针对伪码调频连续波信号分析问题,提出了基于分数阶Fourier变换(FRFT)和累加积分的参数估计方法。首先对PRBC-LFM信号平方处理,利用FRFT估计线性调频参数并重构线性调频信号,将原信号与重构信号共轭相乘去除载波,使原信号变成二相编码基带信号,最后利用基带信号累加积分的拐点信息估计子码宽度,同时根据累加积分的变化趋势实现对二相编码信号编码规律的识别。与现有方法相比,该方法在信噪比为-4dB时仍具有较好的估计效果。

In view of PRBC-LFM signal analysis, a fractional Fourier transform and accumulative integral based parameter estimation algorithm was proposed. Firstly, the square of received signal was attained to eliminate the effect of PRBC in analysis. Then the FRFT was used to estimate LFM modulation parameter which can also be adopted to reconstruct the LFM signal. The original signal was multiplied with the conjugated reconstruction LFM signal to remove carrier wave and get baseband signal PRBC. Finally, the code width and code sequence of PRBC was extracted using the inflexion point information and the change trend of accumulative integral. Compared with present methods, the proposed algorithm still take on good estimation result even in SNR = -4dB.