Improved subspace sea clutter suppression method based on local correlation

Abstract

The invention discloses an improved subspace sea clutter suppression method based on local correlation. Suppression of sea clutter can improve the signal to clutter ratio of targets and is conductive to improving the vessel target detection performance of high frequency surface wave radar (HFSWR). The original subspace method leads to identical covariance matrix of all distance unit structures during sea clutter suppression, so that a poor suppression effect caused by inaccurate clutter space estimation is brought about, which is reflected on the distance Doppler spectrum that the suppression effects of sea clutter in different distances are similar. According to the invention, the related coefficient between a distance unit to be detected and adjacent distance units is calculated, the reference unit of the covariance matrix is determined and formed in a self-adaptive manner, the formed covariance matrix is subjected to singular value decomposition (SVD) to obtain subspaces of the sea clutter, and finally, suppression is realized. The method can simultaneously suppress first-order and high-order sea clutter, improves the signal to clutter ratio of the targets and has a relatively ideal suppression effect on all distance units.

Description

Technical field: [0001] The invention relates to a sea clutter suppression method for high-frequency ground wave radar, in particular to an improved subspace sea clutter suppression method based on local correlation. Background technique: [0002] High-frequency ground wave radar works in the 3-30MHz frequency band and is a kind of over-the-horizon radar. It uses the characteristics of small diffraction and propagation loss of vertically polarized electromagnetic waves along the coastal surface, and can realize the analysis of ocean dynamics parameters and slow-moving targets on the sea. And the monitoring and positioning of low-altitude aircraft have been widely used in military and civilian fields in recent years. [0003] The echo situation of high-frequency ground wave radar is complex, in addition to radio frequency interference, transient interference and ionospheric interference, it also includes strong sea clutter. Sea clutter energy is mainly concentrated at two fi...

AI Technical Summary

Problems solved by technology

If the number of reference units is too large, the spatial correlation of sea clutter is weakened, and the covariance estimation is inaccurate. Using the same standard for suppression in a large area does not conform to the characteristics of the spatial distribution of sea clutter; the number of reference units If the value is too small, the sample size will be too small to make an accurate estimate

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