GLONASSZeit

GLONASSZeit is the term used in some German-language sources to describe the time scale underlying the GLONASS satellite navigation system. It denotes the reference clock time used by GLONASS for satellite and receiver timing, and is the basis for clock corrections transmitted by the satellites.

GLONASSTime, or GLO Time, is a continuous, SI-second-based time scale maintained by the GLONASS system and the Russian time service. It is not kept in exact lockstep with UTC, and in practice is described as having a fixed offset relative to UTC that has historically been close to a three-hour difference. Because UTC periodically adds leap seconds, the offset between GLONASSZeit and UTC changes when leap seconds are introduced.

In GLONASS navigation messages, each satellite provides information related to its onboard clock, enabling receivers to estimate the GLO time and, from that, determine precise positioning. The time reference is broadcast along with the satellite’s ephemeris and clock corrections, allowing users to synchronize to GLONASS Zeit for navigation and timing applications.

Within the GNSS community, GLONASSZeit is one component of a multilayer time framework used by multi-constellation receivers. It plays a key role in precise timing, time transfer, and synchronization tasks, especially in systems and applications relying on Russian timing infrastructure. In practice, timing solutions may combine GLONASS Zeit with other time scales (such as GPS time and UTC) to achieve coordinated global timing.

See also: GLONASS, GNSS time scales, GPS time, UTC.