BDS/GNSS精密单点定位性能分析

首先采用国际上通用的德国地学中心（GFZ）与武汉大学（WHU）精密产品，对GNSS精密卫星轨道和精密钟差产品精度进行初步评估；然后基于WHU精密轨道和钟差产品对18个分布于东半球的MGEX地面站进行多系统定位测试，同时也对BDS的B1I/B3I与B1C/B2a两组新、旧频点的精密单点定位性能进行对比分析。结果表明：1）四大导航系统（GPS、GLONASS、BDS、Galileo）的卫星轨道产品精度均在cm级，精密钟差内符合精度均优于0.1 ns，北斗三号（BDS-3）卫星钟精度相比北斗二号（BDS-2）有显著提升。2）亚太地区BDS的定位精度优于其他3个系统；在其他地区，GPS定位精度最优（与Galileo基本相当），优于BDS和GLONASS的定位结果。3）BDS PPP平均收敛时间静态模式约为50.33 min、动态模式约为77.83 min，收敛速度略低于GPS、Galileo，优于GLONASS。4）B1C/B2a与B1I/B3I双频消电离层组合PPP定位性能基本相当。

Assessment of BDS/GNSS Precise Point Positioning Performance

Using GFZ and WHU precise products, we compare and analyze the accuracy of GNSS precise products. We then select 18 MGEX stations distributed in the eastern hemisphere for BDS/GPS/GLONASS/Galileo PPP experiments based on WHU precise products and investigate the PPP performances of the BDS B1C/B2a and B1I/B3I ionosphere-free combinations. The results show that the accuracy of GNSS orbit products is at the cm level, and the STD of GNSS precise clock is better than 0.1 ns. We find that BDS-3 satellite clock accuracy is significantly improved compared to BDS-2. The PPP experiments show that the PPP performance of BDS is the best in the Asia-Pacific region, and in non-Asia-Pacific region, GPS positioning accuracy is better. The convergence times of BDS static and kinematic PPP are 50 mins and 78 mins, which are lightly slower than that of GPS and Galileo, and better than that of GLONASS. The comparison shows that the PPP performance of the B1C/B2a and B1I/B3I dual-frequency combinations is basically comparable.