随着中国BeiDou系统与欧盟Galileo系统的出现以及俄罗斯GLONASS系统的恢复完善,过去单一的GPS导航卫星系统时代已经逐步过渡为多系统并存且相互兼容的全球性卫星导航系统(multi-constellation global navigation satellite systems,multi-GNSS)时代,多系统GNSS融合精密定位将成为未来GNSS精密定位技术的发展趋势。本文采用GPS、GLONASS、BeiDou、Galileo 4大卫星导航定位系统融合的精密单点定位(precise point positioning,PPP)实测数据,初步研究并分析了4系统融合PPP的定位性能。试验结果表明:在单系统观测几何构型不理想的区域,多系统融合能显著提高PPP的定位精度和收敛速度。4大系统融合的PPP收敛速度相对于单GNSS可提高30%~50%,定位精度可提高10%~30%,特别是对高程方向的贡献更为明显。此外,在卫星截止高度角大于30°的观测环境下,单系统由于可见卫星数不足导致无法连续定位,而多系统融合仍然可以获得PPP定位结果,尤其是水平方向具有较高的定位精度。这对于山区、城市以及遮挡严重的区域具有非常重要的应用价值。
With the appearance of China's BeiDou system and EU's Galileo system and the restoration and improvement of Russia's GLONASS navigation system, the single GPS navigation satellite system has been gradually developed into multi-GNSS (multi-constellation global navigation satellite systems). Multi-GNSS with precise positioning will become the development trend of GNSS precise positioning in the future. Using the observation data collected by PPP (precise point positioning), which integrates the four major satellite navigation systems of GPS、 GLONASS、 BeiDou and Galileo, this paper conducts a preliminary study and analyzes the positioning performance of multi-system PPP. According to the experiment, in areas where single system observation geometrical configuration is unsatisfactory, multi-system integration can greatly improve the positioning accuracy and convergence rate of PPP. The convergence rate of multi-constellation PPP is 30% to 50% higher than that of single GPS, and the positioning accuracy can also be improved 10% to 30%, especially in terms of elevation direction. Besides, under observation circumstance where the end elevation angle of satellite is larger than 30 degrees, single GPS fails to carry out continuous positioning due to lack of visible satellites, while multi-constellation PPP can still get positioning results, with relatively high accuracy in horizontal direction especially.
[1] GAO Yang, SHEN Xiaobing.Improving Ambiguity Convergence in Carrier Phase-based Precise Point Positioning[C]//Proceedings of the 14th International Technical Meeting of the Satellite Division of the Institute of Navigation (ION GPS2001). Salt Lake City:Salt Palace Convention Center, 2001:1532-1539.
[2] CHEN Wu, HU Congwei, LI Zhihua, et al. Kinematic GPS Precise Point Positioning for Sea Level Monitoring with GPS Buoy[J]. Journal of Global Positioning Systems, 2004, 3(1-2): 302-307.
[3] ZHANG Xiaohong, ANDERSEN O B. Surface Ice Flow Velocity and Tide Retrieval of the Amery Ice Shelf Using Precise Point Positioning[J]. Journal of Geodesy, 2006, 80(4): 171-176.
[4] BISNATH S, GAO Yang. Current State of Precise Point Positioning and Future Prospects and Limitations[M]//SIDERIS M G.Observing Our Changing Earth. Berlin: Springer, 2007, 133: 615-623.
[5] ZHANG Xiaohong, LIU Jingnan, FORSBERG R. Application of Precise Point Positioning in Airborne Survey[J]. Geomatics and Information Science of Wuhan University, 2006, 31(1): 19-22, 46. (张小红, 刘经南, FORSBERG R. 基于精密单点定位技术的航空测量应用实践[J]. 武汉大学学报: 信息科学版, 2006, 31(1): 19-22, 46.)
[6] YUAN Xiuxiao, FU Jianhong, LOU Yidong. GPS-supported Aerotriangulation Based on GPS Precise Point Positioning[J]. Acta Geodaetica et Cartographica Sinica, 2007, 36(3): 251-255. (袁修孝, 付建红, 楼益栋. 基于精密单点定位技术的GPS辅助空中三角测量[J]. 测绘学报, 2007, 36(3): 251-255.)
[7] ZHANG Baocheng, OU Jikun, YUAN Yunbin, et al. Precise Point Positioning Algorithm Based on Original Dual-frequency GPS Code and Carrier-phase Observations and Its Application[J]. Acta Geodaetica et Cartographica Sinica, 2010, 39(5): 478-483. (张宝成, 欧吉坤, 袁运斌, 等. 基于GPS双频原始观测值的精密单点定位算法及应用[J]. 测绘学报, 2010, 39(5): 478-483.)
