Detection method of slow and weak target based on external radiation source radar

Abstract

The invention belongs to the technical field of radars, and discloses a slow-speed weak target detection method based on an external radiation source radar. The method comprises the steps that a receiving antenna is divided into m equidistant overlapping subarrays; sub-signals received by m equidistant overlapping subarrays and a reference signal received by a reference antenna are acquired; a first covariance matrix is calculated; eigen decomposition is carried out on the first covariance matrix to acquire eigenvalues and corresponding eigenvectors; the eigenvectors are orthogonalized; orthogonalized eigenvectors corresponding to M larger eigenvalues are used to construct an interference subspace; the summation signal of sub-signals is projected onto an orthogonal subspace of the interference subspace to acquire a target echo signal; distance-Doppler two-dimensional correlation is carried out on the reference signal and the target echo signal to acquire a correlation matrix; and constant false alarm detection is carried out on the correlation matrix to acquire the slow-speed weak target information. According to the invention, the detection signal-to-noise ratio of a target can be improved, and the slow-speed weak target is effectively detected.

Description

technical field [0001] The invention relates to the technical field of radar, in particular to a slow weak target detection method based on external radiation source radar. Background technique [0002] External radiation source radar means that it does not emit electromagnetic waves itself, but uses existing third-party radiation source signals (such as FM broadcast signals, analog TV signals, communication signals, etc.) as irradiation sources to illuminate targets and receive echo signals reflected by targets. Then filter the clutter in the echo signal to obtain the target echo, and use the radar system to detect, locate and track the target according to the target echo. Because the external radiation source radar itself does not radiate electromagnetic waves, it has good concealment and is difficult to be detected by the enemy's electronic reconnaissance equipment. It has low cost and simple structure, so it has attracted much attention. [0003] Due to the characterist...

AI Technical Summary

Problems solved by technology

However, in the case of strong direct wave and multipath interference, there is strong coherence between the target echo and the direct wave and multipath signal. If the existing orthogonal projection algorithm based on eigendecomposition is used to filter out the clutter , will cause the rank deficit of the signal covariance matrix, and then make the signal eigenvector diverge into the noise subspace, resulting in a decrease in the detection signal-to-noise ratio of the target, or even the situation where the target cannot be detected

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