Real-time wide-area precise positioning and precise timing service system

doi:10.11947/j.AGCS.2022.20220153

Abstract

Abstract: Wide-area real-time accurate positioning and timing service has become a hotspot in the field of GNSS. At present, domestic and foreign scholars have carried out a lot of valuable research on the model and algorithm. The method of data processing and service system construction for real-time wide-area precise positioning (WPP) and wide-area precise timing (WPT) is investigated in this paper. Various clock datums, including the quasi-stable datum of satellite clocks, the quasi-stable datum of station atomic clocks, and the datum of standard time, are proposed for the constraint on clock estimation solution by introducing stations that are linked to external atomic frequency standard or the source of standard time (UTC/BDT) in the solution. Also, the impact of clock datum on PPP, precise point timing (PPT) is analyzed. In this paper, the real-time products of the satellite orbit, clock errors, phase biases and ionospheric delays, as well as the real-time tracking station data, are utilized to verify the products reliability of the system and the performance of terminal positioning and timing service. The results of the real-time products indicate that the average RMS of radial orbit errors is 1.8 cm and 6.7 cm, and the average STD of clock errors is about 0.05 ns and better than 0.1 ns for GPS and BDS-3, respectively; the accuracy of ionospheric delays is 0.74 TECU and 1.03 TECU for GPS and BDS-2, respectively. Based on the above products, PPP/PPP-RTK and PPT/PPT-RTK services that meet real-time positioning of centimeter-level and one-way timing better than 0.5 ns are realized. It takes about 12 min to reach the positioning accuracy under 5 cm for the horizontal component in the GPS+BDS-2 PPP-RTK solution.

Key words: wide-area real-time, PPP, PPT, PPP-RTK, PPT-RTK

CLC Number:

P227

SHI Chuang, GU Shengfeng, LOU Yidong, ZHENG Fu, SONG Wei, ZHANG Dong, MAO Feiyu. Real-time wide-area precise positioning and precise timing service system[J]. Acta Geodaetica et Cartographica Sinica, 2022, 51(7): 1206-1214.

