卫星信道下低速扩频信号的快速同步

Fast synchronization of low-symbol-rate DS-SS signal in satellite channel

提出一种适合于卫星信道下低速扩频信号的快速同步方案。在高速时钟的驱动下,利用抽头数远小于扩频码长的匹配滤波器实现扩频信号的快速捕获;扩频码同步后先利用部分相关值对大载波频差进行初步估计,估计范围可接近符号率;然后再利用全相关值对剩余小频差进行精确的估计;最后利用锁相环实现载波的跟踪。计算结果和仿真结果表明,该方案是切实可行的。

A fast synchronization scheme for low-symbol-rate DS-SS signal in satellite channel is proposed. Driven by high rate clock, a matching filter whose coefficients are rather fewer than the PN code length is used for fast acquisition of the received DS-SS signal. After code synchronization is obtained, part correlation results are firstly used to estimate the carrier offset, which could be as large as the symbol rate, then total correlation results are used to estimate the left small carrier offset accurately, and at last, phase-lock-loop is used for carrier tracking. Calculation and simulation results show that the method proposed is feasible.