宋伟伟, 何成鹏, 辜声峰. 不同纬度区域电离层增强PPP-RTK性能分析[J]. 武汉大学学报 ( 信息科学版), 2021, 46(12): 1832-1842. DOI: 10.13203/j.whugis20210243
引用本文: 宋伟伟, 何成鹏, 辜声峰. 不同纬度区域电离层增强PPP-RTK性能分析[J]. 武汉大学学报 ( 信息科学版), 2021, 46(12): 1832-1842. DOI: 10.13203/j.whugis20210243
SONG Weiwei, HE Chengpeng, GU Shengfeng. Performance Analysis of Ionospheric Enhanced PPP-RTK in Different Latitudes[J]. Geomatics and Information Science of Wuhan University, 2021, 46(12): 1832-1842. DOI: 10.13203/j.whugis20210243
Citation: SONG Weiwei, HE Chengpeng, GU Shengfeng. Performance Analysis of Ionospheric Enhanced PPP-RTK in Different Latitudes[J]. Geomatics and Information Science of Wuhan University, 2021, 46(12): 1832-1842. DOI: 10.13203/j.whugis20210243

不同纬度区域电离层增强PPP-RTK性能分析

Performance Analysis of Ionospheric Enhanced PPP-RTK in Different Latitudes

  • 摘要: 收敛速度慢一直是限制精密单点定位(precise point positioning, PPP)发展的重要因素。研究表明,通过高精度电离层延迟改正,进而实现精密单点定位实时动态(PPP-real time kinematic,PPP-RTK),可显著提升PPP的收敛速度。目前区域PPP-RTK中电离层主要采用单星多项式电离层模型(satellite-based ionospheric model with polynomial function,SIM_POLY)与单星电离层延迟反距离内插模型(satellite-based ionospheric model with inverse distance weight function,SIM_IDW)进行建模。为了检验上述两种模型在不同纬度的建模精度,对中国广东、湖北及河北3个省上空电离层延迟进行建模,并将其应用于单/双系统、浮点解及固定解中,分析其定位性能。实验结果表明,在低纬度区域,SIM_IDW模型表现略优于SIM_POLY模型,中高纬度区域则并无显著差异。浮点解PPP中,将SIM_IDW模型及SIM_POLY模型改正下的结果与无电离层组合PPP(ionosphere-free combination PPP, IFPPP)及欧洲定轨中心(Centre for Orbit Determination in Europe,CODE)的全球电离层格网(global ionospheric map,GIM)改正下的非差非组合结果进行比较,发现区域电离层模型改正下的PPP定位效果更好;与湖北省及广东省定位结果相比,河北省数据收敛速度最快,单GPS解算模式下采用SIM_IDW及SIM_POLY模型改正下的定位精度相较于IFPPP分别提升了43.7%和43.0%。固定解PPP中,河北省GPS+北斗解算模式下SIM_IDW、SIM_POLY模型改正下的PPP-RTK首个历元模糊度固定成功率分别可达86.09%和89.13%,且水平方向定位精度首个历元收敛至5 cm,高程方向定位精度1.5 min内收敛至10 cm;定位精度方面,在引入北斗系统之后,双系统PPP-RTK相较于单GPS有明显提升,河北省GPS+北斗解算模式下SIM_IDW、SIM_POLY模型改正下的PPP-RTK水平及三维定位精度分别为1.3 cm和3.5 cm。通过SIM_IDW及SIM_POLY模型建立区域电离层模型进而实现PPP-RTK,可以显著缩短PPP收敛时间,提高定位精度。

     

    Abstract:
      Objectives  Slow convergence has always been an important factor of limiting the development of precise point positioning (PPP). Studies have shown that the convergence speed of PPP can be significantly improved with high-precision ionospheric delay correction, and then to achieve PPP-real time kinematic (PPP-RTK). At present, the ionosphere in the regional PPP-RTK mainly adopts the satellite-based ionospheric model with polynomial function (SIM_POLY) and the satellite-based ionospheric model with inverse distance weight function (SIM_IDW) for construction.
      Methods  In order to verify the modeling accuracy of the above two models at different latitudes, this paper first used the observation data of Guangdong, Hubei and Hebei provinces to establish ionospheric delay models, and then applied the above models to float and fixed solutions PPP under single GPS and GPS+BDS systems. Finally the results were compared with IFPPP (ionosphere-free PPP) and CODE GIM (Centre for Orbit Determination in Europe Global Ionospheric Map, CODG) correction.
      Results  Experimental results showed that in the low-latitude provinces, SIM_IDW model slightly outperformed SIM_POLY model, but there was no significant difference in the middle and high latitude provinces. Compared with IFPPP and CODG correction, PPP under SIM_IDW and SIM_POLY correction has a better performance. Besides, Hebei province achieved the fastest convergence speed compared with Guangdong and Hubei provinces, and compared with IFPPP, the positioning accuracy in single GPS solution under SIM_IDW and SIM_POLY model correction is improved by 43.7% and 43.0%, respectively. In the fixed PPP, the success rate of first epoch to fix the ambiguity of PPP-RTK under the correction of SIM_IDW and SIM_POLY models in GPS+BDS solution could reach 86.09% and 89.13% in Hebei province. Besides, positioning accuracy could converge to 5 cm in the first epoch in horizontal direction, and converge to 10 m within 1.5 minutes in vertical direction. The positioning accuracy after convergence of GPS+BDS PPP-RTK had a significant improvement compared with single GPS, which was 1.3 cm in horizontal direction and 3.5 cm in three-dimensional direction under the correction of SIM_IDW and SIM_POLY models.
      Conclusions  Establishing a regional ionospheric model through SIM_IDW and SIM_POLY models to realize PPP-RTK can significantly shorten the PPP convergence time and improve positioning accuracy.

     

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