SINS/GPS组合导航系统选星算法

Algorithm of satellite selection used in SINS/GPS integrated navigation system

选星算法是SINS/GPS组合导航定位系统中一个重要的步骤。在最佳选星算法的基础上,提出了一种适用于基于伪距、伪距率的SINS/GPS紧耦合组合系统的选星算法。该算法通过ENU(东北天)坐标系中几何矩阵及几何精度因子的定义,利用星历给出的卫星在ENU坐标系中的高度角和方位角解算出最佳四颗导航定位卫星,即基于G矩阵的选星算法。通过与两种常规选星算法的对比,验证了本算法具有较强的工程实用性。此外又推导了基于G矩阵的伪距、伪距率的SINS/GPS组合系统量测方程。该算法避免了求解卫星的位置,从而有效减少了计算量。

Algorithm of satellite selection is a very important approach for the tightly coupled navigation system of SINS/GPS. Based on the classical optimal algorithm of GPS constellation, an improved algorithm was presented. It was more applicable to the tightly coupled navigation system of SINS/GPS which was based upon pseudo range and pseudo range rate. Through the definition of geometric matrix and geometric dilution of precision in the ENU coordinates, four optimal satellites were chosen according to the elevation and azimuth given in the ENU coordinates. It verifies that the new algorithm is concision, adaptable, and is liable to be implemented in engineering by comparing two traditional selection algorithms. Furthermore, the observation matrix equations of SINS/GPS based on G matrix was demonstrated, the algorithm avoided computing satellite’s position and reduced computing time effectively.