The Improvement in the Positioning on the Nubian and Somalia Plates by Updating Terrestrial Reference Frames

Abstract

International Terrestrial Reference Frames (ITRF) is an accurate and standard frame for referencing positions at different times and in different locations around the world. The International Global Navigation Satellite System (GNSS) Service, (IGS) enable global positioning and timing at the highest possible accuracy through modernized datum’s aligned with the ITRF. In addition, ITRF site velocities for any location within Africa are between 24 and 31 mm/yr due to rigid motion of the African plate over the underlying mantle. The African plate can be divided into two Nubian and Somalia sub-plates. In the present work, the rotation rates about Euler poles and position improvement in Nubian and Somalia plates with updated ITRFs are investigated. Among the results in this study, when using a rigid plate movement and instantaneous ITRF coordinates to transform a fixed reference epoch, in case of Nubian plate, the residual in positioning and Root Mean Square Error (RMS) improved with the updating of the frame and the best results of residual and RMS appear in frame 2008 by values (0.149,0.011) m. respectively but in Somali plate, residual and RMS increased with the updating of the frame and the best results appear in frame2014 by values (i.,e., 0.096, 0.012) m, respectively.