基于MEMS-IMU辅助的高动态GPS选星方法设计

一般的GPS选星方法通过搜索选取使几何精度衰减因子最小的4颗卫星,对于高动态应用特别是在水平姿态角较大的情况下,传统的选星方法存在许多局限性。针对低成本的MEMS-IMU/GPS组合导航系统,提出了基于MEMS-IMU辅助的GPS选星方法;针对高动态载体姿态变化较大的问题,采用MEMS-IMU输出的高速率姿态信息压缩卫星搜索范围,通过选取不超过6颗可见卫星来降低几何精度衰减因子,从而提高定位性能。使用半实物仿真数据,验证了所提出的方法。测试结果表明,与传统的选星方法相比,基于MEMS-IMU辅助的GPS选星方法在飞机高动态大机动条件下,优化了卫星星座,具有精度高、计算量低、可靠性高等优点。

Algorithm design for selecting satellite in MEMS-IMU-aided high dynamic GPS

Traditional GPS satellite selection algorithm uses only 4 satellites with minimal Geometric Dilution of Precision(GDOP)and doesn't work well in high dynamic conditions.In view of the application of low-cost MEMS-IMU/GPS integrated navigation system,a MEMS-IMU aided GPS satellite selection algorithm is proposed. To overcome the fast changing of level attitude,the high rate attitude information output by MEMS-IMU was used to compress satellite's searching range.By selecting less than 6 visible satellites(not only 4 satellites normally)to decrease the GDOP value and improve the positioning accuracy.The hardware-in-the-loop simulation was made which verifies that the new algorithm can optimize satellite selection and improve performance of navigation system under high dynamic condition.