References

[1] YANG Yuanxi, LI Jinlong, XU Junyi, et al. Contribution of the Compass satellite navigation system to global PNT users[J]. Chinese Science Bulletin, 2011, 56(26):2813-2819. DOI:10.1007/s11434-011-4627-4.
[2] 中国卫星导航系统管理办公室.北斗卫星导航系统公开服务性能规范(2.0版)[EB/OL].(2018-12). http://www.beidou.gov.cn/xt/gfxz/201812/P020181227529210661088. pdf. China Satellite Navigation Office. BeiDou navigation satellite system open service performance standard (Version 2.0).(2018-12). http://www.beidou.gov.cn/xt/gfxz/201812/P020181227529449178798.pdf.
[3] YANG Yuanxi, LIU Li, LI Jinlong, et al. Featured services and performance of BDS-3[J]. Science Bulletin, 2021, 66(20):2135-2143. DOI:10.1016/j.scib.2021.06.013.
[4] YANG Yuanxi, MAO Yue, SUN Bijiao. Basic performance and future developments of BeiDou global navigation satellite system[J]. Satellite Navigation, 2020, 1(1):1. DOI:10.1186/s43020-019-0006-0.
[5] MUELLERSCHOEN R J, REICHERT A, KUANG Da, et al. Orbit determination with NASA's high accuracy real-time global differential GPS system[C]//Proceedings of the 14th International Technical Meeting of the Satellite Division of the Institute of Navigation. Salt Lake City:Salt Palace Convention Center, 2001:2294-2303.
[6] MONTENBRUCK O, HAUSCHILD A, ANDRES Y, et al.(Near-) real-time orbit determination for GNSS radio occultation processing[J]. GPS Solutions, 2013, 17(2):199-209. https://doi.org/10.1007/s10291-012-0271-y.
[7] CAISSY M, AGROTIS L, WEBER G, et al. The international GNSS real-time service[J]. GPS World, 2012, 23(6):52-58.
[8] HADAS T, BOSY J. IGS RTS precise orbits and clocks verification and quality degradation over time[J]. GPS Solutions, 2015, 19(1):93-105.
[9] KAZMIERSKI K, SOŚNICA K, HADAS T. Quality assessment of multi-GNSS orbits and clocks for real-time precise point positioning[J]. GPS Solutions, 2018, 22:11.
[10] GE Maorong, GENDT G, ROTHACHER M, et al. Resolution of GPS carrier-phase ambiguities in Precise Point Positioning (PPP) with daily observations[J]. Journal of Geodesy, 2008, 82(7):389-399. DOI:10.1007/s00190-007-0187-4.
[11] GU Shengfeng, SHI Chuang, LOU Yidong, et al. Ionospheric effects in uncalibrated phase delay estimation and ambiguity-fixed PPP based on raw observable model[J]. Journal of Geodesy, 2015, 89(5):447-457.
[12] GENG Jianghui, CHEN Xingyu, PAN Yuanxin, et al. A modified phase clock/bias model to improve PPP ambiguity resolution at Wuhan University[J]. Journal of Geodesy, 2019, 93(10):2053-2067.
[13] REN Xiaodong, CHEN Jun, LI Xingxing, et al. Performance evaluation of real-time global ionospheric maps provided by different IGS analysis centers[J]. GPS Solutions, 2019, 23(4):113.
[14] LIU Qi, HERNÁNDEZ-PAJARES M, YANG Heng, et al. The cooperative IGS RT-GIMs:a reliable estimation of the global ionospheric electron content distribution in real time[J]. Earth System Science Data, 2021, 13(9):4567-4582.
[15] WVBBENA G, SCHMITZ M. BAGGE A. PPP-RTK:Precise point positioning using state-space representation in RTK networks[C]//Proceedings of the 18th International Technical Meeting of the Satellite Division of the Institute of Navigation. Long Beach, CA:ION, 2005.
[16] HE Chengpeng, GU Shengfeng, LIU Cheng, et al. Simulation research on PPP-RTK performance based on BDS GEO satellite[J]. Measurement Science and Technology, 2022, 33(6):065025.
[17] ALLAN D W, WEISS M A. Accurate time and frequency transfer during common-view of a GPS satellite[C]//Proceedings of the 34th Annual Symposium on Frequency Control. Philadelphia, PA:IEEE, 1980:334-346.
[18] PETIT G, JIANG Z. GPS All in view time transfer for TAI computation[J]. Metrologia, 2007, 45(1):35.
[19] RAY J, SENIOR K. IGS/BIPM pilot project:GPS carrier phase for time/frequency transfer and timescale formation[J]. Metrologia, 2003, 40(3):S270-S288.
[20] RAY J, SENIOR K. Geodetic techniques for time and frequency comparisons using GPS phase and code measurements[J]. Metrologia, 2005, 42(4):215-232.
[21] PETIT G, JIANG Zhiheng. Precise point positioning for TAI computation[J]. International Journal of Navigation and Observation, 2008, 2008:562878.
[22] WANG Shengli, ZHAO Xingwang, GE Yulong, et al. Investigation of real-time carrier phase time transfer using current multi-constellations[J]. Measurement, 2020, 166:108237.
[23] DEFRAIGNE P, AERTS W, POTTIAUX E. Monitoring of UTC (k)'s using PPP and IGS real-time products[J]. GPS Solutions, 2015, 19(1):165-172.
[24] TU Rui, ZHANG Pengfei, ZHANG Rui, et al. Modeling and performance analysis of precise time transfer based on BDS triple-frequency un-combined observations[J]. Journal of Geodesy, 2019, 93(6):837-847.
[25] PETIT G. Sub-10^-16 accuracy GNSS frequency transfer with IPPP[J]. GPS Solutions, 2021, 25(1):22.
[26] ROSE J A R, WATSON R J, ALLAIN D J, et al. Ionospheric corrections for GPS time transfer[J]. Radio Science, 2014, 49(3-4):196-206.
[27] GE Yulong, ZHOU Feng, LIU Tianjun, et al. Enhancing real-time precise point positioning time and frequency transfer with receiver clock modeling[J]. GPS Solutions, 2019, 23:20.
[28] 于合理,郝金明,刘伟平,等.附加原子钟物理模型的PPP时间传递算法[J].测绘学报, 2016, 45(11):1285-1292. DOI:10.11947/j.AGCS.2016.20160217. YU Heli, HAO Jinming, LIU Weiping, et al. A time transfer algorithm of precise point positioning with additional atomic clock physical model[J]. Acta Geodaetica et Cartographica Sinica, 2016, 45(11):1285-1292. DOI:10.11947/j.AGCS.2016.20160217.
[29] 施闯,楼益栋,宋伟伟,等.广域实时精密定位原型系统及初步结果[J].武汉大学学报(信息科学版), 2009, 34(11):1271-1274. SHI Chuang, LOU Yidong, SONG Weiwei, et al. A wide area real-time differential GPS prototype system and the initial results[J]. Geomatics and Information Science of Wuhan University, 2009, 34(11):1271-1274.
[30] SHI Chuang, ZHAO Qile, HU Zhigang, et al. Precise relative positioning using real tracking data from COMPASS GEO and IGSO satellites[J]. GPS Solutions, 2013, 17(1):103-119.
[31] 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. DOI:10.1007/s11430-012-4446-8.
[32] 蔡毅,施闯,欧阳星宇.北斗地基增强系统[M].北京:国防工业出版社, 2020. CAI Yi, SHI Chuang, OUYANG Xingyu. BeiDou navigation satellite system ground-based augmentation system[M]. Beijing:National Defense Industry Press, 2020.
[33] SHI Chuang, ZHENG Fu, LOU Yidong, et al. National BDS augmentation service system (NBASS) of China:progress and assessment[J]. Remote Sensing, 2017, 9(8):837. DOI:10.3390/rs9080837.
[34] 施闯,张东,宋伟,等.北斗广域高精度时间服务原型系统[J].测绘学报, 2020, 49(3):269-277. DOI:10.11947/j.AGCS.2020.20180534. SHI Chuang, ZHANG Dong, SONG Wei, et al. BeiDou wide-area precise timing prototype system[J]. Acta Geodaetica et Cartographica Sinica, 2020, 49(3):269-277. DOI:10.11947/j.AGCS.2020.20180534.
[35] HE Chengpeng, GU Shengfeng, LIU Cheng, et al. Simulation research on PPP-RTK performance based on BDS GEO satellite[J]. Measurement Science and Technology, 2022, 33(6):065025. DOI:10.1088/1361-6501/ac55a8.
[36] YANG Xinhao, GU Shengfeng, GONG Xiaopeng, et al. Regional BDS satellite clock estimation with triple-frequency ambiguity resolution based on undifferenced observation[J]. GPS Solutions, 2019, 23(2):33. DOI:10.1007/s10291-019-0828-0.
[37] SHI Chuang, GUO Shiwei, GU Shengfeng, et al. Multi-GNSS satellite clock estimation constrained with oscillator noise model in the existence of data discontinuity[J]. Journal of Geodesy, 2019, 93(4):515-528. DOI:10.1007/s00190-018-1178-3.