北斗广域实时精密定位服务系统研究与评估分析

采用IGS、MGEX、北斗地基增强网的实时观测数据,研制北斗广域精密定位服务系统,实时生成北斗高精度轨道、钟差、电离层产品,提供厘米级北斗双频PPP、分米级单频PPP、米级单频伪距定位服务。对实时产品评估分析的结果表明:北斗卫星实时轨道与钟差产品URE统计精度约为2.0cm,实时电离层精度优于4.0TECU。采用全国分布的实时测站动态定位精度(95%置信度)评估分析表明:北斗双频PPP精度存在明显的区域特征,高纬度以及西部边缘地区的定位精度平面约0.2m,高程约0.3m;中部地区定位精度平面优于0.1m,高程优于0.2m,接近GPS实时PPP精度水平;北斗与GPS融合可以提高单北斗、单GPS的定位性能,尤其是显著加快了PPP收敛时间,收敛时间缩短到20min内。另外,除边缘地区外,北斗单频PPP实现平面0.5m,高程1.0m;北斗单频伪距单点定位实现平面2.0m,高程3.0m。

Research and Evaluation of BDS Real-time Wide-area Precise Positioning Service System

By adopting the real-time observations of IGS, multi-GNSS experiment (MGEX) and national BDS augmentation service system (NBASS), BDS real-time wide-area precise positioning service system is developed, which can generate high accuracy BDS real-time orbits, clocks and ionosphere products and provide centimeter-, decimeter-and meter-level positioning service with different positioning modes including BDS dual-and single-frequency precise point positioning (PPP) and single point positioning (SPP). The evaluation results of real-time products show that the user range error (URE) of BDS real-time orbits and clocks is about 2.0 cm and the accuracy of real-time ionosphere products is better than 4.0 TECU. The performance of real-time kinematic positioning at the 95% confidence level is evaluated by real-time stations across China. It reveals that the BDS dual-frequency PPP shows significant regional characteristic, the accuracy in high-latitude and western fringe region is about 0.2 m and 0.3 m in the horizontal and vertical component, respectively, while the horizontal accuracy is better than 0.1 m and the vertical accuracy is better than 0.2 m in the midlands, which is close to the accuracy of GPS real-time PPP. By the combination of BDS and GPS, the BDS/GPS PPP can improve the positioning performance of GPS or BDS PPP, especially improves the PPP convergence time significantly and the convergence time is within 20 min. In addition, except the fringe region, BDS single-frequency PPP can achieve 0.5 m in horizontal component and 1.0 m in vertical component, BDS SPP can achieve 2.0 m and 3.0 m in horizontal and vertical components, respectively.