星载单频GPS实时精密定轨模型研究

采用星载单频GPS伪距和相位观测数据,构建单频伪距相位无电离层组合(GRAPHIC)消除电离层延迟误差的影响,同时建立伪模糊度参数随机模型,吸收广播星历中的轨道和钟差误差。对国内外8颗低轨卫星星载GPS实测数据进行单频实时定轨模拟解算,结果表明,使用GRAPHIC组合作为主要观测值,实时定轨位置精度达到0.44~0.55m,速度精度达到0.37~0.63mm/s,相比于传统的基于双频伪距观测值的实时定轨方式,定轨精度提升40%左右。根据本文星载单频GPS定轨模型和算法,仅使用低成本的单频GPS观测即可以实现低轨卫星高精度实时定轨。

Precise Real-Time Orbit Determination Model Using Space-Borne Single-Frequency GPS Observations

To eliminate the influence of the ionosphere we construct the group and phase ionosphere correction (GRAPHIC) with single-frequency GPS pseudo-range and phase observations. At the same time, we add pseudo-ambiguity parameter to the orbit determination filter to absorb the broadcast ephemeris errors. We assess the absorption effect and accuracy of real-time orbit determination for space-borne single-frequency GPS with real GPS measurements of 8 different low earth orbit satellites. The results show that the accuracy of real-time orbit determination improves greatly with GRAPHIC measurements. The position accuracy is 0.44-055 m and the velocity is 0.37-0.63 mm/s. The accuracy improvement is about 40% compared to the traditional dual-frequency pseudo-range real-time orbit determination method. We believe that with the real-time orbit determination algorithm mentioned in this paper, high precise orbit determination results can be achieved with low-cost single-frequency GPS receiver.