The key role of GNSS for monitoring geodetic parameters of the Earth
Global navigation satellite systems (GNSS) are a fundamental tool for monitoring geodesic parameters of the Earth, building and constantly monitoring the Earth’s reference system and connecting measurements of various satellite geodetic technologies. GNSS consist of a ground segment (GNSS receivers) and an orbital grouping (navigation satellites of the system). The microwave range of GNSS signals allows using these systems in all weather conditions, and the two-frequency carriers allow, to a large extent, eliminating the ionospheric delay of signal propagation. In addition to performing basic geodetic definitions, GNSS can also be used to solve social and other positional measurements that require high accuracy. In this article the author discusses the main tasks solved by GNSS, defines the requirements for the accuracy of navigation systems products, and provides directions for the development of the ground and orbital parts of GNSS taking into account the needs of the international geodetic community.