现有组合导航系统刚上电时,系统无时间信息,只有获得全球导航卫星系统(GNSS)时间信息后,组合导航系统才会有时间信息。本文为组合导航系统增加时间保持电路,通过FPGA完成时间保持电路的时间初始化、时间保持、时间修正。系统下电时,使用内部电池对时间保持电路进行供电,实现组合导航系统的时间保持功能。测试结果显示,时间保持电路满足使用精度要求。

When the existing integrated navigation system is powered on,the system has no time information.The integrated navigation system will have time information only when the global navigation satellite system (GNSS) time information is obtained.This paper adds a time holding circuit to the integrated navigation system,and completes the time initialization,time holding and time correction of the time holding circuit through FPGA.When the system is powered off,the internal battery is used to supply power to the time holding circuit to realize the time holding function of the integrated navigation system.The test results show that the time holding circuit meets the requirements of time accuracy.