Improved subspace sea clutter suppression method based on local correlation

A correlation, sea clutter technology, applied in radio wave measurement systems, radio wave reflection/re-radiation, utilization of re-radiation, etc., can solve problems such as inaccurate covariance estimation, small sample size, and inability to accurately estimate , to improve the robustness, improve the signal-to-noise ratio, and achieve good results

Inactive Publication Date: 2014-11-19
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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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...

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  • Improved subspace sea clutter suppression method based on local correlation
  • Improved subspace sea clutter suppression method based on local correlation
  • Improved subspace sea clutter suppression method based on local correlation

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Embodiment Construction

[0041] The technical scheme of the present invention is described in detail below in conjunction with accompanying drawing:

[0042] figure 1 It can reveal the position of the sea clutter suppression module in the high-frequency ground wave radar ship target detection signal processing flow, and the operation of the sea clutter suppression processing after pulse compression in the range direction and digital beamforming in the azimuth direction. A frame of data (also referred to as a dwell time) is defined as a three-dimensional data block of fast time-slow time-channel. The number of fast time samples corresponds to the number of range units, the number of slow time samples corresponds to the number of pulses coherently accumulated by the radar, and the number of channels is the number of radar receiving antennas. The sea clutter suppression method proposed by the present invention is a sea clutter suppression method in the time domain, that is, the sea clutter is suppressed...

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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...

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Application Information

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IPC IPC(8): G01S7/36
CPCG01S7/414G01S7/2927G01S2013/0227
Inventor 赵慧俊周涛张弓徐坤胡文王鑫海万明雪张璐季秀霞
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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