针对GPS L1C信号中CNAV-2电文的帧同步问题,提出了基于多重分形谱的帧同步算法。在对待同步序列进行固定长度拆分的基础上,通过计算各拆分序列的多重分形谱宽度值分布,实现电文数据的粗同步。利用电文数据的结构特点,结合BCH编码码字已知的条件,对粗同步序列进行码字匹配,并最终实现电文数据的准确同步。仿真实验表明,在误码率较高的条件下,拆分序列的多重分形谱宽度值依然存在周期性的峰值分布,文中算法具有较好的抗误码性能。

In order to solve the problem of frame synchronization of CNAV-2 message in GPS L1C signal, an algorithm for frame synchronization based on multi-fractal spectrum is proposed. Based on the fixed length splitting of the synchronization sequence, the coarse synchronization of the message data is realized by calculating the multifractal spectrum width distribution of each split sequence. According to the structure characteristics of the message data and the known condition of BCH code word, the coarse synchronization sequence is matched and the accurate synchronization of the message data is finally realized. Simulation results show that, under the condition of high bit error rate, the multifractal spectrum width of the split sequence still has periodic peak distribution, which shows that the algorithm has good error resistance performance.