Summary: | Recently, coprime array has been a popular research field in the application of direction-of-arrival estimation. Compared with uniform linear array, coprime array can be used to expand array aperture with fewer sensors, and it also has a nice direction-of-arrival estimation performance. According to coprime property, the direction of arrival can be obtained by intersecting the candidate estimation sets from several subarrays. However, when the directions of multiple sources meet a particular relation, the unambiguous phase cannot be unwrapped through the coprime array. In this article, a multi-coprime array is proposed to address the problem, utilizing about half number of array elements and reducing hardware complexity compared with uniform linear array. Then, a low-complexity beamforming interferometry algorithm via multi-coprime array is proposed to reduce computational complexity. Numerical results, including simulation and actual data processing, are provided to indicate that the processing on multi-coprime array can successfully resolve phase ambiguity. Specially, when signal-to-noise ratio exceeds about −4 dB and the element number of subarray in multi-coprime array exceeds 15 for the array geometry in this article, the proposed method achieves close estimation performance with fewer sensors compared with uniform linear array.
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