北斗系统在南极中山站地区的基本定位性能评估

Preliminary Assessment of Positioning Performance of BeiDou Navigation Satellite System at Zhongshan Station,Antarctica

对北斗区域卫星导航系统(BDS)正式运行后在南极中山站地区的基本导航定位性能进行了评估,包括卫星可用性、位置精度因子(PDOP)、伪距观测值质量、电离层模型精度及单频伪距导航定位性能等方面。对南极中山站地区实测数据分析的结果表明,首先,北斗卫星导航系统的可用性与伪距观测值质量在总体上与GPS处于同一水平,并已初步具备了全天导航定位的能力,但存在卫星分布不够均匀、GEO卫星高度角较低、电离层模型精度较差等问题。其次,北斗单频伪距单点定位北、东方向的精度分别优于22m和9m,高程方向优于25m;超短基线的单频伪距差分定位在北、东、高程三个方向的精度分别为3.6m、2.3m和3.3m;总体而言与GPS相比有一定差距。最后,北斗/GPS组合定位相对于单一的GPS定位不仅增加了系统的可靠性,还对定位的精度有明显改善,对于单频伪距单点定位、伪距差分定位的三维点位精度可分别提高10%、22%。

This paper assesses the navigation and positioning performance of BeiDou Navigation Satellite System at Zhongshan station,Antarctic,after it is officially announced in operation.The availability of satellites,position dilution of precision,pseudorange data quality,precision of ionosphere model and positioning accuracy are analyzed by real data.The results show that：1）BeiDou is currently capable of providing basic navigation and positioning services through all day at Zhongshan Antarctic station.The overall availability and quality of pseudorange measurements of BeiDou is as good as that of GPS.However,there are some problems,such as uneven distributed satellites over the sky,low elevation of GEO satellites,and the low accuracy of ionosphere model,which would reduce the positioning performance.2）The precision of BeiDou-only positioning is much worse than that of GPSonly solutions;for single-frequency point positioning,we can only expect accuracies higher than22 m,9mand 25 min the north,east and up component,respectively;for single-frequency pseudorange differential positioning,the accuracies are 3.6 m,2.3 mand 3.3 min the north,east and up component,respectively.3）The combined system of GPS and BeiDou provides increased reliability and improves the 3Dprecision of GPS by approximately 10 percent,22percent for single-frequency point positioning and single-frequency pseudorange differential positioning,respectively.