IHRF Coordination Center, a newly established IAG/IGFS component to ensure the sustainability of the IHRS/IHRF

The International Association of Geodesy (IAG) introduced the International Height Reference System (IHRS) in 2015 as the international standard for the accurate determination of physical heights worldwide. The primary vertical coordinates are geopotential numbers referenced to a conventional W_o value. The realization of the IHRS is the International Height Reference Frame (IHRF), which corresponds to a global network of reference stations with precise reference coordinates, geopotential numbers specified in the IHRS and (X, Y, Z) coordinates in the International Terrestrial Reference Frame (ITRF). In the framework of the IAG and after a strong international collaboration the scientific foundations of the IHRS have been outlined and a first realization of the IHRF has been computed. In that frame, it has been deemed necessary to ensure the long-term sustainability of the IHRF by establishing a new dedicated component within the IAG gravity field related services. Recently (December 2023), the IAG has accepted the establishment of the IHRF Computation Center (IHRF-CC) as a central coordinating body under the responsibility of the International Gravity Field Service (IGFS) with direct adherence to the IGFS Central Bureau (IGFS CB), composed of individual modules taking care of the main components of the IHRF. These modules are the IHRF Reference Network Coordination, the IHRF Conventions’ Coordination, the IHRF Associate Analysis Centers, and the IHRF Combination Coordination. In this work we outline the main components of the IHRF-CC, the objectives and goals foreseen, the main responsibilities of its component as well as their planned interrelation, complementarity and synergies in order to deliver its main products. The latter refer to the IHRS standards and conventions and their update; the update of the IHRF network and status; the IHRF computation cookbook; computation of offsets to national and regional vertical datums; and finally, IHRF station coordinates for the global core network and contributions to regional and national densifications. Finaly, we outline the first steps taken to formulate the IHRF-CC components and initiatives to begin normal operation.