Abstract
The ionosphere significantly impacts Global Navigation Satellite Systems (GNSS) positioning accuracy, particularly in regions with pronounced ionospheric irregularities and high solar activity, such as Egypt. These regions face more challenges in ionospheric modeling compared to the higher-latitude areas. This study provides a detailed assessment of different approaches to Total Electron Content (TEC) estimation in Egypt and their impact on GNSS positioning accuracy using single-frequency receivers. The approaches include the traditional Klobuchar model, Global Ionospheric Maps (GIMs), and the Artificial Neural Network (ANNTEC) model. This ANN model was developed to predict the TEC over Egypt using 10 years of GNSS observations and ionospheric data. The assessment process is performed in two scenarios: static and kinematic positioning. The positioning accuracy employing each approach is evaluated relative to reference coordinates tied to the International Terrestrial Reference Frame 2020 (ITRF-2020) through the nearest International GNSS Service (IGS) stations. The results indicate that the ANNTEC model outperforms the other approaches in both kinematic and static scenarios. In the static mode, the Root Mean Square Error (RMSE) value of the horizontal positions can be improved by 46.6 % and 24.5 % compared to using the Klobuchar model and the GIMs, respectively. In addition, in the kinematic mode, the RMSE value was reduced by 54.7 % and 25.8 % compared to using the Klobuchar model and the GIMs, respectively. These results demonstrate the potential of employing the ANNTEC model to enhance single-frequency GNSS positioning accuracy in Egypt.
-
Research ethics: Not applicable.
-
Informed consent: Not applicable.
-
Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
-
Use of Large Language Models, AI and Machine Learning Tools: None declared.
-
Conflict of interest: The authors state no conflict of interest.
-
Research funding: None declared.
-
Data availability: Data used in this paper is available from the authors upon request.
References
1. Hoffmann-Wellenhof, B, Lichtenegger, H, Wasle, E. GNSS; GPS, GLONASS, Galileo & more. NewYork: SpringerWien; 2008.Suche in Google Scholar
2. Seeber, G. Satellite Geodesy, 2nd ed.. Berlin, New York: Walter de Gruyter; 2003.10.1515/9783110200089Suche in Google Scholar
3. Bolla, P, Borre, K. Performance analysis of dual-frequency receiver using combinations of GPS L1, L5, and L2 civil signals. J Geod 2019;93:437–47. https://doi.org/10.1007/s00190-018-1172-9.Suche in Google Scholar
4. Choy, S, Zhang, K, Silcock, D. An evaluation of various ionospheric error mitigation methods used in single frequency PPP. J Glob Position Syst 2008;7:62–71. https://doi.org/10.5081/jgps.7.1.62.Suche in Google Scholar
5. Teunissen, PJG, Montenbruck, O. Springer handbook of global navigation satellite systems. Cham, Switzerland: Springer International Publishing; 2017.10.1007/978-3-319-42928-1Suche in Google Scholar
6. Klobuchar, JA. Ionospheric time-delay algorithm for single-frequency GPS users. IEEE Trans Aerosp Electron Syst 1987;AES-23:325–31. https://doi.org/10.1109/taes.1987.310829.Suche in Google Scholar
7. Coïsson, P, Radicella, SM, Leitinger, R, Nava, B. Topside electron density in IRI and NeQuick: features and limitations. Adv Space Res 2006;37:937–42. https://doi.org/10.1016/j.asr.2005.09.015.Suche in Google Scholar
8. Wu, X, Zhou, J, Tang, B, Cao, Y, Fan, J. Evaluation of COMPASS ionospheric grid. GPS Solut 2014;18:639–49. https://doi.org/10.1007/s10291-014-0394-4.Suche in Google Scholar
9. Xue, K, Liu, R, Wang, J, Bai, J. Research on Klobuchar improved model based on the measured data of BeiDou satellite navigation system in Tianjin area. In: Proceedings of the 2018 international technical meeting of the institute of navigation; 2018:751–62 pp.10.33012/2018.15591Suche in Google Scholar
10. Eastes, RW, Solomon, SC, Daniell, RE, Anderson, DN, Burns, AG, England, SL, et al.. Global-scale observations of the equatorial ionization anomaly. Geophys Res Lett 2019;46:9318–26. https://doi.org/10.1029/2019gl084199.Suche in Google Scholar
11. Setti, PT, da Silva, CM, Alves, DBM. Assessing GNSS ionospheric models at low latitudes: BDGIM, NeQuick-G, and Klobuchar. GPS Solut 2025;29:15. https://doi.org/10.1007/s10291-024-01761-0.Suche in Google Scholar
12. Wang, Z, Zou, S. COMPASS: a new conductance model based on PFISR and SWARM satellite observations. Space Weather 2022;20:e2021SW002958. https://doi.org/10.1029/2021sw002958.Suche in Google Scholar
13. Schaer, S, Gurtner, W, Feltens, J. IONEX: the IONosphere Map EXchange format version 1. Darmstadt, Germany; 1998.Suche in Google Scholar
14. Prakanrattana, K, Satirapod, C. Comparative study of using different ionosphere models in Thailand for single-frequency GNSS users. Surv Rev 2019;51:213–8. https://doi.org/10.1080/00396265.2018.1426260.Suche in Google Scholar
