Abstract: Firstly,the limitations and advantages of various existing time synchronization solutions of GPS/INS are investigated in this paper.From the angle of modularity,a flexible low-cost time synchronization solution using a DAQ card and Labview software of NI in the way of both hardware and software is proposed and implemented.The test shows that a synchronization accuracy of 5 ms was achieved when the test system was applied to synchronize a low-grade micro-electromechanical inertial measurement unit(IMU),which only has an RS-232 data output interface.