Assessment of Different Approaches of Dynamic/Static Datum Transformation in Egypt using Different Plate Motion Models
Tarek W. Hassan1, Mohamed El-Tokhey2, Tamer F. Fath-Allah3, Ahmed E. Ragheb4
1Tarek W. Hassan*, Public Works Department, Ain Shams University/ Faculty of Engineering, Cairo, Egypt.
2Mohamed El-Tokhey, Public Works Department, Ain Shams University/ Faculty of Engineering, Cairo, Egypt.
3Tamer F. Fath-Allah, Public Works Department, Ain Shams University/ Faculty of Engineering, Cairo, Egypt.
4Ahmed E. Ragheb, Public Works Department, Ain Shams University/ Faculty of Engineering, Cairo, Egypt.
Manuscript received on 10 December 2017 | Revised Manuscript received on 18 December 2017 | Manuscript Published on 30 December 2017 | PP: 152-160 | Volume-7 Issue-2, December 2017 | Retrieval Number: B5266127217/17©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: In this work, one critical geodetic issue in Egypt is discussed. The dynamic nature of the International Terrestrial Reference Frame (ITRF) as a geodetic datum, while the Global Positioning System (GPS) network in Egypt is tied to a static datum (ITRF94 epoch 1996) is considered a very critical geodetic issue. Tying any derived ITRF coordinates to the Egyptian network cannot be directly applied due to the effect of the tectonic motion of the African plate, in addition to the datum definition change from one ITRF realization to another. The simplest solution for this problem is neglecting the effect of the datum definition change and using a Plate Motion Model (PMM) for the backward propagation of coordinates until the specified epoch of the static datum. However, the most opportune solution is applying the 14-parameter datum transformation. Assessment the quality of both solutions based on recent Global Navigation Satellite System (GNSS) observations will be presented in this study. In addition, a new set of 14 parameters is derived to describe the transformation process of the African plate in a better way. Four stations of the Egyptian network were used in the assessment by comparing the transformed coordinates to the known coordinates, tied to ITRF94 epoch 1996. Also, 5 different PMM(s) were used to assess the compatibility of the recent PMM(s) with the actual tectonic plate motion in Egypt. This study shows that using the derived parameters in the 14-parameter transformation model gives the best results among all approaches. In addition, using PMM: APKIM2005D or ITRF2008-PMM as the adopted PMM gave the best results, while using NNR-MORVEL56 and PB2002 gave the worst results. For the horizontal component differences, the 14-parameter transformation model with the derived parameters approach could reach to 1.3cm with Root Mean Square (RMS) 3.1cm in case of using APKIM2005D and 1cm with RMS 2.3cm in case of using ITRF2008-PMM. On the other hand, for the vertical component differences, they ranged from 0.8cm to 10.9cm with RMS 8.6cm. Generally, using the derived parameters in the 14-parameter transformation model adopting APKIM2005D or ITRF2008-PMM as the used PMM can be applied to any recently derived coordinates, tied to the latest ITRF realization, to tie them to the Egyptian static datum.
Keywords: Datum Transformation, Dynamic Datums, GNSS, ITRF, Plate Motion Models, Static Datums.
Scope of the Article: Transformation