摘要
区域北斗星基增强系统提供等效钟差改正数统一修正星历和钟差误差。随着系统的建设发展,新一代北斗星基增强系统将区分星历和钟差误差改正信息,以提高差分改正精度。由于北斗卫星混合星座设计及区域监测网的局限,星历和钟差误差的高精度分离计算面临着新的挑战。对北斗星基增强系统的星历和钟差改正算法进行了研究,分别采用动力学和运动学模式计算了卫星星历和钟差改正数,并基于北斗实测数据,对两种处理模式的差分改正精度进行了对比研究。试验结果表明,采用动力学和运动学差分方法,得到的双频伪距实时定位精度分别为1.76m和1.78m,定位精度与WAAS及EGNOS相当。利用运动学和动力学差分改正数后均可得到分米级的精密单点定位(precise point position,PPP)结果,其中采用动力学广域差分改正数,收敛后定位精度可达到15cm;采用运动学广域差分改正数,收敛后定位精度可达45cm。
The regional BeiDou wide area differential augmentation system provides onedimensional equivalent satellite clock correction to uniform satellite clock and ephemeris error. With the development of system construction, the global BeiDou wide area differential augmentation system will distinguish between satellite orbit correction and satellite clock correction to improve the accuracy of differential correction. Due to the limitations of the Beidou hybrid constellation design and the regional monitoring network, it poses a challenge for the high precision separation of orbital and satellite clock error. In this paper, we study the satellite orbit and clock offset estimation algorithms of the BeiDou wide area differential augmentation system, the processing strategies of dynamic and kinematic wide area differential algorithms are compared and analyzed, and the positioning accuracy of two methods is compared based on the BeiDou measured data. The results show that: using dynamic,kinematic wide area differential model, the dual frequency real-time positioning accuracy are 1.76 m and 1.78 m, which are comparable with the performance of WAAS and EGNOS. The dynamic and kinematic wide area differential modes can all get decimeter-level precise point positioning(PPP) results. With dynamic corrections, the precision of PPP experiments may reach to about 15 cm after convergence.
引文
[1] Satellite Based Augmentation System Interoperability Working Group. SBAS L5 DFMC Interface Control Document. Issue 1, Rev 3. Dakar:SBAS IWG, 2016:35
[2] Tsai Y. Dissertation. California:Stanford University, 1999
[3] 陈刘成,胡小工,封欣,等.中国科学院上海天文台年刊, 2010, 31:45
[4] Cao Y, Hu X, Zhou J, et al. Lecture Notes in Electrical Engineering, 2014, 305(3):277
[5] 吴显兵.博士论文.西安:长安大学, 2016:81
[6] 宋伟伟.博士论文.武汉:武汉大学, 2011:39
[7] Lou Y, Liu Y, Shi C, et al. Scienti?c Reports, 2014, 4(8):4692
[8] Li X, Ge M, Dai X, et al. Journal of Geodesy, 2015, 89(6):607
[9] Tang C, Hu X, Zhou S. Advances in Space Research, 2016, 58(7):1390
[10] 中国卫星导航系统管理办公室.北斗卫星导航系统空间信号接口控制文件公开服务信号B1I. 1.0版.(2012).http://www.beidou.gov.cn/xt/gfxz/
[11] Wu X, Zhou J, Wang G, et al. SCINECE CHINA:Physics, Mechanics&Astronomy, 2012, 55(12):1297
[12] Cao Y, Hu X, Wu B, et al. SCINECE CHINA:Physics, Mechanics&Astronomy, 2012, 55(12):1130
[13] Zhou S, Cao Y, Zhou J, et al. SCINECE CHINA:Physics, Mechanics&Astronomy, 2012, 55(12), 2290