低速非相干扩频信号的快速同步方法研究

Research on Fast Synchronization Methods of Low-symbol-rate Non-coherent DSSS Signals

为了降低低速非相干扩频信号的同步时间,提出了一种分阶段的同步方法。该方法将整个同步过程分为伪码搜索与捕获、频率细估计、伪码跟踪、定时和载波相位跟踪几个阶段。其中前2个阶段采取了并行处理方法,在降低处理时间的同时提高了可接收的信号动态范围;后续各个阶段的处理充分利用了前面处理已经获知的同步信息,进一步减少了信号的同步时间。仿真和FPGA实测结果表明,该同步方法可实现低速非相干扩频信号的快速同步,与传统同步方法相比,同步速度可提高一个数量级。

A synchronization method with several stages is proposed to reduce synchronization time of low-symbol-rate non- coherent DSSS signals.The synchronization process consists of following stages：search and acquisition of PN code,carrier frequency fine estimation,PN code tracking, timing and carrier phase tracking. In this method, the first two stages adopt parallel processing, which reduces process time and expands the dynamic range of receive signals. And, the following stages fully use the synchronization information already obtained,which reduces the synchronization time further.Simulation results and FPGA measure results indicate that this synchronization method can realize fast synchronization of low-symbol-rate non-coherent DSSS signals, synchronization speed can be improved one order compared with the traditional synchronization methods.