complex gains. To reduce computational complexity and improve frequency estimation accuracy, a two-stage strategy was further introduced to dynamically adjust the number of the optimized degrees of freedom. Theoretical analysis were provided to validate the proposed method for multi-parameter estimations. DMRA presents excellent performance for the super-resolution of cluster-sparse signals, which is a typical scenario in different practical applications. It also outperforms the state-of-the-art methods in terms of frequency estimation accuracy and computational efficiency.