Study on the problem of coherent source resolution with same frequency for the coprime array

Abstract

The coprime sensor array (CSA) can achieve the same resolution capability as an equally spaced half-wave array even using fewer array elements. For single-target, CSA can achieve good anti-grating lobe effect. When there are multiple coherent sources of the same frequency, there still are overlaps between the main lobes and grating lobes of the subarray from different sources, and between the grating lobes and grating lobes of different subarray. In some cases, the strong grating lobes can interfere discriminating the azimuth and quantity of targets. This paper focuses on the multi-targets discrimination problem of CSA for the same frequency coherent source. A processing algorithm of CSA coherent sources is presented. This method uses iterative processing methods to detect and remove strong targets one by one. Then, reconstruct the spatial spectrum of each single target. Finally, recombine the spatial spectrum by each single target spatial spectrum after sidelobe suppression processing. This method can well remove the grating lobe of multiple targets. It is also applicable to the situation when the grating lobe is higher than the weak target peak under strong and weak contrast conditions. The performance of the method was simulated and the results confirmed the feasibility of the method.