Virtual wave beam forming method based on coprime arrays

Abstract

The invention discloses a virtual wave beam forming method based on coprime arrays. The method comprises the steps of: firstly, arranging a plurality of array elements to form the coprime arrays, and carrying out multi-snapshot sampling on incident signals of a plurality of non-relevant signal sources in different spatial directions; carrying out time averaging estimation on correlation function values different in correlation space; then based on corresponding relations between correlation spaces and coprime array difference cooperation array virtual array element positions, extracting the correlation function values having the continuous correlation spaces, and constructing equivalent single-snapshot signals of virtual array elements uniformly distributed in difference cooperation arrays; and finally, according to the position distribution of the uniformly distributed virtual array elements, designing weight vectors, and carrying out weighted superposition on the equivalent single-snapshot signals so as to obtain output wave beams. According to the invention, the characteristic that most virtual array elements are uniformly distributed in the difference cooperation arrays of the coprime arrays is utilized to solve the problems of an existing sparse subarray wave beam multiple multiplication method that sidelobe interference exists and the method is not suitable for a plurality of signal sources, the wave beam signal to noise ratio is effectively increased, and the noise resistance is improved.

Description

technical field [0001] The invention belongs to the technical field of array beamforming, and relates to a virtual beamforming method based on a coprime array. Background technique [0002] The coprime array is a new type of non-uniform sparse array proposed in 2010. It consists of two uniform sparse sub-arrays with a coprime relationship between array elements. Compared with traditional non-uniform arrays such as minimum redundancy matrix and nested array Sparse arrays and coprime arrays have outstanding advantages such as simple layout design of array elements and little influence of mutual coupling of array elements. [0003] Array signal processing has been widely used in radar, sonar, communication, seismic exploration and other fields. Its two main research directions are direction of arrival estimation and beamforming. The coprime array was first applied to the direction of arrival estimation of the space signal source, and the dimensionality of the correlation matri...

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Problems solved by technology

However, in this method, part of the grating lobes are retained and degenerated into side lobes when the sub-beams are multiplied and fused, causing obvious side-lobe interference. In addition, when there are multiple signal sources in the space, the grating lobes of the signal sources in the sub-beams will alias When the main lobe enters, the main lobe of the sub-beam is distorted or attenuated. Combined multiplication and fusion cause serious grating lobe residue and main lobe degradation, and the output beam is chaotic and cannot distinguish the directions of multiple signal sources.

Therefore, the existing beamforming methods based on coprime arrays have obvious defects such as sidelobe interference and not being suitable for multiple signal sources

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