弹载SINS/GPS组合导航系统数据采集与同步设计

Data Acquisition and Synchronous Design in SINS/GPS Integrated Navigation System for Guidance Munitions

针对SINS/GPS组合导航系统来自两个导航系统的数据在时间上不同步导致在弹载高动态环境下导航精度降低的问题,设计了一种基于FPGA+DSP的小型嵌入式组合导航计算机平台.把GPS接收机提供的1PPS脉冲同时接入FPGA与DSP以提供时间基准,利用FPGA实现MIMU与GPS数据在整秒时刻的同步采集,利用DSP实现同步时间差的求取以及GPS数据的外推拟合,完成SINS与GPS数据在信息融合时刻的同步.时间同步过程简单,同步精度高.为了验证方法的有效性,进行了跑车试验,试验结果表明系统所采用的方法可以有效地提高高动态下组合导航系统的精度,比较未经过时间同步处理的导航结果,该方法在姿态角和速度精度上提高了约70%,位置精度提高了约50%,具有一定的工程应用价值.

For the SINS/GPS integrated navigation system,because the data from the two navigation systems are not synchronized in time,the navigation accuracy was reduced under the high dynamic environment of the missile.A small embedded integrated navigation computer platform based on FPGA+DSP was designed.The 1 PPS pulse provided by the GPS receiver was simultaneously connected to the FPGA and the DSP to provide a time reference.The FPGA was used to realize the synchronous acquisition of the MIMU and the GPS data at the second time,and the DSP was used to realize the calculation of the synchronization time difference and the extrapolation fitting of the GPS data,synchronization of SINS and GPS data at the moment of information fusion.The time synchronization process was simple and the synchronization accuracy was high.In order to verify the effectiveness of the method,the vehicle experiment was carried out on the system.The test results show that the method adopted by the system can effectively improve the accuracy of the combined navigation system under high dynamics,and compare the navigation results without time synchronization.The method is at the attitude angle and the speed accuracy is improved by about 70%,the positional accuracy is improved by about 50%,and it has certain engineering application value.