Evaluation of Precise Point Positioning method with different combinations of Dual-frequencies of Galileo and BeiDou using PPPteh software

Document Type : Research Article


1 Ph.D. Student, Department of Surveying and Geomatics Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran

2 Assistant Professor, Department of Surveying and Geomatics Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran

3 Professor, Department of Surveying and Geomatics Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran


Due to advances in global navigation satellite systems, it has been possible for satellites to send different frequencies. For this reason, different combinations of these frequencies can be considered to form ionospheric codes and phase observations. In this study, the aim is to evaluate the Precise Point Positioning method using a combination of different frequencies. For this purpose, the PPPteh software provided by the authors, written under MatLab is used. PPPteh has the ability to process observations from four GPS, GLONASS, BeiDou and Galileo satellite systems to perform precise point positioning. In this software, there are all possible combinations for making Dual-frequency ionosphere-free observations for all different frequencies. There are three modes for combining different frequencies for the GPS positioning system, ten modes for the Galileo system, and three modes for building the BeiDou satellite system to make ionospheric-free observations. To evaluate the precise point positioning method, four steps have been considered in terms of position accuracy and convergence time: 1) First, use the observations of two frequencies  related to GPS and determine the position, 2) Combine the two systems satellite GPS and Galileo and select the best combination model, 3) Combining the two systems GPS and BeiDou and selecting the best combination and 4) Finally, after the previous three steps, the combination position will be determined using the three systems by the best frequency model and the results will be compared with each other. Based on the results provided for the Galileo and BeiDou navigation satellite systems, two combinations  and were selected as the best combinations for use in determining the precise point positioning, respectively. Following the precise point positioning, the addition of observations on BeiDou satellites has reduced convergence time and, in most cases, increased the three-dimensional accuracy of the coordinate components. Using a combination of the signals has a better quality than the other two combinations. The same process was followed for observations of Galileo satellites, according to which the use of observations related to Galileo satellites when combined with GPS observations has increased accuracy and reduced convergence time. The use of  signal signals is of better combination than the other three combinations. Finally, by combining all three systems and considering the selected frequency model in the first stage, it was concluded that the combination of three satellite navigation satellite systems GPS, Galileo and BeiDou significantly improved both in reducing convergence time and increasing the three-dimensional accuracy of the coordinates provided. Also, the error provided (the difference in the estimated coordinates with the final coordinates of the station from the IGS file), when using the Galileo and BeiDou systems in combination with the GPS, is noticeably different both in convergence and in the accuracy of the coordinates. Combining all three systems together increases accuracy and reduces convergence time. But in dual-combination with GPS, the use of Galileo satellite observations gives us higher accuracy as well as less convergence time. Therefore, choosing the right signals to form ionosphere-free observations in determining the exact absolute position as well as combining different observations with the correct weight for each signal in combination with GPS, can meet the user's needs in terms of accuracy and convergence.


Main Subjects

Abd Rabbou, M. and El-Rabbany, A., 2015, PPP accuracy enhancement using GPS/GLONASS observations in kinematic mode, Positioning, 6(01), p.1.
Alexander, K., 2014. US GPS program and policy update. 26th SBAS International Working Group, pp.24-29.
Bisnath, S. and Gao, Y., 2009, Current state of precise point positioning and future prospects and limitations, In Observing our changing earth (pp. 615-623), Springer, Berlin, Heidelberg.
Cai, C., Gao, Y., Pan, L. and Zhu, J., 2015, Precise point positioning with quad-constellations: GPS, BeiDou, GLONASS and Galileo, Advances in space research, 56(1), 133-143.
Cao, W., Hauschild, A., Steigenberger, P., Langley, R. B., Urquhart, L. and Santos, M., 2010, Performance evaluation of integrated GPS/GIOVE precise point positioning.
El-Rabbany, A., 2002, Introduction to GPS: the global positioning system, Artech house.
Li, X., Ge, M., Dai, X., Ren, X., Fritsche, M., Wickert, J. and Schuh, H., 2015, Accuracy and reliability of multi-GNSS real-time precise positioning: GPS, GLONASS, BeiDou, and Galileo, Journal of Geodesy, 89(6), 607-635.
Nurmi, J., Lohan, E. S., Sand, S. and Hurskainen, H. eds., 2015, GALILEO positioning technology (Vol. 176), Dordrecht, The Netherlands Springer.
Yang, Y., Gao, W., Guo, S., Mao, Y. and Yang, Y., 2019, Introduction to BeiDou‐3 navigation satellite system, Navigation, 66(1), 7-18.
Chengqi, R., 2012, April. Development of the BeiDou navigation satellite system, In Global navigation satellite systems, Report of the Joint Workshop of the National Academy of Engineering and the Chinese Academy of Engineering, Washington, DC.
Farzaneh, S., Safari, A. and Parvazi, K., 2020, Evaluation of statistical models of precise point positioning based on satellites elevation angles, Jornal of earth and space physics, 45(4), 99-119. doi: 10.22059/jesphys.2019. 269327.1007060.
Gao, Y. and Shen, X., 2002, A New Method for Carrier‐Phase‐Based Precise Point Positioning, Navigation, 49(2), 109-116.
Geng, J. and Bock, Y., 2013, Triple-frequency GPS precise point positioning with rapid ambiguity resolution, Journal of geodesy, 87(5), 449-460.
Guo, F., Zhang, X., Wang, J. and Ren, X., 2016, Modeling and assessment of triple-frequency BDS precise point positioning, Journal of geodesy, 90(11), 1223-1235.
Hofmann-Wellenhof, B., Lichtenegger, H. and Wasle, E., 2007, GNSS–global navigation satellite systems: GPS, GLONASS, Galileo, and more, Springer Science & Business Media.
Kouba, J. and Héroux, P., 2001, Precise point positioning using IGS orbit and clock products, GPS solutions, 5(2), 12-28.
Li, P. and Zhang, X., 2014, Integrating GPS and GLONASS to accelerate convergence and initialization times of precise point positioning, GPS solutions, 18(3), 461-471.
Pan, L., Zhang, X. and Guo, F., 2019, Characterizing inter-frequency bias and signal quality for GLONASS satellites with triple-frequency transmissions, Advances in Space Research, 64(7), 1398-1414.
Parvazi, K., Farzaneh, S. and Safari, A., 2020, Role of the RLS-VCE-estimated stochastic model for improvement of accuracy and convergence time in multi-GNSS precise point positioning, Measurement, 165, p.108073.
Tegedor, J., Øvstedal, O. and Vigen, E., 2014, Precise orbit determination and point positioning using GPS, Glonass, Galileo and BeiDou.
White, R. M. and Langley, R. B., 2015, October. Precise Point Positioning with Galileo Observables, In Proceedings of 5th Int, Colloquium on Scientific and Fundamental Aspects of the Galileo Programme (pp. 27-29).
Zangeneh-Nejad, F., Amiri-Simkooei, A. R., Sharifi, M. A. and Asgari, J., 2018, Recursive least squares with additive parameters: Application to precise point positioning, Journal of Surveying Engineering, 144(4), p.04018006.
Zumberge, J. F., Heflin, M. B., Jefferson, D. C., Watkins, M. M. and Webb, F. H., 1997, Precise point positioning for the efficient and robust analysis of GPS data from large networks, Journal of geophysical research: solid earth, 102(B3), 5005-5017.