scholarly journals A Generalized Oblique Projection Filter with Flexible Parameter for Interference Suppression

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Yi-ming Wang ◽  
Xing-peng Mao ◽  
Hong Hong ◽  
Jie Zhang ◽  
Yu-mei Cui
Keyword(s):  
High Frequency ◽  
Array Signal Processing ◽  
Interference Suppression ◽  
Minimum Variance ◽  
Clutter Suppression ◽  
Oblique Projection ◽  
Wave Radar ◽  
Minimum Variance Distortionless Response ◽  
Polarization Filtering ◽  
Better Than

A generalized oblique projection (GOP) with an adjustable parameter defined as interference suppression cost (ISC) is proposed. Therefore, an optional optimized signal to interference-plus-noise ratio (SINR) and user controlled actions on the interference filtering are presented in this GOP framework. Theoretical analysis and numerical simulation demonstrate that when the ISC is derived from minimum variance distortionless response (MVDR) algorithm, the SINR performance of GOP filter is better than both MVDR and oblique projection (OP) filters. Further, an application of GOP filter in ionospheric clutter cancellation in a high frequency surface wave radar (HFSWR) system is given. The ISC is designed specifically to introduce an extra coherent loss to the clutters and a satisfying clutter suppression result is achieved. Besides the examples given, more designs of GOP filter can be inspired by the flexibility of ISC. As a generalized form of OP filter, GOP filter expands the connotation of oblique projection based technique and could be used in spatial filtering, polarization filtering, and other array signal processing applications.

Oblique projection polarisation filtering for interference suppression in high-frequency surface wave radar

2012 ◽  
Vol 6 (2) ◽  
pp. 71 ◽  
Author(s):  
X.-P. Mao ◽  
A.-J. Liu ◽  
H.-J. Hou ◽  
H. Hong ◽  
R. Guo ◽  
...  
Keyword(s):  
Surface Wave ◽  
High Frequency ◽  
Interference Suppression ◽  
Oblique Projection ◽  
Wave Radar

scholarly journals A Single-Dataset-Based Pre-Processing Joint Domain Localized Algorithm for Clutter-Suppression in Shipborne High-Frequency Surface-Wave Radar

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3773
Author(s):  
Liang Guo ◽  
Xin Zhang ◽  
Di Yao ◽  
Qiang Yang ◽  
Yang Bai ◽  
...  
Keyword(s):  
Surface Wave ◽  
High Frequency ◽  
Secondary Data ◽  
Real Data ◽  
Training Sample ◽  
Clutter Suppression ◽  
Low Velocity ◽  
Unscented Transformation ◽  
Wave Radar ◽  
Suppression Method

Due to the motion of the platform, the spectrum of first-order sea clutter will widen and mask low-velocity targets such as ships in shipborne high-frequency surface-wave radar (HFSWR). Limited by the quantity of qualified training samples, the performance of the generally used clutter-suppression method, space–time adaptive processing (STAP) degrades in shipborne HFSWR. To deal with this problem, an innovative training sample acquisition method is proposed, in the area of joint domain localized (JDL) reduced-rank STAP. In this clutter-suppression method, based on a single range of cell data, the unscented transformation is introduced as a preprocessing step to obtain adequate homogeneous secondary data and roughly estimated clutter covariance matrix (CCM). The accurate CCM is calculated by integrating the approximate CCM of different range of cells. Compared with existing clutter-suppression algorithms for shipborne HFSWR, the proposed approach has a better signal-to-clutter-plus-noise ratio (SCNR) improvement tested by real data.

scholarly journals Research on Polarization Cancellation of Nonstationary Ionosphere Clutter in HF Radar System

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xingpeng Mao ◽  
Hong Hong ◽  
Weibo Deng ◽  
Yongtan Liu
Keyword(s):  
Surface Wave ◽  
Time Domain ◽  
High Frequency ◽  
Interference Cancellation ◽  
Radar System ◽  
Experimental Results ◽  
Hf Radar ◽  
Oblique Projection ◽  
Polarization Filter ◽  
Wave Radar

