Modified Eigensubspace-based Approach for Radio-frequency Interference Suppression of SAR Image
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摘要: 射频干扰(the Radio Frequency Interference, RFI)会对有用信号产生不利影响,进而严重影响成像质量。该文提出了一种改进的基于特征子空间的合成孔径雷达(Synthetic Aperture Radar, SAR)图像射频干扰抑制算法。相比传统算法,所提算法增加了专门用于射频干扰检测的预处理模块。在预处理阶段,分别在频域和时域对干扰所在的数据区域进行检测。在后处理阶段,只对检测到干扰的数据区域进行基于特征子空间的干扰抑制。相比传统算法,所提算法在保持图像细部结构方面效果更好,且避免了时域逐脉冲干扰抑制带来的巨大运算量,运算效率大幅提高。Abstract: Radio-Frequency Interference (RFI) adversely affects useful signals, thereby seriously affecting image quality. In this study, a modified eigensubspace-based approach for radio-frequency interference suppression of Synthetic Aperture Radar (SAR) images is proposed. In the preprocessing stage of our proposed algorithm, RFI detection is conducted in both the frequency and time domains. Subsequently, we can only deal with the data containing the RFI via the traditional eigensubspace-based approach. Compared with the traditional eigensubspace-based approach, our proposed algorithm can function more efficiently and effectively.
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图 2 距离向频谱图
Figure 2. Average range direction spectrum of Fig. 1
表 1 仿真实验的主要系统参数
Table 1. Main system parameters for experiment
参数 数值 雷达工作频率(GHz) 1.3 景中心斜距(km) 20 雷达有效速度(m/s) 150 波束斜视角 正侧视 发射脉冲时宽(μs) 2.5 距离向带宽(MHz) 50 距离向采样频率(MHz) 70 天线长度(孔径)(m) 3.75 方位向采样率(PRF)(Hz) 112 表 2 距离向/方位向关键指标的仿真实验结果(dB)
Table 2. Simulation results of key indicators in range /azimuth direction (dB)
方法 PSLR(峰值旁瓣比) ISLR(积分旁瓣比) 传统方法 –11.3740/–13.2009 –8.2197/–10.0441 改进方法 –12.9144/–13.2255 –9.9132/–10.1378 表 3 机载实验系统的主要系统参数
Table 3. Main system parameters for experiment
参数 数值 雷达工作频率(GHz) 1.3 景中心斜距(km) 15.883 雷达有效速度(m/s) 130.099 波束斜视角 正侧视 发射脉冲时宽(μs) 10.4 距离向带宽(MHz) 210 距离向采样频率(MHz) 266.667 天线长度(孔径)(m) 1.36 方位向采样率(PRF)(Hz) 899.5393 -
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