3D Modelling of Earth Kinematics in Palestine for GNSS and Geodetic Time-Dependent Positioning

Abstract

Abstract: The use of GNSS technologies for precise point positioning enabled the calculations for single-point observations or relative positioning of long baselines. The GNSS absolute and relative positioning techniques can be implemented between points within different tectonic plates, while the classical surveying methods start from local reference/triangulation points to near points within a few kilometers. The definition of the kinematic models of the earth has become an important role in GNSS measurements techniques and networks adjustment methods based on international terrestrial reference frames (ITRF), where the reference points can be located in different continents and tectonic plates. Thus, the position calculations in the ITRF systems are time-dependent. To satisfy the requirements of land and cadastral surveying, the bidirectional transformation between classical geodetic networks and GNSS global, regional and local networks is nowadays a primary requirement in modern geodesy. While the classical networks were defined locally assuming a static earth system, the ITRF coordinates by GNSS techniques are defined globally and directly affected by earth kinematics including plate tectonics and local crustal movements. However, Palestine has a special kinematic situation because it is located at the border between two plates; Nubia/Sinai plate and the Arabia plate along the Jordan valley line. Thus, the result is unsteady surface kinematics all over the country, which has a longitudinal shape parallel to the Jordan valley rift. Using the IGS/EUREF stations and GNSS stations data that are freely available on the internet, varying positional velocities were calculated in both magnitude and direction using years of daily available GNSS raw observations. The GNSS precise observation techniques have proven that the points of the classical networks were subjected to a kinematic situation over the years. Therefore, the Palestinian geodetic network has to be revised for kinematic effects for the integration with the modern GNSS positioning. In this work, the effect of surface movements is included in the calculations between the different ITRF coordinate systems and the classical geodetic network of Palestine. To achieve the required transformations between ITRF and the classical network, a velocities model was established and tested utilizing GIS raster interpolation. The accuracy of the modeled velocities could support 1cm in static or real-time GNSS positioning. This made it possible for the integration between geodetic measurements between different time epochs.