蔚娜　李雪　李铁成

(中国电波传播研究所,青岛 266107)



基于特征分解的多模杂波抑制方法

蔚娜李雪李铁成

(中国电波传播研究所,青岛 266107)

摘要电离层对天波超视距雷达回波信号的污染严重制约了雷达对慢速目标的检测,相位扰动与多模传播共存时,更是加重了回波杂波谱的展宽. 针对这一情况,文中提出了基于特征分解的多模杂波抑制方法,根据不同群距离单元上回波信号的相关性来选择群距离单元构造协方差矩阵,通过一个模板滤波器对回波信号滑动滤波来确定回波信号模式个数,从而可通过对协方差矩阵的特征分解来确定目标信号和噪声子空间,继而完成杂波的抑制. 该方法实现简单,适合工程应用,并且对实测数据的处理结果证实了该方法的有效性.

关键词天波超视距雷达;相位扰动;多模;杂波抑制

DOI10.13443/j.cjors.2015021301

An eigenvalue decomposition based method for suppressing multi-mode clutter

WEI NaLI XueLI Tiecheng

(ChinaResearchInstituteofRadiowavePropagation,Qingdao266107,China)

AbstractThe detection of slow-moving target is seriously hampered by ionospheric contamination in the over-the-horizon radar(OTHR). The clutter spectrum is broadened worse when the phase disturbance and multi-mode propagation coexist. In this paper, a method for suppressing multi-mode clutter based on eigenvalue decomposition is presented to solve the problem mentioned above. The echo signals of some group-distance cells selected in according to the correlation among different cells are used to construct the covariance matrix, and the mode number of echo signal is obtained through sliding filtering using a template filter. After that, the target signal and noise subspace is determined, and then, the multi-mode clutter is suppressed. The method is easy to implement, thus suitable for engineering applications. The processing resuleness of the measured data show the effectiveness of the proposed method.

Keywordsover-the-horizon radar; phase disturbance; multi-mode; clutter suppressing

引言

天波超视距雷达(Over-The-Horizon Radar,OTHR)依靠电离层对短波段(3～30 MHz)电波的折射、反射实现远距离目标探测. 然而,由于电离层的分层结构及时变非平稳特性会对在其内往返传播的雷达信号造成污染,使雷达信号回波谱图产生多普勒频移和展宽,这严重制约了雷达对慢速目标(如舰船)的检测.

电离层对雷达回波信号的污染机制可以归纳为以下三种情况: ① 相位扰动; ② 多模传播; ③ 相位扰动与多模传播共存.对于只存在相位扰动时,目前常用的处理方法主要包括:① 估计信号的瞬时频率,重构信号相位,继而计算相位污染校正函数,例如最……