National Cartographic Center 26 Dec 2021 - 13:24 https://www.ncc.gov.ir/en/news/4889/latest-international-terrestrial-reference-framework-itrf-2020-becomes-operational -------------------------------------------------- General Department of Geodesy and Land Surveying announces: Title : Latest International Terrestrial Reference Framework ITRF 2020 Becomes Operational -------------------------------------------------- Since the establishment of the IERS International Service, which produces earth rotation parameters and reference frameworks, 13 copies of ITRF have been published from ITRF88 to ITRF2014. A network of stations that have their position and speed precisely defined the reference framework, that is a practical realization of the reference system,. Text : According to NCC News, Each reference framework station plays a valuable role in participating in and accessing the ITRF, and the highest quality GNSS stations in the world are considered for this purpose. With Tehran global Station (TEHN) which is one of the top GNSS stations in the world, National Cartographic Center of IRAN (NCC) has showed its role well in determining the ITRF reference framework. This quality directly affects the level of accuracy. Each new version of ITRF contains more data and more accurate computational algorithms than its predecessor. The latest version is ITRF2014, which besides position and velocity, was operated using time series and parameters of the Earth s rotation, and provided accurate quantities of displacements and deformations during earthquakes and post-earthquakes caused by large earthquakes. ITRF2020 is the most recently updated version of the International Terrestrial Reference Framework, released in 2021 and is based on the results of reprocessing of 4 techniques (VLBI, SLR, GNSS and DORIS). The strategy used in the new version has improved combined computing includes modeling the nonlinear motions of the stations, evaluating the observational and computational compatibility of the common observation and local stations. National Cartographic Center of IRAN (NCC), as the custodian of all surveying activities and also in order to prevent parallel work - lack of coordination and incompatibility of coordinates must define the maintenance and updating of the coordinate reference framework in the country based on current world standards. In this regard, all organizations and private companies are required to use this national authority to ensure the coherence and integration in all mapping activities and in a single system. Currently, the country reference framework is based on ITRF2014, which will soon be transferred to ITRF2020