基于FRFT和相位差分法的LFM-BPSK复合信号识别

LFM-BPSK Hybrid Modulated Signal Recognition Based on FRFT and Phase Difference Arithmetic

雷达信号的脉内调制方式识别一直是电子对抗信息处理中的重要内容。线性调频-二相编码(LFM-BPSK)复合调制信号已被广泛应用,但是对LFM-BPSK复合信号有效识别的方法非常少。针对这一问题,提出了分数阶傅里叶变换和相位差分法相结合的算法。首先对信号进行分数阶傅里叶变换,在两种搜索尺度下,寻找模峰值点对应的变换阶数,根据变换阶数的不同判断信号中是否含有线性调频成分,再利用相位差分法,对瞬时相位进行提取,根据是否存在相位跳变信息,对LFM和LFM-BPSK信号进一步识别。仿真结果表明,该方法有一定的抗噪性和较高的识别率。

Radar signal pulse modulation recognition is an important part of electronic countermeasure information processing. LFM-BPSK hybrid modulation signal has been widely applied,but there are very few methods to identify this composite signals effectively. To solve this problem,a new algorithm combining FRFT and phase difference method is proposed. Firstly,the signal is carried out by fourier transform. Under the two search scales,the transformation order of the peak value is found,and the linear frequency modulation component is determined according to the different order of transformation. Secondly,the phase difference method is used to extract the instantaneous phase,and the LFM and LFMBPSK signals are identified based on the presence of phase discontinuity. Simulation results show that the proposed method has certain noise immunity and high recognition rate.