低波段天基雷达射频干扰机理及抑制方法

Radio Frequency Interference Mechanism and Suppression Methods for Low-Band Space-Borne Radar

天基合成孔径雷达(SAR)是一种重要的主动遥感设备,在测绘、目标警戒、资源探测等方面具有独特的全天时、全天候优势。但由于低波段电磁频谱异常拥挤复杂,也容易受到其他无线电设备的非蓄意射频干扰(RFI)。本文针对工作于P、L波段的天基SAR系统,分析其常见的地面射频干扰源及其干扰机理,并构建典型的窄带与宽带干扰模型,比较分析了频域陷波、最小均方(LMS)算法、自适应线谱增强(ALE)、特征子空间分解与时频滤波等多种干扰抑制算法,并在卫星实测数据的基础上进行仿真验证抑制宽带干扰的有效性。仿真结果表明:时频滤波算法抑制宽带干扰效果最好,造成的信号损失最小,能够为后续天基合成孔径雷达的抗干扰算法设计提供决策依据。

Space-borne synthetic aperture radar(SAR)is an important active remote sensing instrument,which has unique all-weather and all-time advantages in surveying and mapping,target detection,resource exploration,etc.However,due to the congestion of electromagnetic spectra in low band,it is also vulnerable to be affected by unintentional radio frequency interferences(RFIs)from other radio devices.In this paper,the common terrestrial interfering sources and the jamming mechanisms of space-borne SAR systems operating in P and L bands are analyzed.Typical narrowband and broadband jamming models are established.Several interference suppression algorithms such as the frequency-domain notch filtering algorithm,the least mean square(LMS)algorithm,the adaptive line enhancement(ALE)algorithm,the eigen-subspace decomposition algorithm,and the time-frequency filtering algorithm are comparatively analyzed,and the effectiveness of suppressing broadband interferences is verified by simulation based on the measured satellite data.The simulation results show that the time-frequency filtering algorithm has the best suppression effect on broadband interferences and the minimum signal distortion,which can provide decision-making basis for the subsequent anti-jamming algorithm design of future space-borne SAR.