北斗/GPS组合系统精密单点定位算法研究

Combined Beidou/GPS precise point positioning for weak signals

在利用多系统组合定位导航时,由于各个系统之间存在的系统间时钟差而导致的待估参数增多,计算复杂高。针对以上问题,本文提出一种改进的组合北斗/GPS精密单点定位算法,该算法利用传统的精密单点定位的算法求得系统间时钟差、对流层延迟和接收机的硬件延迟,将它们作为改进算法的先验信息,从而减少GNSS定位解算时的待估参数个数,大大减少计算量。仿真结果表明:在可见卫星数目较少的情况下,改进算法能够有效的提高定位精度及效率。

When the multi -system combination positioning navigation is used, the estimation parameters are increased due to the difterence of inter - system clock between each system, and the calculation is complex and high. A combined Beidou/GPS precise point positioning algorithm is proposed in this paper to solve the above problems. In the modified algorithm, the system time difference between BDS and GPS, the zenith tropospheric delay （ZTD） and the device delay were estimated using the traditional algorithm, which were used as the priori information to reduce the number of unknown parameters in pseudo range observation equation, which can reduce the complexity and computation. The simulation results indicate that the modified algorithm can effectively improve the positioning accuracy and efficiency when the visible satellites is insufficient.