采用改进型时频滤波的海杂波抑制方法

A Sea Clutter Suppression Method Using Improved Time-frequency Filtering Method

海洋环境下,海杂波具有明显的非平稳、非高斯特性,海杂波谱中心频率不固定、谱宽较宽,严重影响了雷达对海面目标的检测。传统的频域滤波器难以对复杂多变的海杂波进行有效抑制。本文通过分析海杂波的时频谱频率变化特征,定量计算各距离单元时频谱的中心频率平滑度,提出了采用基于时频谱能量分布的改进型时频滤波方法进行海杂波抑制。通过对实测海杂波数据的杂波抑制效果进行分析,验证了该算法能够有效滤除海杂波信号和保护低速目标信号能量,提高目标信杂噪比,对提升雷达检测能力具有重要的作用。

In the marine environment,the sea clutter has obvious non-stationary and non-Gaussian characteristics.The center frequency of the sea clutter spectrum is not fixed and the spectral width is wide,which seriously affects the radar’s detection of the sea surface target.Traditional frequency domain filters are difficult to suppress complex and varied sea clutter effectively.In this paper,by analyzing frequency variation characteristics of sea clutter,we calculate the center frequency smoothness of the spectrum at each distance unit quantitatively and propose an improved time-frequency filtering method based on time-frequency energy distribution for sea clutter.The frequency spectrum dimension of sea clutter is divided into a plurality of frequency intervals,and the frequency range of clutter is determined by determining the frequency interval with the largest energy occupation ratio,and the amplitude mean value of the interval is calculated as the filtering threshold value.Performing filtering performance analysis on actual sea clutter data,the results show that the proposed algorithm has better filtering performance than traditional algorithms and can be applied to clutter suppression under various sea conditions.It is verified that the algorithm can filter out sea clutter signals effectively and protect low-speed target signal energy,improve target signal-to-noise ratio,and play an important role in improving radar detection capability.