舰船轴频电场信号特征提取与检测方法

The Feature Extraction and Detection for Shaft-rate Electric Field of a Ship

为了能够在低信噪比的条件下提高目标的检测概率,降低目标的虚警概率,提出了一种舰船轴频电场信号特征提取与检测方法。根据舰船螺旋桨转速与轴频对应关系确定了特征频段,将该频段平均功率谱值作为特征量。根据环境的变化,设置了具有自适应功能的动态阈值。通过设定较小的阈值因子,放宽对疑似目标点的判决条件。在特征频段内对信号进行线谱检测,剔除掉连续谱以及不符合线谱条件的频率点。最终经过线谱倍频判断和稳定性判断确认目标是否存在。对实船轴频电场信号进行了特征提取和检测,在不同信噪比的条件下均成功检测到了目标。

Shaft-rate electric field of a ship is one of the important target recognition features. In the course of the real-time detection,the electric signature of the ship is easily influenced by the noise,which brings the difficulty to the detection. In order to detect a target in strong noise,a method of extracting and detecting the signal features of shaft-rate electric field is proposed. The characteristic frequency band is choosen,the mean value of the power spectrum in the band is calculated as a characteristic parameter,and the dynamic threshold is set. The dubious target is confirmed with a small threshold. The line spectrum is recognized in order to rule out continuous spectra and the unacceptable frequency points.Finally,it is judged whether the target exists or not based on line-spectrum double-frequency and stability criterion. A real ship is detected in the condition of the different SNRs. The practical results show that the method is effective.