Oblique projection polarization filter (OPPF) can be applied as an effective approach for interference cancellation in high-frequency surface wave radar (HFSWR) and other systems. In order to suppress the nonstationary ionosphere clutter further, a novel OPPF based clutter suppressing scheme is proposed in this paper. The polarization and nonstationary characteristic of the clutter are taken into account in the algorithms referred to as range-Doppler domain polarization suppression (RDDPS) and the range-time domain polarization suppression (RTDPS) method, respectively. The RDDPS is designed for weak ionosphere clutter and implemented in the range-Doppler domain directly, whereas the RTDPS algorithm is designed to suppress the powerful ionosphere clutter with a multisegment estimation and suppression scheme. About 15–23 dB signal to interference ratio (SIR) improvement can be excepted when using the proposed method, whereas the targets can be more easily detected in the range-Doppler map. Experimental results demonstrate that the scheme proposed is effective for nonstationary ionosphere clutter and is proven to be a practical interference cancellation technique for HFSWR.

Diagonal rejection-based minimum variance distortionless response for fiber underwater acoustic array

2017 ◽  
Vol 31 (19-21) ◽  
pp. 1740065
Author(s):  
Yang Chen ◽  
Ling Zou ◽  
Bin Zhou
Keyword(s):  
Covariance Matrix ◽  
Array Signal Processing ◽  
Spatial Filter ◽  
Minimum Variance ◽  
Observation Time ◽  
Small Aperture ◽  
Underwater Acoustic ◽  
Low Snr ◽  
Minimum Variance Distortionless Response ◽  
Acoustic Array

The high mounting precision of the fiber underwater acoustic array leads to an array manifold without perturbation. Besides, the targets are either static or slowly moving in azimuth in underwater acoustic array signal processing. Therefore, the covariance matrix can be estimated accurately by prolonging the observation time. However, this processing is limited to poor bearing resolution due to small aperture, low SNR and strong interferences. In this paper, diagonal rejection (DR) technology for Minimum Variance Distortionless Response (MVDR) was developed to enhance the resolution performance. The core idea of DR is rejecting the main diagonal elements of the covariance matrix to improve the output signal to interference and noise ratio (SINR). The definition of SINR here implicitly assumes independence between the spatial filter and the received observations at which the SINR is measured. The power of noise converges on the diagonal line in the covariance matrix and then it is integrated into the output beams. With the diagonal noise rejected by a factor smaller than 1, the array weights of MVDR will concentrate on interference suppression, leading to a better resolution capability. The algorithm was theoretically proved with optimal rejecting coefficient derived under both infinite and finite snapshots scenarios. Numerical simulations were conducted with an example of a linear array with eight elements half-wavelength spaced. Both resolution and Direction-of-Arrival (DOA) performances of MVDR and DR-based MVDR (DR–MVDR) were compared under different SNR and snapshot numbers. A conclusion can be drawn that with the covariance matrix accurately estimated, DR–MVDR can provide a lower sidelobe output level and a better bearing resolution capacity than MVDR without harming the DOA performance.

Configuration of Random Transducer Array in Irregular Region Based on Delaunay Triangulation

2010 ◽  
Vol 29-32 ◽  
pp. 1085-1090
Author(s):  
Shi Lin Wu ◽  
Qi Zhang ◽  
Zhi Ping Huang
Keyword(s):  
Delaunay Triangulation ◽  
Linear Array ◽  
Minimum Variance ◽  
Uniform Linear Array ◽  
Transducer Array ◽  
Irregular Region ◽  
Random Array ◽  
Minimum Variance Distortionless Response ◽  
Uniform Plane ◽  
Better Than

To realize the configuration of a cymbal transducer array in an irregular region, Delaunay triangulation is adopted to mesh the irregular region and the vertices of the Delaunay triangular mesh are regarded as the positions of the array elements. In this way, a random array of cymbal transducers is formed. Minimum Variance Distortionless Response (MVDR) beamformer is used to optimize the beam of the random array, and the directivity simulation is carried out in MATLAB. The results show that the directivity of the random array within the irregular region is better than that of the uniform linear array and that of the uniform plane array configured in the same region.

Cascaded method for ionospheric decontamination and sea clutter suppression for high‐frequency hybrid sky‐surface wave radar

2015 ◽  
Vol 9 (7) ◽  
pp. 562-571 ◽  
Author(s):  
Yajun Li ◽  
Yinsheng Wei ◽  
Yongpeng Zhu ◽  
Zhuoqun Wang ◽  
Rongqing Xu
Keyword(s):  
Surface Wave ◽  
High Frequency ◽  
Clutter Suppression ◽  
Sea Clutter ◽  
Wave Radar
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