Non-Synchronous Measurements of a Microphone Array at Coprime Positions

In this letter, an acoustic imaging method is proposed to improve conventional non-synchronous measurements (NSM) by carrying out the NSM at coprime positions (CP-NSM). The pattern of the NSM movement is guided by a set of coprime positions. A virtual domain signal is then constructed by vectorizing the covariance matrix of the NSM. Similarly, a virtual array is constructed using the Kronecker product of the Green's function of the CP-NSM. Therefore, the synthetic aperture of the proposed CP-NSM is first expanded by the NSM, and further enlarged by the virtual array. The simulation results demonstrate that the proposed CP-NSM achieves higher spatial resolution at lower frequencies and a lower signal-to-noise ratio than the conventional NSM.