基于分数阶傅里叶变换的GNSS接收机抗线性调频干扰技术研究

Research on LFM Interference Suppression Technology Based on Fractional Fourier Transform in GNSS Receiver

关键词:  全球导航卫星系统  分数阶傅里叶变换  连续线性调频干扰  干扰抑制

Key words:  GNSS  FRFT  Continuous LFM interference  Interference suppression

摘要:

研究了分数阶傅里叶变换(Fractional Fourier Transform，FRFT)抗线性调频（Linear Frequency Modulation，LFM）干扰技术，提出了一种基于FRFT域幅度一阶矩的逐精度求取最佳变换阶次的方法，并针对连续LFM干扰提出了一种求取最佳变换阶次的策略。同时针对全球导航卫星系统（Global Navigation Satellite System，GNSS）中的LFM干扰，对信号的预处理、阈值的自适应选取做了研究与分析，给出了相应的处理方法。仿真结果表明，该方法能够减少抗连续LFM干扰时求取最佳变换阶次的计算量，而且可以有效抑制GNSS接收机中的LFM干扰。

Abstract:

The linear frequency modulation (LFM) interference suppression technology based on the fractional Fourier transform (FRFT) is studied and a method of calculating the optimal transformation order of transformation by progressive grade of precision based on the first-order moment of the amplitude in the FRFT domain is proposed in this paper. At the same time, for the continuous LFM interference, a strategy of calculating the optimal transformation order of FRFT is proposed. In addition, for the LFM interference in GNSS receiver, signal preprocessing and adaptive threshold selection are studied and analyzed, and corresponding solutions are presented. The simulation results show that the method proposed in this paper can effectively reduce the calculation amount of getting the optimal transformation order of continuous LFM interference and suppress the LFM interference in GNSS receiver efficiently.