15. Chen, J, Ren, X, Xu, G, Yang, P, Liu, H, Zhang, X. Method and validation of real-time global ionosphere modeling constraint by multi-source GNSS/LEO data. Space Weather 2024;22:e2023SW003800. https://doi.org/10.1029/2023sw003800.Suche in Google Scholar
16. Li, W, Wang, K, Yuan, K. Performance and consistency of final global ionospheric maps from different IGS analysis centers. Remote Sens (Basel) 2023;15:1010. https://doi.org/10.3390/rs15041010.Suche in Google Scholar
17. Verkhoglyadova, O, Meng, X, Kosberg, J. Understanding large-scale structure in global ionospheric maps with visual and statistical analyses. Front Astronom Space Sci 2022;9:852222. https://doi.org/10.3389/fspas.2022.852222.Suche in Google Scholar
18. Bi, H, Huang, L, Zhang, H, Xie, S, Zhou, L, Liu, L. A deep learning-based model for tropospheric wet delay prediction based on multi-layer 1D convolution neural network. Adv Space Res 2024;73:5031–42. https://doi.org/10.1016/j.asr.2024.02.039.Suche in Google Scholar
19. Suzuki, T, Amano, Y. NLOS multipath classification of GNSS signal correlation output using machine learning. Sensors 2021;21:2503. https://doi.org/10.3390/s21072503.Suche in Google Scholar PubMed PubMed Central
20. Li, H, Borhani-Darian, P, Wu, P, Closas, P. Deep neural network correlators for GNSS multipath mitigation. IEEE Trans Aerosp Electron Syst 2022;59:1249–59. https://doi.org/10.1109/taes.2022.3197098.Suche in Google Scholar
21. Hassan, T, El-Tokhey, M. Employing machine learning techniques for estimating the differential code biases of GPS satellites. J Spat Sci 2025;70:121–40. https://doi.org/10.1080/14498596.2024.2371831.Suche in Google Scholar
22. Liu, Z, Lo, S, Walter, T. GNSS interference detection using machine learning algorithms on ADS-B data. In: Proceedings of the 34th international technical meeting of the satellite division of the institute of navigation (ION GNSS+ 2021); 2021:4305–15 pp.10.33012/2021.18111Suche in Google Scholar
23. Tohidi, S, Mosavi, MR. Effective detection of GNSS spoofing attack using a multi-layer perceptron neural network classifier trained by PSO. In: 2020 25th international computer conference, computer society of iran (CSICC); 2020:1–5 pp.10.1109/CSICC49403.2020.9050078Suche in Google Scholar
24. Zhou, C, Yang, L, Su, X, Li, B. Neural network-based ionospheric modeling and predicting—To enhance high accuracy GNSS positioning and navigation. Adv Space Res 2022;70:2878–93. https://doi.org/10.1016/j.asr.2022.07.050.Suche in Google Scholar
25. Takahashi, H, Costa, S, Otsuka, Y, Shiokawa, K, Monico, JFG, Paula, E, et al.. Diagnostics of equatorial and low latitude ionosphere by TEC mapping over Brazil. Adv Space Res 2014;54:385–94. https://doi.org/10.1016/j.asr.2014.01.032.Suche in Google Scholar
26. Charoenkalunyuta, T, Satirapod, C. Effect of Thai Ionospheric Maps (THIM) model on the performance of network based RTK GPS in Thailand. Surv Rev 2014;46:1–6. https://doi.org/10.1179/1752270613y.0000000055.Suche in Google Scholar
27. Xiong, B, Wan, W, Yu, Y, Hu, L. Investigation of ionospheric TEC over China based on GNSS data. Adv Space Res 2016;58:867–77. https://doi.org/10.1016/j.asr.2016.05.033.Suche in Google Scholar
28. Mallika, IL, Ratnam, DV, Raman, S, Sivavaraprasad, G. Performance analysis of neural networks with IRI-2016 and IRI-2012 models over Indian low-latitude GPS stations. Astrophys Space Sci 2020;365:124. https://doi.org/10.1007/s10509-020-03821-6.Suche in Google Scholar
29. Sahu, S, Trivedi, R, Choudhary, RK, Jain, A, Jain, S. Prediction of Total Electron Content (TEC) using neural network over anomaly crest region Bhopal. Adv Space Res 2021;68:2919–29. https://doi.org/10.1016/j.asr.2021.05.027.Suche in Google Scholar
30. Özkan, A. An artificial neural network model in predicting VTEC over central Anatolia in Turkey. Geod Geodyn 2023;14:130–42. https://doi.org/10.1016/j.geog.2022.07.004.Suche in Google Scholar
31. Abdelmaaboud, A, Fathallah, T, Ragheb, A, Gomaa, A, Hassan, T. Artificial neural network-based modeling and prediction of GNSS ionospheric errors in Egypt. J Survey Eng 2025;151:04025008. https://doi.org/10.1061/jsued2.sueng-1571.Suche in Google Scholar
32. Musa, T. Residual analysis of atmospheric delay in low latitude region using network-based GPS positioning. 2007.Suche in Google Scholar
33. Bishop, CM. Pattern recognition and machine learning. New York, NY 10013, USA: Springer; 2006.Suche in Google Scholar
34. Hassan, T, Fath-Allah, T, Elhabiby, M, Awad, AE, El-Tokhey, M. Integration of GNSS observations with volunteered geographic information for improved navigation performance. J Appl Geodesy 2022;16:265–77. https://doi.org/10.1515/jag-2021-0063.Suche in Google Scholar
35. El-Tokhey, M, Mogahed, YM, Mamdouh, M, Hassan, TW. Establishment of new continuous operating reference station (CORS) at faculty of engineering, Ain shams university. Int J Eng Adv Technol (IJEAT), ISSN 2018:2249–8958.Suche in Google Scholar
© 2025 Walter de Gruyter GmbH, Berlin/Boston