Abstract

SIRGAS responds to the acronym of Geocentric Reference System for the Americas (SIstema de Referencia Geocéntrico para las AméricaS) and is a non-profit organization based on the contribution at the American level of organizations, universities, institutes, etc., with a close relationship with geodetic and geophysical activities. Its objective is to facilitate the member countries' access to a unified reference system as for the geometric component (densifying the ITRF) as for the physical component (densifying the IHRF). The geometric aspects are coordinated by the SIRGAS Working Group I (Reference system) at the continental level and by the SIRGAS Working Group II (SIRGAS at national level) at the national level. The physical height standardization is coordinated by the SIRGAS Working Group III (Vertical Datum). This contribution exposes the activities related to the Working Group I, whose main objectives are to maintain and to ensure the long-term stability of the SIRGAS reference frame. Presently, SIRGAS is realized by a network of about 440 continuously operating GNSS stations, which are processed on a weekly basis following the IERS conventions and the GNSS-specific guidelines released by the IGS. The main SIRGAS products are weekly station positions, multi-year solutions, surface deformation models, and tropospheric parameters in hourly intervals. This contribution summarizes recent achievements and open challenges in the maintenance and further development of the SIRGAS Reference Frame. Special care is given to the reprocessing of the SIRGAS reference network based on the ITRF2014 (IGS14 / IGb14) and the extension of the SIRGAS network to North America as a fundamental support for the activities of the GRFA (Geodetic Reference Frame for Americas) working group, established in the framework of the Regional Committee of the United Nations on Global Geospatial Information Management for the Americas (UN-GGIM: Americas).