Joint DoA-Range Estimation Using Space-Frequency Virtual Difference Coarray

In this paper, we address the problem of joint direction-of-arrival (DoA) and range estimation using frequency diverse coprime array (FDCA). By incorporating structure offsets, a two-dimensional space-frequency virtual difference coarray corresponding to uniform offset is considered increase number degrees-of-freedom (DoFs). However, reconstruction doubly-Toeplitz covariance matrix computationally prohibitive. To solve problem, propose an interpolation algorithm based on decoupled atomic norm minimization (DANM), which converts signal simple form. On basis, relaxation-based optimization formulated achieve DoA-range with enhanced DoFs. The reconstructed enables application existing subspace-based spectral methods. proposed DANM further reformulated as equivalent rank-minimization solved by cyclic rank minimization. This approach avoids approximation errors introduced in nuclear norm-based approach, thereby achieving superior root-mean-square error closer Cramer-Rao bound. effectiveness method confirmed theoretical analyses numerical simulations.