一种捷变调频斜率极性和限幅相结合的SAR抗干扰方法

SAR Anti-jamming Method Based on Jittering Slope Polarity of LFM and Thresholding

针对合成孔径雷达(SAR)系统面临的场景散射等干扰无法使用传统时、空、频域技术抑制的问题,提出了一种基于线性调频(LFM)信号调频斜率极性捷变和限幅过程相结合的抗干扰方法。该方法首先在慢时间域捷变雷达发射信号的调频斜率极性,其次在接收脉冲后首先对转发的干扰信号进行匹配、限幅,然后在逆滤波之后正常成像。仿真验证了捷变方法的抗干扰性能。

Corresponding to the problem of being unable to remove terrain scattered jamming from the domains of time, space and frequency, this paper proposes an anti-jamming method based on jittering slope polarity of Linear Frequency Modulated（LFM） signal and limiting processing. This method first jitters chirp rate polarity of LFM signal transmitted by the radar in slow-time domain, then does match-filters for the jamming signals hidden in the radar echoes, since jamming is more powerful than radar echo, the next process of limiting will lower the amplitude of jamming greatly, after limiting process, limited echoes are inversely match-filtered, so jamming and real radar echo are all back to the original time domain, then the next normal imaging process can be implemented which will also provide the real radar echo more gain than jamming, so SJR （Signal-to-Jammlng Ratio） is further enhanced. Simulation results testify the anti-jamming performance of the method.