测绘学报 ›› 2021, Vol. 50 ›› Issue (12): 1738-1750.doi: 10.11947/j.AGCS.2021.20200580

• 导航卫星系统 • 上一篇    下一篇

SSR延迟下的轨道钟差外推误差及其对多GNSS实时精密单点定位的影响评估

舒宝1,2,3, 王利1,2,3, 张勤1,2,3, 黄观文1,2   

  1. 1. 长安大学地质工程与测绘学院, 陕西 西安 710054;
    2. 地理信息工程国家重点实验室, 陕西 西安 710054;
    3. 西部矿产资源与地质工程教育部重点实验室, 陕西 西安 710054
  • 收稿日期:2020-12-07 修回日期:2021-08-19 发布日期:2022-01-08
  • 通讯作者: 王利 E-mail:wangli@chd.edu.cn
  • 作者简介:舒宝(1990—),男,讲师,研究方向为GNSS高精度卫星导航定位算法及应用。
  • 基金资助:
    国家自然科学基金(42004024;41877289);中国博士后科学基金面上项目(2020M673321);陕西省自然科学基础研究计划(2021JQ-230);中央高校基本科研业务费专项(300102261305)

Evaluation of multi-GNSS orbit and clock extrapolating error and their influence on real-time PPP during outages of SSR correction

SHU Bao1,2,3, WANG Li1,2,3, ZHANG Qin1,2,3, HUANG Guanwen1,2   

  1. 1. College of Geological Engineering and Geomatics, Chang'an University, Xi'an 710054, China;
    2. State Key Laboratory of Geographic Information Engineering, Xi'an 710054, China;
    3. Key Laboratory of Western China's Mineral Resources and Geological Engineering, Ministry of Education, Xi'an 710054, China
  • Received:2020-12-07 Revised:2021-08-19 Published:2022-01-08
  • Supported by:
    The National Natural Science Foundation of China (Nos. 42004024;41877289);The China Postdoctoral Science Foundation (No. 2020M673321);The Natural Science Basic Research Program of Shanxi (No. 2021JQ-230);The Fundamental Research Funds for the Central Universities,CHD (No. 300102261305)

摘要: 对于实时精密单点定位用户,一般需通过无线网络接入基于状态空间表述(SSR)的差分改正数信息。在实际应用中,由通信链路不稳定导致精密轨道钟差改正数发生延迟的现象十分普遍。对于多模GNSS组合实时定位而言,不同系统的卫星轨道类型和卫星钟性能不同,在发生SSR延迟时的轨道钟差精度保持能力各具特点,此时采用常规模型难以有效维持实时精密定位的精度及可用性。本文基于CNES提供的GPS、GLONASS、BDS-2、BDS-3和Galileo实时精密产品,详细分析了不同SSR延迟下4个系统卫星轨道及钟差的外推误差,并评估了外推误差对多模GNSS实时精密定位的影响。研究结果表明,随着SSR延迟时间的增长,轨道钟差外推精度随之降低,然而,同样延迟下,不同GNSS卫星的轨道钟差外推误差存在显著差异,在SSR延迟为10 min时,GLONASS卫星轨道及钟差外推引起的空间信号测距误差分别可达20.9和7.3 cm(钟差已通过光速换算为距离),而BDS和Galileo卫星轨道及钟差外推引起的空间信号测距误差均可保持在2.2 cm以内,SSR延迟下BDS和Galileo实时定位性能保持能力明显优于GLONASS和GPS。相比传统实时定位模型,采用6 h更新的超快速精密轨道并顾及多模GNSS不同卫星钟差的外推误差特性时,SSR延迟下的四系统组合实时定位性能显著提升,在SSR延迟为10 min时,其水平和高程方向的定位精度仍可保持在1.7和2.1 cm。本文的研究对于提升实时定位的稳健性及优化SSR产品的播发频率具有重要参考价值。

关键词: 多模GNSS, SSR延迟, 实时定位, 轨道外推误差, 钟差外推误差

Abstract: For real-time precise point positioning (PPP) users, the State Space Representation (SSR) messages from the server are usually transmitted by wireless data link. Due to unstable communication links in practical applications, it is common that the real-time orbit and clock streams are delivered to the users at certain time delays. For multi-GNSS combined positioning, the satellite orbit and clock types for GPS, GLONASS, BDS, and Galileo are different, the ability to maintain orbit and clock accuracy will be of different characteristics when SSR delay occurs. In this condition, it is difficult to maintain the real-time precision positioning accuracy and availability with conventional models. In this study, the orbit and clock extrapolating errors are evaluated based on GPS, GLONASS, BDS-2, BDS-3, and Galileo SSR products from CNES; and the performance of real-time positioning during outages of SSR correction are also analyzed for these four systems. The experiment results show that the accuracy of the orbital clock extrapolation decreases with the increase of the SSR delay time. However, significant differences in the orbital clock extrapolation errors are observed for different GNSS satellites under the same SSR delay. For 10 minutes SSR delay, the GLONASS signal-in-space range errors (SISREs) caused by orbit and clock offset extrapolation can reach 20.9 and 7.3 cm, respectively, while the BDS and Galileo SISREs caused by orbit and clock offset extrapolation can be kept within 2.2 cm, the clock offset has been converted to distance by the light speed. The performance of BDS and Galileo real-time positioning under SSR delays are significantly better than that of GLONASS and GPS. Compared with the traditional model, the four-system combined real-time positioning performance under SSR delay situation is significantly improved when ultra-rapid precise orbits are used and the clock extrapolation error characteristics for different satellites are considered. Using this new model, the positioning accuracy in the horizontal and vertical directions can maintain at 1.7 and 2.1 cm under 10 minutes SSR delay. This research has important reference value for improving the robustness of real-time positioning and optimizing the SSR update rate.

Key words: multi-GNSS, SSR time delay, real-time positioning, orbit extrapolating error, clock extrapolating error

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