DOA estimation method for mixed signal under symmetric uniform linear array

Abstract

The invention discloses a DOA estimation method for a mixed signal under a symmetric uniform linear array. The DOA estimation method comprises the following steps of: acquiring the mixed signal at a moment t by adopting a sensor array, calculating by utilizing an ESPRIT algorithm to obtain a DOA estimation matrix, and performing characteristic decomposition on the DOA estimation matrix; estimating an angle of arrival of an independent signal transmitted in the independent signal source according to a decomposition result; and acquiring information of a coherent signal source, constructing a matrix which retains the information of the coherent signal source, solving the matrix which retains the information of the coherent signal source through an improved spatial smoothing algorithm to obtain a covariance matrix after complete decoherence, acquiring a rotation operator according to the covariance matrix, and solving the rotation operator by utilizing a TLS-ESPRIT algorithm, so as to obtain an angle of arrival of a coherent signal. According to the DOA estimation method, the angles of arrival of the independent signal and the coherent signal are respectively estimated, so that the algorithm precision and the resolution of similar angles are improved, and the loss of array apertures is further reduced.

Description

technical field [0001] The invention belongs to the technical field of signal processing, and relates to a DOA estimation method of a mixed signal under a symmetrical uniform linear array. Background technique [0002] Traditional subspace algorithms or algorithms based on rotation invariance can directly estimate the angle of arrival of incoherent signals. However, in the real environment, multiple coherent incident signals are generated due to the multipath effect caused by the reflection of mountains and urban buildings. In this case, there is a rank deficit in the source covariance matrix, and the traditional MUSIC method or ESPRIT method cannot be directly used. To estimate the DOA of the signal, it is necessary to perform smoothing and decorrelation and then use the traditional algorithm to estimate the DOA of the signal. Early scholars proposed a spatial smoothing preprocessing method, such as the forward spatial smoothing algorithm, but this algorithm requires a hig...

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Problems solved by technology

[0003] However, when independent signals and coherent signals exist at the same time, the above spatial smoothing algorithms estimate the angles of arrival of all mixed signals at one time, which does not meet the actual needs and reduces the utilization of the array elements.

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