Undifferenced and uncombined PPP-RTK:algorithmic models,prototype terminals and field-test results

doi:10.11947/j.AGCS.2022.20210465

Abstract

Abstract: The emerging industries like intelligent driving,precision agriculture and the drones require the global navigation satellite system (GNSS) to provide faster and more accurate positioning services.The undifferenced and uncombined PPP-RTK combines the advantages of precise point positioning (PPP) and those of real-time kinematic (RTK) technique,enabling one to process flexibly the multi-frequency and multi-GNSS data,and achieve rapidly the high-precision positioning with wide-area coverage.However,PPP-RTK is still in the stage of technology research and development;its industrial application has not yet completely formed.From theory to practice,this study formulates the code and frequency division multiple access undifferenced and uncombined PPP-RTK models,develops the corresponding real-time processing software,and designs a set of prototype terminals.Based on the precise corrections estimated by the Beijing-Tianjin-Hebei reference network with the inter-station distance of 154 km,we mount these terminals on a drone,an agricultural tractor and a car to carry out real-time positioning experiments.The results show that the times to first fix for three scenarios are 5 s,2 s and 7 s,the success rates of ambiguity resolution are 99.79%,99.14%,and 98.96%,respectively.The horizontal and vertical positioning accuracy are about 1 cm and 4 cm for all three scenarios.The results demonstrate that our PPP-RTK implementations can provide continuous,reliable and accurate positioning services.

Key words: GNSS, undifferenced and uncombined, real-time, PPP-RTK, prototype terminal

CLC Number:

P228

ZHANG Baocheng, KE Cheng, ZHA Jiuping, HOU Pengyu, LIU Teng, YUAN Yunbin, LI Zishen. Undifferenced and uncombined PPP-RTK:algorithmic models,prototype terminals and field-test results[J]. Acta Geodaetica et Cartographica Sinica, 2022, 51(8): 1725-1735.

