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

TL;DR

This paper introduces a novel joint DoA and range estimation method using a space-frequency virtual coarray with coprime arrays, employing decoupled atomic norm minimization to improve accuracy and computational efficiency.

Contribution

It proposes a decoupled atomic norm minimization algorithm for joint DoA-range estimation that overcomes computational challenges and enhances degrees-of-freedom.

Findings

Achieves near Cramer-Rao bound estimation accuracy

Reduces computational complexity compared to traditional methods

Demonstrates superior performance through simulations and analysis

Abstract

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