Assessment of latest global gravity field models by GNSS/Levelling Geoid

Abstract

This paper focuses on making a comparing of GNSS/Levelling data and data obtained from global geopotential models. For comparison, geoid undulations obtained by GNSS/Levelling method and geoid undulations obtained from global geopotential models have been used. As global geopotential models, SGG-UGM-2, XGM2019e_2159, GO_CONS_GCF_2_TIM_R6e, ITSG-Grace2018s, EIGEN-GRGS.RL04.MEAN-FIELD, GOCO06s, GO_CONS_GCF_2_TIM_R6, GO_CONS_GCF_2_DIR_R6 GGMs are used. The data sets used in the improvements of the models are altimetry, satellite, location data and topography. The disparities between the geoid undulations obtained from the GNSS/Levelling method and geoid undulations obtained from global geoid models have been taken. Some statistical criteria for these differences have been calculated. These criteria, such as smallest, biggest, average, standard deviation, Root Mean Square RMS statistical values of deviations between GNSS/Levelling geoid and global geopotential models, are taken into consideration when comparing the models. According to the comparison, the global gravity field model that best fits the GNSS/Levelling is selected.

Keywords

• GGMs
• GNSS/Levelling
• Geoid
• Statistical values

References

1. Apeh, O. I., Moka, E. C., & Uzodinma, V. N. (2018). Evaluation of gravity data derived from global gravity field models using terrestrial gravity data in Enugu State, Nigeria. Journal of Geodetic Science, 8(1), 145-153.
2. Heiskanen, W. A. (1967). Physical geodesy. Determination of the Geoid from Ground Anomalies, 8, 325-330.
3. Yilmaz, M., Turgut, B., Gullu, M., & Yilmaz, I. (2016). Evaluation of recent global geopotential models by GNSS/Levelling data: internal Aegean region. International Journal of Engineering and Geosciences, 1(1), 15-19.
4. El-Ashquer, M., Al-Ajami, H., Zaki, A., & Rabah, M. (2020). Study on the selection of optimal global geopotential models for geoid determination in Kuwait. Survey review, 52(373), 373-382. https://doi.org/10.1080/00396265.2019.1611256.
5. Pavlis, N. K., Holmes, S. A., Kenyon, S. C., & Factor, J. K. (2012). The development and evaluation of the Earth Gravitational Model 2008 (EGM2008). Journal of geophysical research: solid earth, 117(B4). https://doi.org/10.1029/2011jb008916.
6. Liang, W., Li, J., Xu, X., Zhang, S., & Zhao, Y. (2020). A high-resolution Earth’s gravity field model SGG-UGM-2 from GOCE, GRACE, satellite altimetry, and EGM2008. Engineering, 6(8), 860-878.
7. Pail, R., Bruinsma, S., Migliaccio, F., Förste, C., Goiginger, H., Schuh, W. D., ... & Tscherning, C. C. (2011). First GOCE gravity field models derived by three different approaches. Journal of Geodesy, 85(11), 819-843. https://doi.org/ 10.1007/s00190-011-0467-x.
8. Save, H., Bettadpur, S., & Tapley, B. D. (2016). High‐resolution CSR GRACE RL05 mascons. Journal of Geophysical Research: Solid Earth, 121(10), 7547-7569. https://doi.org/10.1002/2016JB013007.

9. Watkins, M. M., Wiese, D. N., Yuan, D. N., Boening, C., & Landerer, F. W. (2015). Improved methods for observing Earth's time variable mass distribution with GRACE using spherical cap mascons. Journal of Geophysical Research: Solid Earth, 120(4), 2648-2671. https://doi.org/10.1002/2014JB011547.
10. Ince, E. S., Abrykosov, O., Förste, C., & Flechtner, F. (2020). Forward gravity modelling to augment high-resolution combined gravity field models. Surveys in Geophysics, 41(4), 767-804. https://doi.org/10.1007/s10712-020-09590-9.
11. Ogutcu, S. (2020). Performance assessment of IGS combined/JPL individual rapid and ultra-rapid products: Consideration of Precise Point Positioning technique. International Journal of Engineering and Geosciences, 5(1), 1-14.
12. Tusat, E., & Ozyuksel, F. (2018). Comparison of GPS satellite coordinates computed from broadcast and IGS final ephemerides. International Journal of Engineering and Geosciences, 3(1), 12-19.
13. Pırtı, A., Hoşbaş, R. G., Şenel, B., Köroğlu, M., & Bilim, S. (2021). Galileo uydu sistemi ve sinyal yapısı. Geomatik, 6(3), 207-216.
14. Başçiftçi, F. (2021). TUSAGA-AKTİF Noktalarında Gürültü Analizi, Türkiye’nin Güneydoğusu Örneği. Geomatik, 6(2), 135-147.
15. Özdemir, E. G. (2022). Bağıl ve mutlak (PPP) konum çözüm yaklaşımı sunan Web-Tabanlı çevrimiçi veri değerlendirme servislerinin farklı gözlem periyotlarındaki performanslarının araştırılması. Geomatik, 7(1), 41-51.
16. Zingerle, P., Pail, R., Gruber, T., & Oikonomidou, X. (2020). The combined global gravity field model XGM2019e. Journal of Geodesy, 94(7), 1-12. https://doi.org/10.1007/s00190-020-01398-0.
17. Zingerle, P., Brockmann, J. M., Pail, R., Gruber, T., & Willberg, M. (2019). The polar extended gravity field model TIM_R6e. https://doi.org/10.5880/ICGEM.2019.005.
18. Kvas, A., Behzadpour, S., Ellmer, M., Klinger, B., Strasser, S., Zehentner, N., & Mayer‐Gürr, T. (2019). ITSG‐Grace2018: Overview and evaluation of a new GRACE‐only gravity field time series. Journal of Geophysical Research: Solid Earth, 124(8), 9332-9344. https://doi.org/10.1029/2019JB017415.
19. Lemoine, J. M., Bourgogne, S., Biancale, R., Reinquin F., & Bruinsma, S. (2019). EIGEN-GRGS.RL04.MEAN-FIELD – Mean Earth gravity field model with a time-variable part from CNES/GRGS RL04. 25 Years of Progress in Radar Altimetry Symposium, 24-29 September, Portugal.
20. Kvas, A., Brockmann, J. M., Krauss, S., Schubert, T., Gruber, T., Meyer, U., ... & Pail, R. (2021). GOCO06s–a satellite-only global gravity field model. Earth System Science Data, 13(1), 99-118. https://doi.org/10.5194/essd-13-99-2021.
21. Brockmann, J. M., Schubert, T., & Schuh, W. D. (2021). An improved model of the Earth’s static gravity field solely derived from reprocessed GOCE data. Surveys in Geophysics, 42(2), 277-316. https://doi.org/10.1007/s10712-020-09626-0.
22. Alemu, E. (2021). Evaluation of GGMs based on the terrestrial gravity disturbance and Moho depth in Afar, Ethiopia. Artificial Satellites: Journal of Planetary Geodesy, 56. https://doi.org/10.2478/arsa-2021-0007.