References

[1] 杨元喜.北斗卫星导航系统的进展,贡献与挑战[J].测绘学报, 2010, 39(1):1-6. YANG Yuanxi. Progress, contribution and challenges of Compass/BeiDou satellite navigation system[J]. Acta Geodaetica et Cartographica Sinica, 2010, 39(1):1-6.
[2] HEIN G W. Status, perspectives and trends of satellite navigation[J]. Satellite Navigation, 2020, 1(1):1-12.
[3] YANG Y, MAO Y, SUN B. Basic performance and future developments of BeiDou global navigation satellite system[J]. Satellite Navigation, 2020, 1(1):1-8.
[4] YANG Y, GAO W, GUO S, et al. Introduction to BeiDou-3 navigation satellite system[J]. Navigation, 2019, 66(1):7-18.
[5] YANG Y, LIU L, LI J, et al. Featured services and performance of BDS-3[J]. Science Bulletin, 2021, 66(20):2135-2143.
[6] 刘经南,叶世榕. GPS非差相位精密单点定位技术探讨[J].武汉大学学报(信息科学版), 2002, 27(3):234-240. LIU Jingnan, YE Shirong. GPS precise point positioning using undifferenced phase observation[J]. Geomatics and Information Science of Wuhan University, 2002, 27(3):234-240.
[7] KOUBA J, HÉROUX P. Precise point positioning using IGS orbit and clock products[J]. GPS solutions, 2001, 5(2):12-28.
[8] 黄丁发,周乐韬,李成钢. GPS增强参考站网络理论[M].北京:科学出版社, 2011. HUANG Dingfa, ZHOU Letao, LI Chenggang. GPS enhanced reference station network theory[M]. Beijing:Science Press, 2011.
[9] RIZOS C. Network RTK research and implementation-a geodetic perspective[J]. Journal of Global Positioning Systems, 2009, 1(2):144-150.
[10] WABBENA 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, California, U.S.:[s.n.], 2005:2584-2594.
[11] 张小红,胡家欢,任晓东. PPP/PPP-RTK新进展与北斗/GNSS PPP定位性能比较[J].测绘学报, 2020, 49(9):1084. DOI:10.11947/j.AGCS.2020.20200328. ZHANG Xiaohong, HU Jiahuan, REN Xiaodong. New progress of PPP/PPP-RTK and positioning performance comparison of BDS/GNSS PPP[J]. Acta Geodaetica et Cartographica Sinica, 2020, 49(9):1084. DOI:10.11947/j.AGCS.2020.20200328.
[12] GE M, 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.
[13] LAURICHESSE D, MERCIER F, BERTHIAS J P, et al. Integer ambiguity resolution on undifferenced GPS phase measurements and its application to PPP and satellite precise orbit determination[J]. Navigation, 2009, 56(2):135-149.
[14] COLLINS P, BISNATH S, LAHAYE F, et al. Undifferenced GPS ambiguity resolution using the decoupled clock model and ambiguity datum fixing[J]. Navigation, 2010, 57(2):123-135.
[15] TEUNISSEN P J G, ODIJK D, ZHANG B. PPP-RTK:results of CORS network-based PPP with integer ambiguity resolution[J]. Journal of Aeronautics, Astronautics and Aviation, Series A, 2010, 42(4):223-230.
[16] ZHANG B, TEUNISSEN P J G, ODIJK D. A novel un-differenced PPP-RTK concept[J]. Journal of Navigation, 2011, 64(S1):S180-S191.
[17] KHODABANDEH A, TEUNISSEN P J G. PPP-RTK and inter-system biases:the ISB look-up table as a means to support multi-system PPP-RTK[J]. Journal of Geodesy, 2016, 90(9):837-851.
[18] ODIJK D, ZHANG B, KHODABANDEH A, et al. On the estimability of parameters in undifferenced, uncombined GNSS network and PPP-RTK user models by means of S-system theory[J]. Journal of Geodesy, 2016, 90(1):15-44.
[19] 伍冠滨,陈俊平,伍晓勐,等.基于非差非组合PPP-RTK的大气改正模型及其性能验证[J].测绘学报, 2020, 49(11):1407-1418. DOI:10.11947/j.AGCS.2020.20200103. WU Guanbin, CHEN Junping, WU Xiaomeng, et al. Modeling and assessment of regional atmospheric corrections based on undifferenced and uncombined PPP-RTK[J]. Acta Geodaetica et Cartographica Sinica, 2020, 49(11):1407-1418. DOI:10.11947/j.AGCS.2020.20200103.
[20] TU R, ZHANG P, ZHANG R, 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):837-47.
[21] ZHANG B, HOU P, ZHA J, et al. Integer-estimable FDMA model as an enabler of GLONASS PPP-RTK[J]. Journal of Geodesy, 2021, 95(8):1-21.
[22] LAURICHESSE D, PRIVAT A. An open-source PPP client implementation for the CNES PPP-WIZARD demonstrator[C]//Proceedings of the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation. Tampa, Florida:[s.n.], 2015:2780-2789.
[23] BANVILLE S, HASSEN E, LAMOTHE P, et al. Enabling ambiguity resolution in CSRS-PPP[J]. Journal of the Institute of Navigation, 2021, 68(2):433-451.
[24] GENG J, YANG S, GUO J. Assessing IGS GPS/Galileo/BDS-2/BDS-3 phase bias products with PRIDE PPP-AR[J]. Satellite Navigation, 2021, 2(1):1-15.
[25] TEUNISSEN P J G. The ionosphere-weighted GPS baseline precision in canonical form[J]. Journal of Geodesy, 1998, 72(2):107-111.
[26] WANG K, KHODABANDEH A, TEUNISSEN P J G. A study on predicting network corrections in PPP-RTK processing[J]. Advances in Space Research, 2017, 60(7):1463-1477.
[27] TEUNISSEN P J G. A new GLONASS FDMA model[J]. GPS Solutions, 2019, 23(4):1-19.
[28] 查九平.非差非组合PPP-RTK区域网数据处理理论方法及应用研究[D].武汉:中国科学院精密测量科学与技术创新研究院, 2021. ZHA Jiuping. Study on the theoretical methodology and applications of undifferenced and uncombined PPP-RTK based on regional reference network[D]. Wuhan:Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 2021.
[29] TEUNISSEN P J G. A canonical theory for short GPS baselines. part IV:precision versus reliability[J]. Journal of Geodesy, 1997, 71(9):513-525.
[30] KHODABANDEH A, TEUNISSEN P J G. An analytical study of PPP-RTK corrections:precision, correlation and user-impact[J]. Journal of Geodesy, 2015, 89(11):1109-1132.
[31] TEUNISSEN P J G. The least-squares ambiguity decorrelation adjustment:a method for fast GPS integer ambiguity estimation[J]. Journal of Geodesy, 1995, 70(1-2):65-82.
[32] TEUNISSEN P J G. Quality control and GPS[M]//GPS for Geodesy. Berlin, Heidelberg:Springer. 1998:271-318.
[33] VERHAGEN S, LI B, TEUNISSEN P J G. Ps-LAMBDA:ambiguity success rate evaluation software for interferometric applications[J]. Computers&geosciences, 2013, 54:361-376.