[8] ZHANG Xiaohong, HE Xiyang, LI Xingxing. Analysis of Undifferenced Kinematic POD for LEOs Using Trip[J]. Geomatics and Information Science of Wuhan University, 2010, 35(11): 1327-1330. (张小红, 何锡扬, 李星星. Trip软件非差几何法精密定轨精度分析[J]. 武汉大学学报: 信息科学版, 2010, 35(11): 1327-1330.)
[9] ZHANG Baocheng, OU Jikun, YUAN Yunbin, et al. Calibration of Slant Total Electron Content and Satellite-receiver's Differential Code Biases with Uncombined Precise Point Positioning Technique[J]. Acta Geodaetica et Cartographica Sinica, 2011, 40(4): 447-453. (张宝成, 欧吉坤, 袁运斌, 等. 利用非组合精密单点定位技术确定斜向电离层总电子含量和站星差分码偏差[J]. 测绘学报, 2011, 40(4): 447-453.)
[10] SHI Chuang, ZHAO Qile, LI Min, et al. Precise Orbit Determination of BeiDou Satellites with Precise Positioning[J]. Science China Earth Sciences, 2012, 55(7): 1079-1086. (施闯, 赵齐乐, 李敏, 等. 北斗卫星导航系统的精密定轨与定位研究[J]. 中国科学: 地球科学, 2012, 42(6): 854-861.)
[11] MONTENBRUCK O, STEIGENBERGER P, KHACHIKYAN R,et al. IGS-MGEX: Preparing the Ground for Multi-constellation GNSS Science[J]. Inside GNSS, 2014, 9:42-49.
[12] PÍRIZ R, CALLE D, MOZO P,et al.Orbits and Clocks for GLONASS Precise-point-positioning[C]//Proceedings of the 22nd International Technical Meeting of the Satellite Division of the Institute of Navigation (ION GNSS 2009). Savannah:Savannah International Convention Center, 2009: 2415-2424.
[13] MELGARD T, VIGEN E, DE JONG K, et al.G2: the First Real-time GPS and GLONASS Precise Orbit and Clock Service[C]//Proceedings of the 22nd International Technical Meeting of the Satellite Division of the Institute of Navigation (ION GNSS 2009). Savannah: Savannah International Convention Center, 2009: 1885-1891.
[14] MELGARD T, VIGENE, ØRPEN O, et al. Pulling in All Signals PPP with GPS and GLONASS: The New G2[J]. GPS World, 2010, 21(3): 28.
[15] DACH R, LUTZS,MEINDLM, et al. Combining the Observations from Different GNSS[C]//EUREF 2010 Symposium. Gävle:Bundesamtfür Kartographie und Geodäsie,2010.
[16] ZHANG Xiaohong, GUO Fei, LI Xingxing, et al. Study onPrecise Point Positioning Based on Combined GPS and GLONASS[J]. Geomatics and Information Science of Wuhan University,2010, 35(1): 9-12. (张小红, 郭斐, 李星星, 等. GPS/GLONASS组合精密单点定位研究[J]. 武汉大学学报: 信息科学版,2010, 35(1): 9-12)
[17] LI Pan, ZHANG Xiaohong. Integrating GPS withGLONASS to Accelerate Convergence and Initialization Times of Precise Point Positioning[J].GPS Solutions, 2014, 18(3): 461-471.
[18] CAI Changsheng,GAO Yang. Modeling and Assessment of Combined GPS-GLONASS Precise Point Positioning[J]. GPS Solutions, 2013, 17(2): 223-236.
[19] CHEN Junping, XIAO Pei, ZHANG Yize, et al. GPS-GLONASS System Bias Estimation and Application in GPS-GLONASS Combined Positioning[C]//SUN Jiadong, JIAO Wenhai, WU Haitao,et al. Lecture Notes in Electrical Engineering: China Satellite Navigation Conference (CSNC) 2013 Proceedings, 2013, 244: 323-333.
[20] ZHANG Xiaohong, ZUO Xiang, LI Pan, et al. ConvergenceTime and Positioning Accuracy Comparison between BDS and GPS Precise Point Positioning[J]. Acta Geodaeticaet Cartographica Sinica, 2015, 44(3): 250-256. (张小红, 左翔, 李盼, 等. BDS/GPS精密单点定位收敛时间与定位精度的比较[J]. 测绘学报, 2015, 44(3): 250-256.)
[21] CHEN Junping, ZHANG Yize, WANG Jungang, et al. A Simplified and Unified Model of Multi-GNSS Precise Point Positioning[J]. Advances in Space Research, 2015, 55(1): 125-134.
