北斗三号组网卫星数据质量分析及单系统定轨精度初步评估

选取2018-01-23起10 d内16个iGMAS测站观测数据，对北斗三号卫星的观测数据质量及BDS单系统精密定轨精度进行评估。初步结果表明，老信号B1I、B3I北斗三号卫星的信噪比略强于二号卫星，噪声与多路径基本相当，均在0.1 m量级，新卫星不存在星内多路径偏差。新信号B1C/L1/E1频点GPS信噪比最强，Galileo和BDS卫星相当，B2a/L5/E5a和B2b/E5b各系统基本相当；噪声及多路径方面，B1C/L1/E1频点GPS优于BDS、Galileo卫星0.1 m量级，B2a/L5/E5a和B2b/E5b各系统基本相当，均在0.1 m量级，新信号中北斗三号卫星星内多路径偏差基本消失。单系统精密定轨试验中，分别进行有/无GEO卫星策略、太阳光压模型ECOM 五/九参数策略的比较，并使用卫星激光测距数据进行独立检核。初步结果表明，有GEO卫星、ECOM五参数光压模型的定轨精度最好，C19号卫星7个重叠弧段的平均定轨精度在沿迹向、法向、径向的精度分别为32 cm、16 cm、8 cm，与试验卫星的定轨精度基本相当。

Initial Evaluation of Beidou-3 Satellite Data Quality and Single System Precise Orbit Determination

By selecting 16 iGMAS station observation data for 10 days from January 23, 2018, the observation data quality of third-generation Beidou satellite (BDS-3) and the orbit accuracy of BDS-3 satellites satellite are evaluated using BDS-only precise orbit determination (POD). In the data quality analysis, two stations with different receiver types are selected to evaluate the signal-to-noise ratio (SNR), pseudorange noise and multipath error for Beidou new and old signals, comparing them with GPS Block ⅡF and Galileo FOC satellite. The pseudorange noises of all stations are calculated and analyzed. The results show that the signal-to-noise ratio of B1I and B3I for BDS-3 satellite is slightly stronger than those of BDS-2 satellites. The noise multipaths are considerable between BDS-2 and BDS-3 satellites, both of which are at the magnitude of 0.1m. BDS-3 satellites do not have satellite-induced code pseudorange variations. As to the new signals, the B1C/L1/E1 SNR is strongest for GPS satellites, and the Galileo is equivalent to the BDS satellite. The SNR among three GNSS systems in B2a/L5/E5a and B2b/E5b frequencies are basically equivalent. In terms of noise and multipath, B1C/L1/E1 GPS is superior to BDS and Galileo, with the magnitude of 0.1m. B2a/L5/E5a and B2b/E5b are basically the same, both at the magnitude of 0.1m. In BDS-only POD tests, strategies with/without GEO satellite and ECOMfive or nineparameters were respectively compared, and the satellite laser ranging data are used for independent check. The results show that the orbits with GEO satellite and selecting ECOM fiveparameters can receive the best accuracy. The average orbit determination precisions of C19 satellite with 7 overlapping arcs are 32, 16 and 8 cm in along, cross and radial directions, respectively.