伪卫星网络时频同步系统设计与实现

摘要

为实现伪卫星自组织网络高精度时频同步,设计了一种应用SCPA结构的伪卫星时频同步系统.该系统以FPGA和DSP作为核心基带处理芯片,集成了高速数模转换与模数转换电路以及上下变频电路.详细介绍了伪卫星双向伪距测量技术和时频同步设计方案及实现.系统测试结果表明,伪卫星系统星间载波相位同步误差小于0.1 Hz,时间同步精度优于2 ns,可达到伪卫星自组织网络系统定位精度与授时精度要求.%In order to achieve high precision of the time and frequency synchronization of pseudolite automatic network,a pseudolite time and frequency synchronization system using the structure of Self-Calibrating Pseudolite Array(SCPA) is designed.The system takes FPGA+DSP as the core processor,and integrates high-speed A/D,D/A conversion circuit and up and down converter circuit.The design and implementation of pseudolite two-way pseudo distance measurement technology and the time and frequency synchronization scheme are introduced in detail.The test results show that the phase synchronization error of cartier phase is less than 0.1 Hz and the time synchronization accuracy is better than 2 ns,which provids a significant guarantee for the positioning and timing accuracy of the pseudolite automatic system.