Off-Grid Direction-of-Arrival Estimation Using Coprime Array Interpolation

Chengwei Zhou, Yujie Gu, Zhiguo Shi, Yimin D. Zhang

Research output: Contribution to journalArticlepeer-review

176 Scopus citations


In this letter, we propose a coprime array interpolation approach to provide an off-grid direction-of-arrival (DOA) estimation. Through array interpolation, a uniform linear array (ULA) with the same aperture is generated from the deterministic non-uniform coprime array. Taking the observed correlations calculated from the signals received at the coprime array, a gridless convex optimization problem is formulated to recover all the rows and columns of the unknown correlation matrix entries corresponding to the interpolated sensors. The optimized Hermitian positive semidefinite Toeplitz matrix functions as the covariance matrix of the interpolated ULA, which enables to resolve off-grid sources. Simulation results demonstrate that the proposed array interpolation-based DOA estimation algorithm achieves improved performance as compared to existing coarray-based DOA estimation algorithms in terms of the number of achievable degrees-of-freedom and estimation accuracy.

Original languageEnglish
Article number8474369
Pages (from-to)1710-1714
Number of pages5
JournalIEEE Signal Processing Letters
Issue number11
StatePublished - Nov 2018
Externally publishedYes

Bibliographical note

Funding Information:
Manuscript received July 24, 2018; revised August 28, 2018; accepted September 21, 2018. Date of publication September 27, 2018; date of current version October 3, 2018. The work of C. Zhou and Z. Shi was supported in part by National Natural Science Foundation of China under Grant 61772467, in part by Zhejiang Provincial Natural Science Foundation of China under LR16F010002, in part by 973 Project 2015CB352503, and in part by the Fundamental Research Funds for Central Universities under Grant 2017XZZX009-01. The associate editor coordinating the review of this manuscript and approving it for publication was Prof. Jun Liu. (Corresponding author: Yujie Gu.) C. Zhou and Z. Shi are with the State Key Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou 310027, China (e-mail:,;

Publisher Copyright:
© 2018 IEEE.


  • Array interpolation
  • coprime array
  • direction-of-arrival estimation
  • matrix recovery
  • off-grid


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