多模导航模拟器时间同步控制系统设计与实现

Design and implementation of time synchronization control system of multi-mode GNSS signal simulator

摘要:

在多模导航模拟器的设计过程中,由于需要模拟的导航信号频点较多,使得如何修正由于多个上位机程序启动时间差异导致的数据包不同步,以及如何控制不同中频板卡同步启动以产生时间同步的中频信号成为了关键问题。针对这两个问题,设计并实现了一种应用于基于软件无线电体系架构多模导航信号模拟器的时间同步控制系统。该系统通过由系统计时板对外设板卡同步触发启动控制,驱动软件与外设板卡1s时隙同步控制,以及驱动软件向外设板卡传输数据包的同步控制,实现对各系统频点的时间同步控制,能够支持多模导航信号模拟器长时间持续稳定的工作,具有各系统频点时间同步精度高和系统复杂度低等优点。通过联合定位测试结果表明,采用本控制系统的多模导航模拟器的各系统频点的输出信号是时间同步的。

Abstract:

Because of the big demand of navigation signals which need to be simulated, in the process of the design of multi-mode GNSS signal simulator, how to rectify the unsynchronized packets caused by the difference of several applications’ boot time and how to generate time-synchronized intermediate-frequency signal by controlling different IF boards become the key problems. Aiming at these problems, an algorithm for the time synchronization control based on GNSS signal simulator was proposed, which can applied to the GNSS signal simulator which adopt the software radio system architecture. Meantime, the control of generating synchronous IF signal by the peripheral boards by the system timing board, the control of 1s slot synchronization of driver software and peripheral boards and the control of packet synchronization that diver software transmitted to the peripheral boards were used to carry out the time synchronization control of different satellite navigation system. In addition, the proposed algorithm could support the continuant and stable work of multi-mode GNSS signal simulator for a long time, and exhibit the advantages of high time synchronization precision and low system complexity. By the multi-satellite joint location test, it is proved that the output signal of multi-mode GNSS signal simulator is time synchronization.