为了说明高动态环境中时间同步对于组合导航系统的重要性,在Kalman滤波方程的基础上,推导了时间同步误差与Kalman滤波结果之间的定性关系。提出一种利用GPS接收机中1PPS(Pulse Per Second)信号作为同步标签的时间同步方法,将IMU中的数据加上精确的时间标签,从而达到时间同步的目的。全部时间同步功能由FPGA实现,利用Verilog HDL语言进行开发,整体硬件结构简单而且适用范围广。试验结果显示了这种时间同步设计可以明显减小滤波结果的估计误差,有效的提高了组合导航系统的定位精度。
The relation between time delay and data fusion performance is analyzed in the integrated GPS/ INS system on the basis of Kalman filter algorithm,and the importance of time synchronizing for the integrated GPS/INS system in high dynamic maneuver is discussed. A new time synchronization solution using 1PPS(Pulse Per Second)signal from a GPS receiver as the common synchronization reference signal is pro-posed. The method is implemented on a Field Programmable Gate Array(FPGA)development board with Verilog HDL programming language,and the design has a simple hardware structure and wide applicability. The result denotes that the proposed time synchronizer design has the capability of reducing the error of Kalman filter and enhancing the accuracy of positioning.